Building

BUILDING

THE art of building comprises the practice of civil architecture, or the mechanical operations necessary to carry the designs of the architect into effect. It is not unfrequently called practical architecture; but the adoption of this term would tend only to confuse, by rendering it difficult to make the distinction generally understood between architecture as a fine or liberal art and architecture as a mechanical art. The execution of works of architecture necessarily includes building, but building is frequently employed when the result is not architectural; a man may be a competent builder without being an architect, but no one can be an accomplished architect unless he be competent to specify and direct all the operations of building. A scientific knowledge of the principles of masonry, carpentry, joinery, &c., and of the qualities, strength, and resistance of materials, though of the utmost importance to an architect, must be attended by a minute acquaintance with a great variety of less ambitious details. Such are those which relate to the arrangement of a plan for the greatest possible degree of convenience on the smallest space, and at the least expense; its transference to the ground; the preparation and formation of foundations; the arrangement and construction of drains, sewers, and vent-shafts; the varieties of walling with stone, and of laying bricks in brickwork; the merit of the various modes of bonding and tying walls, both lengthwise and across; the arrangement of gutters on roofs, to get sufficient fall, and to conduct the water to the least inconvenient places for fixing trunks to lead it down; the arrangement and formation of flues; the protection of walls from damp, of timber from moisture and stagnant air, and of metals generally from exciting causes; the cost of materials and labour, and the quantity of each required to produce certain results. Together with these, an architect ought to be practically acquainted with all the modes of operation in all the trades or arts employed in building, and to be able minutely io estimate beforehand the absolute cost involved in the execution of a proposed structure. The power to do the latter necessarily involves that of measuring work, and ascertaining the quantities done. These things may certainly be referred to the surveyor or measurer, but they are not the less incumbent on the architect, who cannot be said to be thoroughly master of building, or the practice of his profession, unless he be skilled in these operations.

Building includes what is called construction, which is the branch of the science of architecture relating to the practical execution of the works required to produce any structure; it will therefore be necessary to explain the subject in a general manner before entering upon building in detail.

It may, perhaps, be useful to premise that, should it occur to some readers that the present article has too great a tendency to supply information on the manner of building in a modern style, and that the earlier method is not elaborated, it must be remembered that, although the styles of architecture have varied at different periods, buildings, wherever similar materials are employed, must be constructed on much the same principles. Greater scientific knowledge of the natures and properties of materials has, however, given to the modern workman immense advantages over his mediaeval brother craftsman, and caused many changes in the details of the trade, or art of building, although stones, bricks, mortar, &c., then as now, formed the element of the more solid parts of all edifices. The introduction of fir, too, in place of the more sohd and durable timber oak, has likewise occasioned similar changes, too numerous to mention in detail, in the sister arts of carpentry and joinery, probably also causing the division of the carpenter’s trade of the mediaeval period. Certain exceptional features of mediaeval work did exist, and most, if not all, will, it is hoped, be found referred to in this article.

General Principles of Construction.

The object of construction is to adapt and combine fit materials in such a manner that they shall retain in use the forms and dispositions assigned to them. If an upright wall be properly constructed upon a sufficient foundation, the combined mass will retain its position, and bear pressure acting in the direction of gravity, to any extent that the ground on which it stands and the component materials of the wall can sustain. But pressure acting laterally has a necessary tendency to overturn a wall, and therefore it will be the aim of the constructor to compel, as far as possible, all forces that can act upon an upright wall to act in the direction of gravity, or else to give it permanent means of resistance in the direction opposite to that in which a disturbing force may act. Thus when an arch is built to bear against an upright wall, a buttress or other counterfort is applied in a direction opposed to the pressure of the arch. In like manner the inclined roof of a building, spanning from wall to wall, tends to thrust out the walls; and hence a tie is applied to hold the opposite sides of the roof together at its base, where alone a tie can be fully efficient, and thus the roof is made to act upon the walls wholly in the direction of gravity; or where an efficient tie is inapplicable, buttresses or counterforts are added to the walls, to enable them to resist the pressure outwards. A beam laid horizontally from wall to wall, as a girder to carry a floor and its load, may sag or bend downwards, and tend thereby to force out the walls; or the beam itself may break. Both these contingencies are obviated by trussing, which renders the beam stiff enough to place its load on the walls in the direction of gravity, and strong enough to carry it safely. Or if the beam be rigid in its nature, or uncertain in its structure, or both (as cast-iron is), and will break without bending, the constructor, by the smith’s art, will supply a check and ensure it against the possible contingency.

Perfect stability, however, is not to be attained with materials which are subject to influences beyond the control of man, and all matter is subject to certain influences of that nature. The influences mostly to be contended against are heat and humidity, the former of which produces movement of some kind or to some extent in all bodies; the latter, movement in many kinds of matter; whilst the two acting together contribute to the disintegration or decay of materials available for the purposes of construction. These pervading influences the constructor seeks to counteract, by the selection and disposition of his materials accordingly. From the tenacity of wrought iron, and its almost plastic character in the hands of the smith, it is employed to tie together other more bulky but less costly and more rigid materials; but on account of its exceeding susceptibility of heat, and its consequent expansion and contraction, wrought iron must be used in short lengths only, unless where protected from great alternations of heat and cold. The rapid decay, too, of wrought iron when exposed to humidity, and especially when it is alternately wet and dry, will teach the constructor not to expect enduring stability in his works if he makes them dependent upon wrought iron. Cast-iron is brittle, and may not be exposed with impunity to transverse strain, especially if such strain be attended by action tending to induce vibration; it expands and contracts under the influence of heat, but it resists compression in every direction, and if used in small bodies, is valuable as a means of connecting other materials. Timber, being practically unchangeable in the direction of its length from the mere absorption of either heat or humidity, and at the same time practically both inextensible and incompressible in that direction, and being also readily wrought and easily combined alike with other timber and with iron, is a valuable material in the hands of the constructor; but it shrinks and swells in the direction of its thickness, and, in consequence, is subject to rapid decay when exposed to alternations of moisture and dryness; and although in many varieties timber is perdurable and unchangeable in form if it be kept either altogether free from moisture or always wholly wet, its quality of inextensibility is greatly diminished in value to the constructor on account of the comparatively slight resistance it offers to compressing power, and the comparative ease with which its fibrous structure is torn asunder. From this cause it cannot be grasped or otherwise held so that its power of resisting extension may be made available in any degree proportioned to its strength; whilst its quality of incompressibility in the opposite direction is of less value to the constructor for many purposes which require that quality in the material, because it absorbs moisture by the ends of the fibre more readily, and with a far more mischievous effect, than it does in the direction in which it is compressible. Hence timber rots more rapidly by the ends than by the sides.

Stone and brick, the other main available materials in general construction, keep their places in combination by means of gravity. They may be merely packed together, but in general they are compacted by means of mortar or cement, so that although the main constituent materials are wholly incompressible, masses of either or of both combined in structures are compressible until the setting medium has indurated to a like condition of hardness. That kind of stone is best fitted for the purposes of general construction which is least absorbent of moisture, and at the same time free to work. Absorbent stone exposed to the weather rapidly disintegrates; and for the most part non-absorbent stone is so hard that it cannot always be used with a due regard to economy. When, therefore, fitting stone of both qualities can be obtained, the harder stone can be exposed to the weather, or to the action which the softer stone cannot resist, and forms the main body of the structure of the latter so protected. The hard and the soft should be made to bear alike, and should therefore be coursed and bonded together by the mason’s art, whether the work be of stone wrought into blocks and gauged to thickness, or of rough dressed or otherwise unshaped rubble compacted with mortar.

Good bricks are less absorbent of moisture than any stone of the same degree of hardness, and are better nonconductors of heat than stone. As the basis of a stable structure, brickwork is more to be relied upon than stone in the form of rubble, when the constituents bear the relation to one another last above referred to, the setting material being the same in both; because the brick, by its shaped form, seats itself truly, and produces by bonding a more perfectly combined mass; whilst the imperfectly shaped and variously sized stone as dressed rubble can neither bed nor bond truly,·—the inequalities of the form having to be compensated for with mortar, and the irregularity of size of the main constituent accounted for by the introduction of larger and smaller stones. The mo3t perfect stability is to be obtained, nevertheless, from truly wrought and accurately seated and bonded blocks of stone, mortar being used to no greater extent than may be necessary to exclude wind or water, to prevent the disintegrating action of both upon even the most durable stone. When water alone is to be dealt with, and especially when it is liable to act with force, mortar is necessary for securing to every block in the structure its own full weight and the aid of every other collateral and super-imposed stone in order to resist the loosening effect which water in powerful action is sure to produce.

In the application of construction to any particular object, the nature of the object will greatly affect the character of the constructions and the materials of which they are to be formed.

Every piece of construction should be complete in itself, and independent as such of everything beyond it. A door or a gate serves its purpose by an application wholly foreign to itself; but it is a good and effective or a bad and ineffective piece of construction, independently of the posts to which it may be hung. Whilst the wheel of a wheelbarrow, comprising fellies, spokes, and axle-tree, is a piece of construction complete in itself, and independent as such of everything beyond it, an arch of masonry, however large it may be, is not necessarily a piece of construction complete in itself,—it would fall to pieces without abutments. Thus, a bridge consisting of a series of arches, however extensive, may be but one piece of construction, no arch being complete in itself without the collateral arches in the series to serve as its abutments, and the whole series being dependent thereby upon the ultimate abutments of the bridge, without which the structure would not stand. This illustration is not intended to apply to the widely distended masses of the older bridges, by which each pier becomes sufficient to abut the arches springing from it, but which tend, in providing for a way over a river, to choke up the way by the river itself, or compel the river to throw it down, or otherwise destroy its own banks. A bridge, of which the way is formed upon arches of masonry, may be thus but one piece of construction; and in like manner, that paragon of constructive skill, the complete church, whether cathedral or otherwise, as built in the Pointed style when that style was practised in full accordance with true constructive principles, is but one piece of construction. As in the long series of arches in a bridge, viaduct, or other such work, in which the piers are vertical supports to the bridging structure, and may be of no greater substance than is necessary to bear the weight coming directly by vertical pressure from the superincumbent structure and its possible load, but throwing all the pressure arising from weight acting laterally, or as thrust, upon terminal abutments,—nothing may be omitted, as nothing can be removed from the structure of the Pointed arch cathedral, or other church built in that style, the whole system of which is bridge-like in construction, without leaving something unsupported or unresisted that requires vertical support or lateral resistance. The western towers of a Pointed cathedral form effective abutments to the long series of arches of the inner ranges over the piers which stand between the nave and the aisles on both sides, whilst turrets or massive buttresses and deep porches upon the northern and southern transept fronts perform the same services in respect of the arches of the transepts. The counteracting east end of the chancel forms a true constructive abutment to the arches of the chancel, whilst the tower, with, it may be, a spire upon it, at the intersection of the four grand compartments of the cross, gives, by its weight, abuttal to them all. The want of this last-named grand and essential body in the system is but too strongly marked in many of the English cathedrals, by the iron bars which have been applied to tie in the arches of the nave, transepts, and clιanccl, and to relieve the piers upon which the transept arches bear at a higher level from the thrust to which, being without the weight of a tower upon them, they have continually yielded. Transversely the weight and the thrust of the vaulted ceilings of the nave are brought up to, and thrown against, the piers of the clerestory, which stand upon the main piers or columns of the interior below, and are abutted by flying buttresses, which carry the thrust down to the pinnacle-weighted buttresses of the outer aisle walls, which have already received the weight and thrust of the vaulted ceilings of the aisles themselves. Corbels in the walls and spreading capitals upon shafts take the weight directly, and leave the walls and piers but little encumbered in the middle, so that the vertical structure is continued upwards without bearing upon the springing stones of the arches.

But it is not necessary that the arch employed should be the Pointed arch, to produce combinations as effective in construction as the most perfectly designed and extensively elaborated work of the kind referred to as models of constructive skill; the skill consists in a full and clear perception of the bearing and leaning of every part, and of the means necessary to support and counteract the bearings and the leanings within the reasonable limits of the work with reference to its object and purpose—to the end that the work may become complete in itself, and independent as a piece of construction of everything beyond it.

In making reference to the noble works of construction above referred to, in which the art of the mason is iuaιnιy employed, as works exhibiting construction most fully and most truly, the hall must not be passed over without remark, and of all the great halls of the class to which Westminster Hall belongs, it is itself the most effective as a work of construction; and its effect is wholly produced by the magnificent roof which covers it. This roof is a piece of carpentry admirably designed to resolve it into a compact body to act upon the walls in the direction of gravity alone. But the designer may not have felt quite certain of the results, so whilst erecting massive walls on which to place his elaborate combination of timber, he threw up against the lateral walls a series of flying buttresses to check any tendency of the roof to spread under its own weight in the absence of a thorough transverse tie; for these buttresses are said to be independent of the walls, not being built into them.

An application of the principles of construction exhibited in the most perfect works of constructive skill ever executed, as above indicated, may be made in the rougher operations of mere practical utility. The sides of cuttings through certain earths in the formation of lines of inland communication, whether carriage roads, railways, or canals, are sometimes required to be widened out to an inordinate extent because of the looseness or slipperiness of the soil, or must otherwise be retained or held upright by special constructions. The expense of the first formation of a cutting under given circumstances is easily calculable, and so is the time within which the work may be effected. Experience has proved that there is for every soil a limit in depth beyond which it becomes more expedient to drift the required way, and construct a vaulted tunnel of sufficient dimensions, than to make an open cutting with the requisite slopes. Even when the first cost would not decide the question, the preference is nevertheless often given to the tunnel because of the greater security of constructed work.

Before proceeding to the consideration of the means of enabling opposite retaining walls to assist each other, it may be worth while to consider, whether retaining walls are generally constructed so as best to adapt their components to the duty to be performed. No one would place a buttress intended to resist the thrust of an arch within the springing walls, or under the arch whose thrust is to be resisted; yet in the construction of retaining walls, according to the common practice, the counterfort is placed on that side which receives the pressure, where its utility is very questionable, except to keep the retaining wall from falling back against its load, which, from the transverse section generally given to such walls, they would be apt to do, if not so propped up by their counterforts. Wharf and quay walls, and the revetment walls of military works, may require a face unbroken by projections; but this is not the case with retaining walls for roads and railways, where a long line of projecting buttresses would be unobjectionable, the counterforts becoming buttresses and merely changing places with the wall. On account of the common practice of battering the faces of retaining walls in curved lines, and of radiating the beds of the brickwork composing them from the centre of curvature in every part, the back of the wall must contain more setting material than the face, with the same quantity of solid brick, that is, if the work be bonded through. Counterforts must be built in the same courses, and consequently must have still thicker beds of compressible mortar than the wall; or the bond between the wall and its counterfort must be dropped, and the counterfort thus become utterly inefficient.

The retaining walls in the cutting upon the line of the extension of the London and North-Western Railway, from Camden Town to Euston Square, are, according to the common practice, built wholly of brickwork in radiating courses and with counterforts following their own contour. In this case the centre of gravity of the wall falls wholly behind its base, and the counterforts not commencing until the wall has reached one-third its height render it still more dependent for support upon the ground it is intended to retain. It is well known that these extensive walls, though furnished with all the collateral works necessary to protect them from exposure to undue influences, and although set nearly one-fourth of their height in the ground, failed to a considerable extent. A system of strutting with cast-iron beams, across from the opposite walls, as shown in fig. 1, to make each aid the other, was applied to meet the emergency; but this is limited to the upper parts of the walls.

Abutting struts from opposite walls, occurring at intervals only, leave the intermediate portions of the walls exposed to pressure from behind without support, unless these intermediate portions are so disposed as to communicate the pressure upon them to the struts. Hence a common retaining wall, abutted at intervals, would require these intervals to be more or less distant, in proportion to the strength of the wall between them. Instead, therefore, of a continuous wall on each side of the cutting, buttress walls should be placed at intervals, opposite to one another, and strutted apart at their toes by an inverted arch (as in fig. 2); and above, at a height sufficient for whatever traffic the cutting is to accommodate, by a built beam of brickwork, in vertical courses, supported on an arch, and prevented from rising under the pressure by an invert upon it, as in fig. 3. This built beam will then be, as it were, a piece of walling turned down on its vertical transverse section, and will resist any pressure brought upon it through the buttress walls, to the full extent of the power of such a wall built vertically to bear weight laid upon its summit; the pressure would be applied in the line of the greatest power of resistance, and there would be no tendency to yield, except to a crushing force. Let such transverse buttress walls, so strutted apart, with the road between them, be the springing walls of longitudinal counter-arched retaining walls, which, being built vertically and in horizontal courses, but arched in plan, against the ground to be retained, will carry all the force exerted against them to their springing walls, and the springing walls or buttresses will communicate, through the struts, the power of resistance of each side to the other, and thus insure the security of both.

This arrangement may be carried to any extent in height, by repeating the abutting beam or strut at such intervals as the thrust to be resisted and the strength of the buttress springing-walls may require.

To constructions thus arranged, any requisite power may be given, by altering the quantity of materials in each part, •—the length of the buttresses transversely of the cutting, the number of struts to each pair of buttresses, or the length of the compartments. The thickness of the buttresses should be in proportion to their height and length, and their length should be in proportion to the flatness and weight of the struts with their arches, and to the space in height between any two of them, as well as to the magnitude of the thrust brought to them by the counter-arched retaining walls. The inverted arch below and the built beam above must, of course, have sufficient substance to enable them to resist, without yielding in any direction, the pressure brought to them through the buttresses; and the retaining walls themselves must have substance given to them according to their height, to the pressure they are liable to receive from behind, to the length of the compartments, and to the extent of their flexure;—subject, of course, as to all these, to the nature of the materials, workmanship, and mode of structure.

The positive strength which such constructions should possess depends much, of course, upon the nature of the soil, and its susceptibility of being affected by external influences; but it depends, even in a greater degree, upon the manner in which the constructions can be applied to the ground they are intended to retain. A very slight power will retain at rest a body which the exertion of great force could not stop if once in motion, and a half-brick counter-arch, set in close contact with undisturbed ground, would hold safely up what three times the substance would not stop if there were space and opportunity for motion between the ground and the brickwork. It is impossible, therefore, to state precisely what is the least strength which the retaining constructions must have, but there can be no question that too much strength is better than too little, and it is generally cheaper to pay in materials than in labour to save materials.

The diagrams, figs. 4 and 5, represent a cutting 65 feet deep to the level of the rails. It is assumed that the ground at the top may stand for the first 15 feet at less than 2 to 1, and that it may, therefore, be cheaper to run out to that depth with slopes, leaving 50 feet from the rails, or about 52 feet in all, to be retained. As the bricklayer may follow up the excavator with bay after bay, his work lying mostly on the side and out of the way of the excavator, the latter would run out the spoil without interruption, his work being benched onwards and shored as he proceeded. As every compartment, with its buttresses, invert, abutting beams, and counter-arches is complete in itself, the ground being backed against the counter-arches as the work rises, the shoring would come out, and be sent on for use on the forward benches. The invert may be turned upon footings in half-brick rings, to get the largest quantity of solid resisting matter in the curved line. At a height from the surface of the rails sufficient for headway—assumed at 14 feet 6 inches—a 14-inch bonded arch is turned from buttress to buttress, springing from skewbacks on corbelled courses. Upon the back of this arch the abutting beam is built of brick on end and edge, bonded as a wall, with beds vertical and widening over the haunches of the discharging arch and under the similar inverted arch turned upon it; so that although the beam be in the centre but 21 inches deep, it presents an abutment at each end of three times that depth. The object of the invert over the abutting beam is to stiffen it, and to bring down and distribute the weight and pressure from the buttresses more effectually. The built beam, and its sustaining and stiffening arches, should be composed of particularly well-formed bricks of really good quality, set in cement or in some quick-setting mortar, that there may be no yielding to the pressure which must be immediately thrown upon this part of the construction. Another built beam, of greater depth, because of the absence of any inverted arch to stiffen it, is thrown across over the back of a semicircular arch, with its abutting ends extended in like manner.

To relieve the work from water, a drain being run along over the middle of the inverts, or side-drains being passed by ring culverts through the buttresses, drain-shafts are carried up at the backs of the buttresses against the springings of the counter-arches, to within a few feet of the surface. These shafts, being steened with open joints at intervals to admit drainage water and communicating with the draius below, prevent the possibility of water lodging about the backs of the counter-arches, or even in the ground itself. The drain shafts should be semi-domed with bricks set dry and covered in, and the walls also backed up with good clean gravel, through which the surface water may percolate and pass freely down to the shafts.

The constructions are assumed to be of brickwork, for the obvious reason that the cases supposed being clay cuttings, brick is the material which would be most economical. But if masonry be cheaper, it may of course be used with the same effect. Where a cutting intersects loose beds of laminated stone, and particularly strata inclined to the horizon, so as to be unsafe with the ordinary slopes, such constructions are available; and in Cases where the sides of the cutting will stand vertically or nearly so, as in chalk, it may be useful to apply similar constructions, though of slighter character, to check the separation and fall of masses from the precipitous sides. It is obvious, too, that these constructions present the means of security, when the stratum forming the base of any cutting is too weak to bear the weights of slopes, or of retained sides, without rising between them. Sheet-piling may be driven to any depth along the backs of the counter-arched walls so as to be retained at the head by the walls; and thus in effect the walls woùld be carried down to a safe depth, even through the weak stratum; whereas such piling at the toes of slopes is commonly found to be almost if not wholly useless, for the want of a stay to the head.

The ignitibility of timber, and the rapidity with which it burns when placed in circumstances so favourable to that effect as by its disposition in an erected building, have led to its prohibition for the purposes of the main enclosures of houses and buildings generally, in London, and in many of the larger provincial towns. It is possible, however, so to protect timber employed in the enclosures and for the internal partitions and floors of buildings as to render mere dwelling-houses practically incombustible. Whilst, however, the liability of timber to take fire and to burn may in a great measure be counteracted, and notwithstanding that this material combines the advantage of economy with security, stone and brick are undoubtedly better adapted for the main structure of a building. Brick or stone, or. brick and stone together, with a setting material, ought to be employed, but in such manner only as to be free from dependence upon other and less trustworthy materials. The most perfect erections as buildings are those in the composition of which this principle has been understood and fairly practised. If adventitious aid be given to brick or stone walls by foreign materials, the materials ought to be at the least harmless. Iron in bulk is not a proper substance to incorporate with walls because of its great expansibility by heat; but iron used in thin laminae, as hoop-iron laid in walls in the bed-joints of the brick or stone, cannot be productive of any bad consequences, while it is most beneficial in that form as a tie to the structure.

Bricks come ready shaped to the hands of the workman in a form the best adapted for the arrangement in the construction of a wall which, under the designation of bond, gives it such a degree of consistency that a weight placed upon the top is carried by the wall in every part throughout its whole thickness, and throughout a greater or less proportion of the length according to the height of the wall. Stone, on the other hand, comes to the workman without regular form; and with skill on his part to dispose and arrange the materials, good erections may be produced of rubble; for although the thickness of which walls may be built of rubble with safety will depend in a great degree upon the quality of the mortar, much depends also on the skill of the workman in bedding and bonding the stones. Under any circumstances, however, a wall so composed cannot safely be charged with heavy weights, or be exposed to the vibrating action of floors, until the mortar shall have indurated to some extent; whereas a wall of brickwork is secure by the horizontal bedding of the bricks, and by the effect of the transverse bond which the alternation of header and stretcher almost necessarily produces. Stone, again, may be dressed to any shape, and so as to mould it to every variety of construction with the smallest possible quantity of mortar or cement. From blocks with rough hammer-dressed parallel beds, up to the most complete and perfectly wrought parallelopipeds adapted to any arrangement of bond that may be best adapted to the structure,. and with combinations of rudely formed and perfectly formed pieces of stone, walls may be built of stone of greater strength than the best brick can be made to yield, whilst stone walls are liable to be inferior in every respect to brick-built walls of ordinary quality.

Some combinations of the two kinds of materials have the effect, however, of making a better wall than could be produced by the main constituent in the form employed alone. A stone-rubble or pebble built wall is greatly improved by one or two bonding courses of brickwork at short intervals; and a brick wall is improved and adapted for a higher purpose by thorough courses, at intervals, of good stone, wrought to bed and joint truly; whilst on the other hand, a wall substantially of stone-rubble or pebble, and faced with brickwork, is essentially an unsound wall; and in like manner a brick wall faced with wrought stone is liable to be weaker than the brickwork would have been without the stone.

With regard to the thicknesses of the walls of buildings, it is generally considered that these should be governed by the height of the structure; but they ought not to be determined by that condition alone. Chimney-breasts, or other buttress-like projections, built up with a wall, and extending to more than the thickness of the wall, make it in fact stronger in its transverse section, and justify less general thickness in the body of the wall, whilst window and other openings in a wall leave piers which ought to be of greater thickness than the mere height would require. But all returns, indeed, whether as chimney-breasts or as cross walls, built and bonded with a wall, tend to render unnecessary the full thickness which the height might require; whilst, as just intimated, the omission of portions of a wall for door and window openings should be compensated for by additional substance to the parts which remain. Walls subjected to undue action, such as that arising from slight joists tailed into them, or that occasioned by inclined timbers, as under galleries in churches, chapels, and theatres, require to be of greater thickness than they otherwise would; whilst it is quite wonderful to what great heights brick walls may be built with safety, if they are well built, and exposed to no other action than direct vertical weight. When, indeed, such walls stand upon a sufficient foundation, direct vertical weight without motion is a means of security to the walls so long as the weight is reasonably within the power of resistance of the materials to crushing pressure. The object to be looked at, therefore—the walls being honestly built—is, as before remarked, to make the weight to be imposed upon any wall act upon its solids vertically and steadily.

Floors upon girders, or framed to strong trimmers—the girders or the trimmer-joists running into and bearing upon the piers or solids of the walls—are far preferable to what are termed single floors, of which each joist runs into the wall. Girders as the basis of floors render plates in the walls wholly unnecessary, by depositing the weight in the right places, without requiring plates to carry it on from the weaker to the stronger places; and being of necessity stout and rigid, they form a fair tie and strut to the walls into which their bearing ends are tailed. Whether girders or trimmer-joists be employed for placing the weight of floors upon the walls of a building in the safest manner, the bearing timbers ought to be placed upon pieces of stone as templets built into the walls, and to be made to take a cog-hold of the templets, so as to enable them to tie and stay the walls by means of the cogs. It is by means of the girder bearing upon the solids of the walls, though with bad carpentry, that the French are able to carry up their soft, coursed-rubble, stone walls to heights that would certainly be unsafe if the walls were seamed with wooden plates, and shaken by floors of single joist; such, for instance, as a wall of a total height of say 85 feet, with a thickness of 18 English inches on the ground-floor and through six stories, or about 65 feet, and finished by a gable,—the basement being vaulted with walls about 20 inches thick. It is by means of the solidity given to the floors by the girders, and the solid bearings which the girders obtain, that the floors are able to carry the dead weight of matter which renders them practically fireproof, as described below, in addition to the moving weights to which the floors of buildings are necessarily exposed in use. We can and do frame floors most effectively by carpentry alone; whereas the French do the work so badly, that no important bearing is, or indeed may be, trusted by them to the framed joint—dog-nailed stirrup straps of iron being always brought in aid. But the common practice in England is to use single or unframed floors, which carry the weight and the vibration to which floors are exposed into the walls, over voids as well as over solids; while the French frame their floors to or upon girders, by means of which the floors are brought to bear upon the solids of the walls. The walls are thus not only less exposed to vibratory action, but are both tied together and strutted apart with better effect by the stout girders stiffened by joists than by joists which themselves requiro some foreign aid to stiffen them. Moreover, single floors of joists, unless trimmed at frequent intervals, when, indeed, they may be termed half-framed, are supposed to require plates of timber laid along the inside faces of outer walls and upon internal walls. This defect is avoided by French builders, who exclude all timber, except the bearing ends of girders, from their walls, and use framed floors.

When the walls of a building have reached their full height, the wall-plate comes into use legitimately—to cope the walls, in fact, and to form a curb as a base upon which to place the roof, which should deposit its weight, nevertheless, by means of its tie-beams upon the plates over the solids of the wall below, and which should, moreover, oversail, so as to cover and effectually shelter from the weather the enclosing walls also.

In setting forth the structural advantages derivable from the use of girders as the bases of floors, it may be necessary to repeat the warning already intimated against the use of girders of a material of uncertain strength, and of treacherous character when exposed to transverse strain. Cast-iron is of uncertain strength, mainly because of the imperfections which the most skilful founders, with the best materials and every appliance at command, cannot always avoid, and which are most liable to occur in the production of complex forms in long lengths; whilst careless founding and rapid cooling are contingencies connected with the production of cast-iron girders—which are necessarily long and complex castings. Cast-iron is treacherous, inasmuch as it is brittle and liable to be startled into fracture by impact trifling when compared with what it may have borne safely as a dead-weight. Proving long metal castings by straining them upon their transverse section does but aggravate imperfections, and leave the casting weaker; whilst no dead-weight proof is proof against blows or other action inducing vibration. It is only under circumstances which do not admit of concussive action upon the beam, or which prevent it from vibrating under any shock that may reach it, that cast-iron can be safely used in beams of long lengths to carry heavy weights, without some appliance to mitigate, at least, the imperfections which this substance exhibits. The application of wrought iron tension bars as soles to beams and girders of cast-iron would prevent the most serious consequences from attending the failure of the casting, if the beam were also prevented by binders, or by other sufficient means, from turning round when the blow produces an oblique fracture. Wrought iron girders can be and are now extensively used to carry floors, partitions, and even walls with safety.

Inasmuch as some soils are liable to change in form, expanding and contracting under meteorological influences, as clays which swell when wetted and shrink when dried, concrete foundations are commonly interposed upon such soils to protect the building from derangement from this cause; or rather, for that purpose walls of the cheaper material, concrete, instead of the more expensive brick or stone structure, are brought up from a level sufficiently below the ordinary surface of the ground. When concrete is used to obviate the tendency of the soil to yield to pressure, expanse or extent of base is required; and the concrete, being widely spread, should therefore be deep or thick as a layer, only with reference to its own power of transmitting to the ground the weight of the wall to be built upon it, without breaking across or being crushed. But when concrete is used as a substitute for a wall, in carrying a wall down to a low level, it is in fact a wall, wide only in proportion to its comparative weakness in the absence of manipulated bond in its construction, and encased by the soil within which it is placed.

The foundation of a building of ordinary weight is, for the most part, sufficiently provided for by applying what are technically termed footings to the walls. The reason for a footing is, that the wall obtains thereby a bearing upon a breadth of ground so much greater than its own width or thickness above the footing, as to compensate for the difference between the power of resisting pressure of the wall and of the ground or ultimate foundation upon which the wall is to rest. It will be clear from this, that if a building is to be erected upon rock as hard as the main constituent of the walls, no expanded footings will be necessary; if upon chalk, upon strong or upon weak gravel, upon sand, or upon clay, the footing must be expauded with reference to the power of resistance of the stratum to be used as a foundation; whilst in or upon made ground, or other loose and badly combined or imperfectly resisting soil, a solid platform bearing evenly over the ground, and wide enough not to sink into it, becomes necessary under the constructed footing. For this purpose the easiest, the most familiar, and, for most purposes, the most effectual and durable, is a layer of concrete, which may be formed so as to cover a surface large enough to obtain from the most yielding soil the amount of resistance to pressure required to support the weight of the intended building. It will be evident that upon a concrete foundation a footing or expanded base may or may not be required to a wall, according to the hardness of the concrete and the kind of wall to be built; but it is perhaps better to give the footing to the wall than to wait for the sufficient induration of the concrete to enable the wall to do without a footing; and better still, to lay the concrete of such height only with reference to the spread or extent of base beyond the toes of the footing, as the gravel of which the concrete is made would stand at in an uncombined condition. Concrete, indeed, is at all times more safely to be regarded as a substance to be placed as a layer, than as a substance to be set up as a wall; for although excellent erections as walls may be made of concrete—as erections in the same form may be made of tempered clay or of pisé-work—neither concrete nor tempered clay is to be regarded as a proper substance with which to form the lofty walls of buildings in towns. The use of lime concrete involves walls of a considerable thickness; Portland cement concrete, a stronger material and having the property of hardening rapidly, is more commonly used for thin walls. Several patents have been taken for erecting buildings with concrete walls by the construction of troughs formed of frames and movable boards or shutters. But considerable doubt exists as to the extent to which such walls can be built, as many have cracked, proved leaky, and shown other faults; whilst much economy does not result except where the work is very plain and straightforward, where little is spent on subsequent finish, and where the materials can be obtained at very little cost either for themselves or for carriage.

Construction for Protection against Fire.— Houses seldom take fire from common accidents, such as occur to the lighter movable furniture and to drapery; but, for the most part, from the exposure of timber in or about the structure to the continued action of fire, or of heat capable sooner or later of inducing the combustion of timber; and as the source is most commonly in defective gas-piping, or in some stove, furnace, flue, pipe, or tube, for generating or for conveying heat, or for removing the products of combustion, much of the real danger to buildings from fire would be prevented by avoiding that degree of proximity of timber to all such things as can lead to its combustion. With a view to lessen the danger to which buildings with timber in their structure are exposed from fire, it will be well to consider how far the timber and wooden fittings commonly used may be necessary either to the stability of the buildings, or to the comfort and convenience of the inhabitants. But it is not our intention to describe here the various modes of fire-proof construction, but only to notice the principles upon which ordinary buildings may be rendered nearly incombustible. So long: as danger of fire is brought to buildings through pipes and tubes, the necessity must be admitted of guarding the combustible materials used in buildings from any chance of becoming ignited. When heat is produced and passed through pipes in any manufactory, whether it be to act as power, or for drying or for warming, the fires used may be guarded, and the machinery which regulates the intensity of the heat to be transmitted may be under constant care; but even in such cases there can be no certainty that the heat shall not at some time arrive at the point of danger. But when heat is diffused throughout dwelling-houses by means of apparatus which is committed to persons unskilled in its use, and unconscious or careless of the danger which may arise from neglect, it seems impossible to lay down inflexible rules for distances from timber which shall render it safe from heated pipes. Twelve or fifteen inches may not be a greater distance than safety requires under some circumstances, whilst there are many cases in which the actual contact of such pipes with timber is hardly inconsistent with safety. When the air about heated bodies is not confined, as it would be within the timbers of an ordinary floor, a distance between the timber and the heated surface equal to the longest diameter of the tube or pipe will be found sufficient if the temperature of the pipe does not exceed that of boiling water. It is to be understood that a piece of wood will bear a powerful deadheat upon its sides for an indefinite period without igniting, unless a transverse section of the fibre, as at or around a live knot, or where a branch had been lopped, present itself to the action. It is by the end that a piece of wood exposed to powerful heat most readily ignites. The gases evolved in the substance of the timber by the action of heat applied to its surface, expanding as they are evolved, are thrown out by the pores among the fibres at the ends, if the ends are near enough to the action to allow of this effect, with less power than may be enough to obtain vent for the inflammable gases laterally.

The English Government, when it has legislated upon such matters, has generally confined itself to making provision that the enclosing walls of buildings should be formed of incombustible materials. In provisions regarding the least thicknesses of such walls, these were generally determined with reference to the height of the building, and to the area to be enclosed, as an indication of the probable lengths of the walls; and this both for the purpose of promoting safety of structure, and of checking the spread of fire from building to building. As, however, in most cases greater thickness is required in the side wall of an ordinary dwelling-house in a town to render its structure secure than is necessary to enable it to check the spreading of fire, such walls are frequently made of greater thickness than would be necessary to fulfil the objects which the Legislature has had in view, if the walls were not supposed to extend the whole length of the two longer sides of a parallelogram without intermediate cross or return walls. A solid, well-built brick wall, one brick or 9 inches thick, between two ordinary dwelling-houses of five or six squares in area each, will prevent the communication of fire through it from one to the other. But, in towns, ordinary dwellinghouses, which occupy each an area of five or six squares, are generally disposed iu plan as parallelograms, having their opposite sides 18 or 20 feet, and 28 or 30 feet respectively in length, and are seldom carried up to less height than 35 or 40 feet; and walls of such lengths and heights could hardly be deemed safe if not more than one brick thick. Consequently, a greater thickness has been prescribed as the least thickness of the walls of buildings of the sizes indicated. In the older Metropolitan Building Acts much greater thicknesses were prescribed for the walls likely to be the longer walls; whilst the only necessity for more than one brick rises from structural requisites, and not from any insufficiency of a wall of solid brickwork one brick thick as a means of preventing the spread of fire.

But the requisites of the structure would be as well fulfilled by one-brick walls upon the long sides as by 1⅜ brick walls, if the ordinary internal cross partition for dividing a house into front and back rooms were built of brickwork abutting upon, and at right angles to, the longer walls, and carried up coursed and bonded with them. That is to say, party-walls of one brick or 9 inches in thickness, connected at their-ends by l∣-brick or 13-inch front and back walls, and at or about the middle of their length by other 9-inch cross walls, would be at the least as strong as 1J-brick party-walls, though connected in the same manner at the two ends, but without the abutting and connecting cross wall of brickwork. Instead, however, of such internal cross walls, hollow partitions of timber are commonly used in all stories above the basement story; and it is by these partitions, and by the light and highly inflammable wooden stairs, that fire extends itself rapidly throughout ordinary dwelling-houses; whilst the substitution of a brick wall for the cross timber partition would in most cases justify the abatement of a half brick of the thickness otherwise necessary to party-walls, and give an indestructible internal support to the floors, whereby also one of the means by which fire travels rapidly through a house would be removed. It is true that there must be openings as doorways, and fittings in them for doors, in such internal partition wall; but the wall could not carry fire up from floor to floor through its own heart, as the hollow wood-lathed quartering partition carries it. Doors and shutters, and door window linings, in and against brick or stone walls, may take fire and burn in any story of an ordinarily built dwelling-house, without carrying itibeyond the story in which the fire occurs; for a plastered ceiling of the most common description will resist the action of flame upon its surface for a long time, and plastering of really good quality, though upon wood laths, will keep fire off from the joists by which it is held up, almost without danger, so long as the fire acts upon the face only of the plastering. If, however, fire reach the joists through the agency of hollow quartering partitions, the enemy has turned the flank of the plastering, and the floors and skirtings above and behind it taking fire, the building almost inevitably falls a prey to the flames. Any step, indeed, from the hollow quartering partition ' towards a solid wall is a step towards security. A brick wall is, perhaps, the best internal partition for all the purposes of strength and security from fire; and in small houses, which will not afford the expense of 9-inch walls, half-brick walls with 9-inch jambs at the doors, and short 9-inch piers on alternate sides of the partition, at intervals of 3 or 4 feet in length, will give sufficient strength; but even quartering partitions, if based upon brick walls, may be rendered nearly proof against fire by brick-nogging them, especially if care be taken to fill in with brickwork between the joists over the head of one partition and under the sill of another, as well as between the timbers of the partitions. Filling in between the joists, and up as high as the skirtings go, will do something, indeed, towards diminishing the dangerous tendency of even lathed and plastered timber partitions; whilst the adoption of the plan now commonly practised in Paris, in forming not only internal partitions, but the rearward external enclosures of buildings, would secure to the structure the structural efficiency of timber on end in carrying weight, and give the solid and incombustible character of a brick or stone wall to a partition or enclosure which is structurally of timber. The plan referred to is, to frame and brace with timber quarterings much in the manner practised in England, except that the timber used in Paris is commonly oak, and is generally seasoned previously. The framed structure being complete, strong oak batten-laths, from 2 to 3 inches wide, are nailed up to the quarterings horizontally, at 4, 6, or even 8 inches apart, according to the character of the work, throughout the whole height of the enclosure or partition; and the spaces between the quarterings, and behind the laths, are loosely built up with rough stone rubble, which the laths prevent from falling out until the next process has been effected. This is, to apply a strong mortar, which in Paris is mainly composed of plaster of Paris, which is there of excellent quality, laid on from both sides at the same time, and pressed through from the opposite sides so that the mortar meets and incorporates, embedding the stone rubble by filling up every interstice, and with so much body on the surfaces as to cover up and embed also the timber and the laths—in such a manner, indeed, as to render the concretion of stone and plaster, when thoroughly set, an independent body, and giving strength to rather than receiving support from the timber.

The English brick-nogged partition is, in point of structure, nothing without the aid of timber. The plastering is merely spread upon the surfaces of brick and wood, and is fragile in the extreme, and always liable to crack and drop off. This lathed and plastered partition is composed of the hollow framework of the timber quarters, with two slight thicknesses of mortar, as plastering, hung upon slighter laths, over and between which the flaccid mortar forms a key for itself; but all necessarily depends upon the timber, and fails with it wherever decay or fire may destroy it.

Only second in importance to the internal partition as a source of danger, or as a means of safety, are the stairs; and the stairs are second in importance only when the partitions are made to carry the floors of the several stories. In England, and in London particularly, even when the steps and intermediate landings are of stone, it is but too common to find the passage from the street door to the foot of the stairs, and the floors which connect flight with flight at the several landings, either wholly of wood or of slight stone paving laid upon wooden joists or bearers. Any stone paving upon wooden joists will certainly retard the action of fire upon the joists, especially if assisted by a well-plastered ceiling; but in this, again, if the floors be not formed of wholly incombustible materials, the French practice as to floors would be better than ours.

In Paris stone stairs are far less common in modern houses than they are in London in houses of corresponding character and date; but wooden staircases in Paris are rendered almost as safe as common stone staircases are in England, by a process similay in character to that applied to partitions and enclosures. The result is an almost incombustible structure. Wooden staircases formed between brick or stone walls, or between partitions of the kind above described as commonly made in modern buildinge in Paris (that is, filled with a solid mass of concreted rubble), may perhaps be set on fire, but they can hardly burn.

It has been remarked that a mere plastered ceiling will resist the action of fire for a long time, although the plastering be upon wooden laths, and the laths nailed to joists of timber; and as fire does not readily act downwards, flooring boards may take fire from above without any immediately serious consequence to the joists under them, so long as there is no access of air from below. But the English indoor plastering upon laths is commonly of the most fragile kind, and the slightest weight falling upon the back of a ceiling will make a breach through it, whilst the floors are commonly of deal laid upon fir joists, and are exposed to the action of fire from below directly the lathed and plastered ceiling has failed; if, indeed, the fire have not found its way to the joists under the flooring boards by the hollow lathed and plastered quartering partitions. In the timber enclosures and partitions, which economy induces the Paris builder to introduce as substitutes for walls, the timber is so embedded in and made part of a solid concrete, as to be protected from almost every casualty of which it is susceptible. But the French render their floors also so nearly incombustible as to leave but little to desire in that respect, and in a manner attainable with single joists, as well, at the least, as with joists framed into girders. According to their practice, the ceiling must be formed before the upper surface or floor is laid, as the ceiling is formed from above instead of from below. The carpenters’ work being complete, strong batten-laths are nailed up to the under sides of the joists, as laths are in England; but they are much thicker and wider than our laths, and are placed so far apart that not more, perhaps, than one-half of the space is occupied by the laths. The laths being affixed—and they must be soundly nailed, as they have a heavy weight to carry—a platform, made of rough boards, is strutted up from below parallel to the plane formed by the laths, and at about an inch below them. Mortar is then laid in from above over the platform and between and over the laths, to a thickness of from 2∣ inches to 3 inches, and is forced in under the laths, and under the joists and girders. The mortar, being gauged, as plasterers term it, or rather, in great part composed of plaster of Paris, soon sets sufficiently to allow the platform to be removed onwards to another compartment, until the whole ceiling is formed. The plaster ceiling thus produced is, in fact, a strong slab or table, in the body of which the batten-laths which hold it up are incorporated, and in the back of which the joists, from which the mass is suspended, are embedded. The finishing coat of plastering is then laid on. Such a ceiling will resist any fire that can act upon it from below, under ordinary circumstances; and it would be difficult for fire to take such a hold from above as to destroy the joists to which a ceiling so composed is attached, the laths and the under side of the joists being alike out of its reach; and consequently such a ceiling alone would diminish the danger from fire, although the floor above the joists were laid with deal boards.

A boarded floor, however, in Paris is a luxury not to be found in the dwellings of the labouring classes, nor, indeed, are boarded floors to be found in any dwellinghouses but those of the more costly description. Whether the proposed surface is to be boarded or not, however, the flooring joists are covered by a table of plaster above, as completely as they are covered by a plaster ceiling below. Bough battens, generally split and in short lengths stout enough to bear the weight of a man without bending, are laid with ends abutting upon every joist, and as close together as they will lie without having been shot or planed on their edges. Upon this rough loose floor, mortar of nearly similar consistence to that used for the ceilings is spread to a thickness of about three inches; and as it is made to fill in the voids at the ends and sides of the floor-laths upon the joists, the laths become bedded upon the joists, whilst they are to some extent also incorporated with the plaster. The result is a firm floor, upon which, in ordinary buildings, paving-tiles are laid, bedded in a tenacious cement. It must be clear that the timbers of a floor so encased could hardly be made to burn even if fire were let in between the floor and ceiling. But it has been already stated that the practice of making these incombustible floors is connected with the use of walls which have no timber laid in them bedwise, and that the timber enclosures employed instead of walls, and the internal partitions, are rendered practically incombustible, whilst the wooden staircase which economy dictates to the Parisian builders—the freestone which is used in building walls being altogether too soft for the purpose— is also rendered, in the manner already shown, almost unassailable by fire.

It may be remarked with reference to the employment of any substance such as cinder, being of the nature of pozzuolana, or volcanic scoria, in mortar, to form a floor in the manner above described (about 3 inches thick), that as all such mortars expand in setting, the walls of buildings may be forced out by the expansion of the plaster floors, if the whole surface of the floor in any story be at once covered with the mortar. A margin of 4 or 5 inches on every side should be left void until the expansion has taken place, when the floor may be completed with an assurance of close joints, and without injury to reasonably stable walls.

When a boarded floor is required, as the surfaces of the true joists lie under the mortar, a base for the boards is formed of what English carpenters would call stout fillets of wood, about 2⅜ inches square, ranged as joists, and strutted apart to keep them in their places, over the mortar table, to which they are sometimes scribed down, and that to these fillets, or false joists, the flooring boards are secured by nails; so that in truth the boarded floor is not at all connected with the structure of the floor, but is formed upon its upper coat of plaster. The wooden floor thus becomes a mere fitting in an apartment, and not extending beyond the room the floor might burn without communicating fire to the stairs, even if the stairs were readily ignitible.

The practice now in Paris, in respect of floors, is to form the structure of wrought iron joists rolled to the form known with us as I, T, and Z iron, and to fill in with the same strong plaster between, below, and above the iron, and so to form a slab of plaster from 6 to 8 inches thick, according to the bearing and the depth of the iron bars— the bars being enveloped in the plaster; and the ceiling is formed as before described by laths resting on the lower flanges. In order to lighten the weight of the solid plaster, earthen pots have been placed between the joists and the spaces filled up with the mortar.

The necessity which arises with us of dividing the upper stories of houses into more rooms, as bed-rooms, than are commonly required in the lower stories, will be made an objection to any process that would render the partitions heavier; but it is not in the upper stories that the lathed and plastered partition is most dangerous in respect of fire. Generally the stairs may be enclosed by solid partitions throughout almost the whole height of an ordinary dwellinghouse without occasioning any inconvenience as regards the greater weight of such a partition; and generally, too, the partition which divides the front from the back rooms of such houses may be carried up throughout the whole height of a house without removing the bearing, if the house be judiciously disposed. But even if a partition rest upon a beam or girder, a very slight addition to the scantling of the timber will make up for the additional weight which the filling in of the partition would involve, if the materials of the core be well chosen; and it is well known that a piece of timber placed over a void as a bressummer, and carrying a wall, resists the action of fire for a long time, and the longer if it be of oak or other hard wood. It is not necessary, however, that the timber employed in parti-tionβ and enclosures should be of oak; though it is desirable that main bearing timbers, in situations which render them most liable to be exposed to the action of fire in the event of casualty, should be of such timber rather than of fir; but the quarterings, or partition timbers, which the plaster concrete wholly encases, may be of fir as safely almost as of oak.

The core used in Paris consists for the most part of chips and spalls arising in the process of dressing the soft freestone which is the main constituent of the walls of most buildings in that city. Almost any hard material, however, will furnish rubble fit for the purpose, which must be angular and irregular in form, so as to allow the mortar to pass freely through the rubble, and embed it all. Rubble of brick material, as broken burrs, or even of old bricks freshly broken, will answer very well; but if brickbats or shreds of plain tiles be used, care must be taken in packing not to bring flat beds together, or the mortar will not pass through and make a perfect concrete. Rubble of almost any kind may be used; but the kinds of stone which are themselves concretions, and present rough surfaces upon the fracture, are the best, while schistose or scaling slaty stones are the worst for the purpose. But there is no better substance for coring partitions upon the plan described than clay burnt into a kind of brick rubble.

The same process applied to external enclosures will justify the use of timber in their structure in situations and under circumstances in which it may be properly prohibited when the timber is merely lathed and plastered, or even brick-nogged, for brick-nogging adds nothing, as already remarked, to the strength of a partition or an enclosure, but rather takes from it, being itself a source of infirmity. But chimneys and their flues, with their congeners, stoves and furnaces, ought not, under any circumstances, to be formed in an enclosure in which timber is employed as a part of the structure.

Under some circumstances, again,—that is to say, when any street of a town is so wide and the buildings to be built fronting it are to be of such small elevation, as to make the communication of fire from one side to the opposite side practically impossible, if the buildings adjoining laterally are effectually separated from one another by sufficient walls, party or otherwise, and these project before the outside faces of the front and back enclosures so as effectually to prevent fire from passing round them,—the temperature of dwelling-houses may be much more easily maintained and regulated if the outside surface be boarded. Weather-boarding is a safe and economical, as well as a neat, wholesome, and equable outside casing for the fronts of a dwelling-house, if the boarding be backed up solidly, and the timber quarterings necessary to secure it be properly filled in between and behind with brick or stone work, or with rubble and concrete in the manner already described. Brickwork builds up badly with the raking braces of timber-framed enclosures, and the concrete described would not be so perfect with weather-boarding on one side as if the mortar were thrown in from both sides; but raking braces are less essential to enclosures which are filled in and backed with a heavy body of brickwork or concrete, than when mere lathing or even brick-nogging is to be employed on the inside. A 9-inch brick wall may, indeed, be very well built up with framed quarterings without raking braces, if the work be built between and around the quarterings, carrying, that is to say, the inner half-brick before the inside faces of the chartering, and so as to show on the inside a plain brick wall.

Building Trades.— The artificers whose trades properly belong to the builder’s business are the digger or excavator, bricklayer, mason, sawyer, carpenter, joiner, cabinetmaker, slater, plumber, plasterer, modeller, carver, glazier, smith, founder, ironmonger, gasfitter, painter, and decorator. In this order the works of the trades will be described, and we now proceed to the ordinary routine of the practice of building. The two publications which should be noticed here as comprising more detailed references to these trades are Gwilt’s Encyclopaedia of Architecture, 8vo, 1869, edited by Wyatt Papworth; end Cresy’s Encyclopaedia of Civil Engineering, 8vo, 1861,—these will not, therefore, be noticed in the list at the end of each trade.

Foundation.— The architect having furnished the specification and working-drawings of his design, the first step is to prepare the foundation; and as this relates to the bricklayer as well as to the mason, we say what is necessary respecting it here. Much in this particular, it is evident, must depend on localities. It is not of so much importance that the ground be hard, or even rocky, as that it be compact, and of similar consistence throughout; that it be so constituted as to resist entirely and throughout, or yield equally to the superincumbent weight. But in the ordinary processes of building little requires to be said of the artificial preparation of foundations beyond the notice of jt already given. When a good, hard soil is easily accessible, as solid gravel, chalk, or rock, we have nothing to do but to remove the surface mould, dig to the sound bottom, and at once to put in the footings. On softer ground it was usual to employ footings at least double the width of the wall, and frequently more; but since the invention, or rather revival, of the use of concrete, this is seldom or never done. In this case, or when the ground is a deep clay, be the material used what it may, it should at least go so deep as not to be affected by change of temperature, or the rising and falling of springs, as the alternate shrinking and swelling of the ground must affect the building. Frost seldom penetrates a foot into the ground in this country; but in clay soils, fissures, the consequences of drought, are found 3 feet and more in depth. The basis should, therefore, be below this point in such a stratum. If the ground be springy, it should be drained, if possible; if not, a foundation should be made with concrete as low as the lowest level of the water; or if very deep or boggy, piles must be used. The plan of building on sleepers and planking, so common some years ago, is very bad, as they rot after a time, and the building settles in all directions, as the greater weights crush the decayed timbers sooner thaιi do the lighter portions of the building. Where ground is alternately wet and dry, the best timber soon decays; even piles should always be kept in the water. The use of concrete, except in very peculiar cases, has entirely superseded every other artificial foundation. It may be defined as a sort of rough masonry, composed of broken pieces of stone or gravel, cemented together with lime prepared in various ways, and thoroughly mixed with it, and not laid by hand but thrown at random into the trenches, to form the depth required.

Any hard substance, broken into small pieces, will make good concrete. That most used is gravel, or ballast. This should not be too fine, as the sand which may be in it will mix with the lime and form a sort of mortar, assisting to cement the stones together. If broken stones or masons’ chips are used, it is desirable to add some sharp sand with them. The general rule is, that no piece of stone should exceed a hen’s egg in size. In this country the lime is generally ground, which is bad, as the core or unburnt portion is ground up with the good lime. About one-sixth part of lime is generally used; chalk lime should not be used in a damp situation. It is mixed with the ballast by scattering it among the stones, and turning it all over with a shovel, water being at the same time thrown upon the mass. It is then, while hot, filled into the trenches, sometimes by shooting from stages erected for the purpose C or 8 feet above the work; but this process has been very justly censured as uncertain by eminent engineers, who prefer to put it in layers of not more than one foot in thickness, and to level each course, ramming it down thoroughly. When the lime is too hastily put into the trenches, and has not had time to be thoroughly slaked, the process will continue, and the mass will puff or swell and sometimes cause considerable mischief. Wing walls of bridges have been thrust out by this means. To make a solid concrete all the interstices of the gravel should be filled with the sand, and the lime and the water will be absorbed without any increase of bulk. In France the lime is first made into a paste, and the mixture is then called béton, not concrete; this is a more scientific process for obtaining a sound substance. In some experiments made by the Architectural Publication Society, where the materials were carefully mixed, no change took place in the bulk; but some experimentalists, practical men, and writers differ on this point, and assert there is a loss of one-seventh in bulk when set. The lime, if it can be procured, should be hydraulic; and concrete is much improved by the addition of the volcanic sands. French authors recommend, as good proportions, one-fifth hydraulic lime, one-fourth pozzuolana, one-eighth sharp sand, and the rest broken stone or gravel; or 20 per cent, hydraulic lime, the same of trass, the same of sharp sand, 15 per cent, of gravel, and 25 per cent, of broken stone. Perhaps the very best concrete is made of a simple mixture of gravel, sand, and Portland cement. It is unnecessary to enter into the details of foundations in water, as this but seldom comes within the ordinary builder’s province.

Digger or Excavator.— The digger works with a pick-axe and a spade or shovel. With the pick-axe he breaks down the soil if it be hard or very stiff, and throws it out with the shovel; but compacted sand and alluvial soil are spitted and thrown out with the spade alone, without previous breaking down. When rock occurs in a foundation, the assistance of the quarryman is requisite to cut through or blast it, as the occasion may require. The digger should be required to produce a perfect level in every direction, and especially in trenches for walls; fior may this be done by replacing loose matter, but the level must be produced on the solid or undisturbed bed. A good excavator will dig and throw out, of common soil, into a basket or wheelbarrow, 8 or 10 yards per diem; but of stiff clay or firm gravel not more than 6 yards.

When the excavation has to be dug to a depth about the height of a man it will, be necessary to strut the ground to prevent its falling in, especially if it be of a sandy, loose, or watery nature. This is done by placing on each side of the cutting upright planks against the soil, which may be either open or close, according to the quality of the soil, and against these one or more horizontal waling pieces secured by horizontal cross pieces or struts, and wedging up as necessary. On these struts are formed the landings or stageβ on which the lowest workman throws the soil he digs up, which is then again thrown up by a second man to another stage or to the surface, according to the depth. Sometimes the soil is hoisted in baskets or tubs raised by a windlass worked by hand, or by a horse-run. When the work has been executed for which the excavation was prepared, the digger has to fill in over and around it, carefully ramming the soil to prevent inequalities on the surface by the soil sinking, and to prevent water soaking in which might affect the foundations.

Brickwork,

The tools and implements employed by the bricklayer are the trowel, plumb-rule, rod, level, square, bevel, line-pins and lines, raker, jointer, crow-bar, pick-axe, and rammer, together with a hod and spade for his labourer. Besides these there are sundry others, as an axe, saw, and rubstone, used in ctutting and gauging bricks, and some which are peculiar to tiling and paving. A pug-mill and screens for mixing and tempering mortar, and tubs and pails for water, are alsoauxiliaries of great importance.

In ordinary practice the bricklayer’s scaffolds are carried up with the walls, and are made to rest on them. Having built up the walls as high as he can reach from the ground, he plants a row of poles, which vary in height from 30 to 40 and even 50 feet, parallel to and at a distance of about 4 feet 6 inches from the walls, and from 10 to 12 feet apart. To these, which are called standards, are attached by means of cords other poles called ledgers, horizontally and on the inside, with their upper surface on a level with the highest course of the wall yet laid; and on the ledgers and wall short transverse poles, called putlogs or putlocks, are laid as joists to carry the floor of scaffold boards. These putlocks are placed from 4 to 6 feet apart, according to the length and strength of the scaffold boards; and the ends which rest on the walls are carefully laid on the middle of a stretcher, so as to occupy the place of a header brick, which is inserted when the scaffolds are struck after the work is finished. On the floor of the scaffold thus formed the bricklayer stands, and the materials are brought up ladders to him by labourers in hods from the ground below; or they are hoisted up in baskets and buckets by means of a pulley-wheel and fall; or by the horse-run, which is more generally used, formed of a level pathway in which the horse moves, drawing up the load by the intervention of snatch blocks and guide wheels; or by the now usual hoisting-machine, worked by men, horses, or steam-power. The mortar is placed on ledged boards about 3 feet square, at convenient distances; and the bricks are strewn on the scaffold between the mortar boards, leaving a clear way against the wall for the bricklayers to move along unobstructedly. The workman then recommences the operation of bricklaying, beginning at the extreme left of his course, and advancing to the right until he reaches the angle or quoin in that direction, or the place where his fellow-workman on the same side may have begun. Thus he goes on with course after course until the wall is as high as he can conveniently reach from that scaffold, when another ledger is tied to the poles, another row of putlocks laid, and the boards are removed up to the new level. The ledger and most of the putlocks, however, remain to give steadiness to the temporary structure, and so on to the full height of the wall, the poles being pieced out by additional lengths as may be required. If a scaffold be very much exposed, and run to a great height, it must be braced. This is done by tying poles diagonally across on the outside to the standards and ledgers, and it may be further secured by tying the ends of some of the putlocks to the ledgers; but an outside scaffold should never be attached in any way to the building about which it stands. A scaffold should never be loaded heavily, as well on account of the work as of the scaffold itself; for the putlocks resting, as they do, on single bricks, in a green wall, they exert an injurious influence on it, which every additional pound weight on the scaffold must necessarily increase, and the putlocks themselves are liable to be bent or broken. A constant and steady supply of bricks and mortar on the part of the labourers, without overloading the scaffold at any one time, should be strictly required.

The suspended scaffold is a very ingenious contrivance, by which pointing and other external repairs of a house can be performed at a comparatively small cost, and without interference with the thoroughfare. The front can also be painted by the same means. Although known at least before 1825, it is only of late years that this scaffold has been much used. A couple of planks are secured side by side to form a platform, which is guarded by a railing all round to prevent the workmen falling off. To iron bands are secured pulleys and ropes, passing over other pulleys made fast to two or more beams projecting out of the upper windows, or secured to the roof-timbers, by means of which the workmen employed can raise or lower the scaffold to any position where it is wanted to get access to the work to be done.

Brickmaking.— The manufacture of bricks forms the subject of a separate article. See p. 279 of the present volume.

Mortars and Cements.— A few observations on the composition of mortars and cements for bricklaying will be necessary here. Mortar is of two kinds,—common mortar, or that mixture of lime and sand ordinarily used in building; and hydraulic mortar, or that which will set under water. Cement is a name given to the produce of certain argillaceous stones, after calcination, which will set rapidly in the air, becoming a hard adhesive substance in a short time, and will also set under water, both without admixture of any other substance. The name is given, too, to certain artificial imitations of these substances, possessing the same properties; and besides, to various bituminous or oleaginous compositions, used in building for similar purposes.

Pure lime, which is an oxide of a metal called calcium, does not exist in a natural state. It is, however, found abundantly in the conditions of carbonates and subcarbonates, in chalk, and in the various other descriptions of limestones. Its chemical qualities and analysis will be described under the proper headings in this work. Limes are generally classed, since the publication of the work of Vicat, as—(1) rich limes, (2) poor limes, (3) limes slightly hydraulic, (4) hydraulic limes, and (5) eminently hydraulic limes. In treating of mortar we have to deal with the first two of this division. The first operation is to drive off the water, which all limestones contain in a greater or less degree, and the carbonic acid gas, which is done by calcining or burning in a kiln at red heat; this must be kept up for several hours, care being taken to avoid any approach to vitrification. By this process it is slightly diminished in bulk, loses nearly half its weight, and becomes caustic lime. The lime is next converted into a hydrate by a process called “slaking,” or throwing pure water over it from time to time till it hisses and cracks with considerable force and some noise, gives off a large quantity of hot vapour, and falls into a powder. The rich limes, which are the purest oxides of calcium, increase to double their bulk in the process. The poor limes swell to a much less degree. The hydrates thus formed absorb water, and easily take the form of a paste. They contain rather less than one-third water to two-thirds lime. In this state, if treated with pure water, frequently renewed, every particle of the rich limes, and very nearly the whole of the poor limes, will be taken up in solution. In the process of slaking too much water should not be used, as it “drowns” the lime, according to the expression of the workmen. When in the form of paste it begins to absorb carbonic acid, which is always present in air in considerable quantities, and gradually to crystallize again, and so to harden. If the air be excluded from the hydrate of pure lime, it may be kept for almost any length of time. Alberti (lib. ii. cap. 11) says that he once discovered some in an old ditch, which from certain indications must have been there 500 years, and was as soft as honey or marrow, and perfectly fit for use.

The rich limestones give a white lime, which easily slakes, and increases in bulk; but it is curious that though the stones differ so much in outward appearance and in texture, the lime, if they be well burned, is the same. The softest chalk and the hardest rag-stone or marble yield an equally good lime, the calcium which they contain being the same mineτah But as chalk generally contains water, irregularly distributed in some places and not in others, and as it does not exhibit the change that marble or stone does, it is frequently unequally burned, and therefore slakes imperfectly. It is said by Higgins (Mortars and Cements, p. 29), however, that lime made from chalk absorbs carbonic acid more rapidly than that made from stone; but experience does not seem to warrant this conclusion. Poor limestones are those which contain silica, magnesia, manganese, or metallic oxides. In consequence of this they are more liable to vitrify in burning, and do not slake so freely. The lime is generally of a browner colour than that from rich limestones, which is said to be a proof of the presence of the above-named metallic oxides. If, however, they be ground so as to facilitate the slaking of every particle, and if used immediately being made up, poor limes produce a mortar which becomes harder than that from the rich limes, and which resists water better. In fact, works where the latter have been used have been found to fail .entirely by the action of running water, which, as before has been said, will continue to remove the whole of a rich lime particle by particle.

It is found that the mixture of some kind of hard matter in particles or granules facilitates the setting of mortar, and renders it harder and more adhesive than when used alone, besides the saving of limestone and expense of burning. The harder this material and the sharper the particles the better, as the brick or stone has always some irregularities on the surface, into which these angles or sharp points may enter, and form what is called a key. The substance most generally used is sand, which is classed as riversand and pit-sand. The former is usually preferred, as it is more free from earthy matters, particularly soft loams or clay. Mortar made with sand containing one-seventh or one-eighth part of fat clay moulders in winter like marl,—a circumstance which proves the propriety of freeing from clay the sand used in mortar. If pit-sand bo used it should be well washed. Scarcely any material is better than crushed quartz, or flint, from the sharpness of the angles of the particles; in fact, it is said that very sharp sand, with an inferior lime, will make a more adhesive mortar than soft sand with the best lime. The practical mixing of mortar will be noticed further on. Where sand is scarce, other materials are sometimes used, the principal and cheapest of which is burned clay. The Romans used this extensively in the form of pounded tile. At present the custom is to throw up clay mixed with fuel in loose heaps, to burn it slowly, and then to grind it in a mill with a proper quantity of lime. The French writers at one time asserted that burned clay, if not equal to pozzuolana, was very nearly so; and large quantities were used as hydraulic mortars at various public works. Where the water was fresh, as at Strasburg, the work stood very well; but where these mortars were exposed to the action of sea-water, they failed and went to powder in three or four years. Vicat gave great attention to the subject; and though he attributed much of the fault to the imperfect carbonization of the materials, it appears with but little doubt there is some inherent difference between the pozzuolanas and other volcanic products and those produced artificially. After long investigation, Vicat was of opinion that this failure was due to the quantity of hydrochloride of magnesia always present in sea-water; but in what way this affected the burned clay and not the volcanic products he was unable to explain.

A very excellent mortar, much used by engineers in tunnels, is composed of one part of moderately hydraulic lime, one part of coal ashes, one part of burned clay, and two parts of sharp sand. The vitrified refuse of furnaces, called slag, and the scoriae from the iron-works, have also been crushed and used instead of sand; and with lime, slightly hydraulic, produce good mortar. The former is preferred to the latter, as having sharper and harder particles, and containing much less iron. Coal cinders have been used, and seem to have some hydraulic properties; they should, however, be employed with caution, for it is considered they make the lime “short.” Wood cinders are too alkaline to be used with safety.

The vitrified and calcined products of volcanoes make most excellent materials for mortars, particularly where required to be eminently hydraulic. The principal of them is the pozzuolana, which abounds in Italy. It is called so from being found in great abundance at Pozzuoli, near Naples, and is, in fact, the basis of all the best Roman mortars, ancient as well as modern. It is usually sent to England from Civita Vecchia. It varies in colour from reddish brown to violet red, and is sometimes greyish; it has a roughly granulated appearance, and sometimes resembles a cinder in texture, and has frequently a spongy appearance. Acids have little effect on it, and it is not soluble in water. Λ similar earth is found in the centre of France. But one long known in this country comes from the village of Brohl, near Andernach, on the Rhine; this is called tarrass or tras3. These materials have a wonderful effect in rendering even the rich limes eminently hydraulic, and in less proportions improving the hydraulic limes. Vicat says, these mortars begin to set under water the first day, grow hard in the third, and in twelve months are as hard as the bricks themselves. The mixture of common lime with these materials, according to the French writers, should be 1 of pounded lime to] 2⅜ of pozzuolana, or to 2 of trass; or 1 of lime to 1 of sand and 1 of pozzuolana.

In addition to the hydraulic limes, which have been thus described, there is a peculiar class of stonps, which, when burned and pulverized, may be used as mortar, without admixture of sand or any similar substance; and which will not only set rapidly under water, but will acquire an unusual degree of hardness and tenacity. These are called natural cements. Mr Parker is supposed to have been the inventor; at any rate, that gentleman took out a patent about sixty years ago for what he called Roman cement. His materials were the argillo-calcareous nodules, or septaria, found in the Isle of Sheppey, and commonly called bald-pates. They contain about 70 per cent, of carbonate of lime, about 4 per cent, of oxide of iron, 18 per cent, of silica, and 6 or 7 per cent, of alumina. The process is simply to break the stones into small pieces, and burn them in running kilns with coal or coke; they are then ground to a powder, and headed up into casks for use. The success of Parker’s cement led to experiments in other places, and the same process was carried on with other argillo-calcareous nodules, as the septaria at Hawick; those in Yorkshire, which produce the cement called Atkinson’s; and those in the Isle of Wight, which produce the Medina cement. Similar substances were also discovered, and the same processes carried on in France and in Russia. All these cement-stones effervesce with acids, and lose about one-third of their weight in burning. Parker considered that the more the stones were burned short of absolute vitrification the better; but this is not the practice in the present day, though, no doubt, sound in theory. When taken from the kiln these stones will not slake without being pulverized; and if kept dry, and not exposed to the air, the cement will be good almost any length of time; but it rapidly absorbs both water and carbonic acid if not carefully closed up, and falls back into a state of subcarbonate, from which it is said it may be recovered by fresh burning, but it is doubted whether it is ever so good as on the first calcination. The great utility of these cements, and the expense of obtaining the stone, induced manufacturers to endeavour to discover some method of making an article by artificial means which should resemble the natural cements. Mr Frost seems to have been the first who attempted it on a large scale; but though he was assisted by the science of General Pasley, the results did not come up to the expected standard. Of course, the object was to produce an argillo-calcareous substance containing the same chemical qualities as the natural nodules, which might be burned in kilns as they are. The attempt to combine argil in the form of burned clay, to be mixed with lime instead of pozzuolana, had partially failed, as has been stated above. The experiments conducted by General Pasley, and by Vicat at Meudon in France, were all based on the principle of mixing together, in a mill, with a quantity of water, masses of chalk and clay, just as the brickmakers do for the production of malm bricks, but in the proportion of about four of the former to one of the latter. The fluid mixture is run out into shallow receivers, and when dry is cut into small blocks or lumps, and burned exactly as the natural nodules are. The difficulty was to give the materials the full degree of calcination short of vitrification. A successful result seems to have been at last attained by the inventors of the Portland cement, so called from its near resemblance to Portland stone in its colour. It not only possesses the property of setting more quickly, and has greater powers of cohesion than the natural cements, but it may be used with a superabundance of water in the form of grout, which they cannot be; above all, it seems to resist the action of sea-water beyond all others; and it is proof against water when used as a mortar in setting brickwork, and in the composition of concrete for foundations. It also forms a very superior cement for plasterer’s work. A prepared patent carbonate (Westmacott’s patent) is used in combination with chalk, grey, and all other limes. All the carbonic acid being removed from the lime in its burning, 75 per cent, of this acid is restored by its mixture with the prepared patent carbonate, and its induration immediately commences, instead of the lime gaining the carbonic acid by atmospheric influence through a lengthened period. It is used as a quick stucco for rapid plastering; and as a carbonated lime for external use it is in the course of a few days converted into a stone mortar.

Selenitic mortar is the name given to a composition lately invented by Major-General Scott. He was the first to observe, about eighteen years ago, that a limestone capable of conversion by burning into a hydraulic lime might furnish a good cement by simply allowing a small portion of sulphuric acid gas to pass into the kiln during the burning of the lime. Having found difficulty in carry ing out this process, he now mixes with the water used in the preparation of the mortar a small quantity of sulphate of lime (i.e., plaster of Paris, or gypsum) or green vitriol. It has the advantage, when used for plastering, of allowing the setting coat to be applied in forty-eight hours after the first coat has been put on. This mortar is said to save half the lime, is four times as strong, and sets in one quarter of the time required by common mortar. The lime will take six parts of sand, and is said to be an excellent substitute for Portland cement for concrete at less cost.

Asphalt, or mineral pitch (see Asphalt), has lately come into extensive use for paving, for covering the backs of arches, or rendering the walls of basements where wet is likely to soak through, also as a damp-course over the footings of walls to prevent the rise of damp, and for lining cisterns and tanks to prevent the escape of the fluid. The best qualities are the Vai de Travers and the Seyssel, both obtained from France. In using asphalt for paving, a bed of concrete, made of the best hydraulic lime, is first prepared, and made fair at top by a rendering of similar mortar. The asphalt will not dissolve with heat by itself, but will calcine in the caldron. A small quantity of pure mineral pitch is therefore first put in; when this is hot the asphalt is added, and soon dissolves; a quantity of powdered stone-dust is then stirred in, and a small portion of quicklime. The mixture in its melted state is then laid on the bed of concrete (which must be quite dry), and spread close and fair, some sand being sprinkled over the top and well trowelled in. The best proportions are said to be about 2 pints of mineral pitch to 10 K> of asphalt and one-fourth bushel of stone-dust. Another method of forming a paving is to place on the concrete a layer about 3 inches in thickness of hot asphalt in powder, and then to ram it down with hot iron rammers, until it has come to its proper consistency; it is then finished as usual. This has been lately much used for roadways in the city of London and elsewhere. The same material has been compressed into tiles about 6 inches square, and these laid on a good foundation. A very inferior imitation is made by mixing a quantity of sharp sand with gas-tar, heated in a caldron, and then adding some quicklime. This may do for rendering walls, &c., to keep out wet, but it is of very little use as paving. Gravel coated with tar, and theu laid and set in tar, rammed down, and sanded over, makes a very good pavement for ordinary footpaths.

As before noticed, particular attention must be paid to cleansing the sand to be used for mortar of every particle of clay or mud that may adhere to or be mixed up with it. Sea-sand is objectionable for two reasons: it cannot be perfectly freed from a saline taint, and the particles are moreover generally rounded by attrition, caused by the action of the sea, which makes it less efficient for mortar than if they retained their natural angular forms. Lime should not be slaked until the moment it is to be mixed up with the sand in mortar, but the sooner that is done after it is burnt the better. The proportion of lime to sand generally taken, and the best, is one to three; but if both the materials be of good quality, that is, if the lime slake freely, and become a fine pungent impalpable powder, perfectly clear from argillaceous or any other foreign matter, and the sand be clean and sharp, one part to four is enough; more is injurious. The ingredients should be well mixed together, and with just as much water as will suffice to make the compound consistent and paste-like. Of late years, in lieu of sand, burned clay, as above noticed, has been much used in localities where it is difficult to obtain the former material. This is ground up with lime in a mill, but unless very great care is taken in its manufacture the result is a very poor substitute for sand and lime mortar; and brick and lime rubbish have also been used in like manner, with an equally inferior result. Rain or other soft water should be used for the purpose of making mortar, and not spring or hard water, though any other may be preferred to what is brackish even in the slightest degree. Higgins recommended that lime-water should be used in preference to pure water. A quick-setting cement, such as those which are commonly used in building in England, and known as Parker’s or Roman cement, and Portland cement, can only be mixed or gauged as it is required for use. A bricklayer will keep a labourer fully employed in gauging cement for him alone. It is mixed with sand in the proportion of from about two or three to about five or six of sand, to one of the cement, according to the quality of the latter; and the labourer as he gauges on one board supplies the mixture to the bricklayer fit for use on another board, a spadeful at a time; it must then be applied within half a minute, or it sets and is spoiled and wasted, for it should never be worked up again.

The average size of bricks in England is a fraction under 9 inches long, 4∣ inches wide, and 2⅜ inches thick; and in consequence of this uniformity of size, a wall of this material is described as of so many bricks in thickness, or of the number of inches which result from multiplying 9 inches by any number of bricks; a 9-inch or one-brick wall; a 14-inch or one-brick-and-a-half wall (13⅛ inches would be more correct, in fact, for although a joint of mortar must occur in this thickness, yet the fraction under the given size of the brick is enough to form it); an 18-inch or two brick wall, and so on.

The great art in bricklaying is to preserve and maintain a bond, to have every course perfectly horizontal, both longitudinally and transversely, and perfectly plumb (which last, however, may not mean upright, though that is the general acceptation of the term, for the plumb-rule may be made to suit any required inclination, as inward against a bank, for instance, or in a tapering tower); and also to make the vertical joints recur perpendicularly over each other, which is vulgarly and technically called keeping the perpends. By bond in brickwork is intended that arrangement which shall make the bricks of every course cover the joints of those in the course below it, and so tend to make the whole mass or combination of bricks act as much together, or as dependently one upon another, as possible. The workmen should be strictly supervised as they proceed with it, for many of the failures which have occurred may be referred to their ignorance or carelessness in this particular. The object of bonding will be understood by reference to the diagram, fig. 1, Plate XX. Here, it is evident, from the arrangement of the bricks, that any weight placed on a would (supposing, as we are obliged to suppose, that every brick bears equally, throughout its whole length, a stress laid on every part of it) be carried down and borne alike in every course from b to c ; in the same manner the brick d is upbome by every brick in the line e f, and so throughout the structure. Eut this forms a longitudinal bond only, which cannot extend its influence beyond the width of the brick; and a wall of one brick and a half or two bricks thick, built in this manner, would, in effect, consist of three or four half-brick-thick walls, acting independently of each other, as shown in the plan at i in the diagram under fig, 1. If the bricks were turned so as to show their short sides or ends in front, instead of their long ones, certainly a compact wall of a whole brick in thickness would be produced; but the longitudinal bond would be shortened one-half, as at g c h, and a wall of any greater thickness, in the same manner, must be composed of so many independent one-brick walls, as at k in the plan before referred to. To obviate this, to produce a transverse, and yet preserve a true longitudinal bond, the bricks are laid in alternate courses of headers and stretchers, or of ends and sides, as shown in fig. 2, thus combining the advantages of the two modes of arrangement abc and g c h fig. 1, ina b c fig. 2. Each brick in fig. 2 showing its long side in front, or being a stretcher, will have another lying parallel to it, and on the same level, on the other side, to receive the other ends of the bricks showing as headers in front, which in their turn bind, by covering the joint between them, as shown in the end of such a wall at d. Thus a well-bonded 9-inch or one-brick wall is produced. The end elevations of the same wall at e and f show how the process of bonding is pursued in walls of one and a half and two bricks thick, the stretcher being abutted in the same course by a header,—thus, in a 14-inch wall, inverting the appearance on the opposite sides, as seen at e 1 and producing the same appearance in an 18-inch wall, as at f. In the diagram under fig. 2, at g, is the plan of a 14-inch wall, showing the headers on one side, and the stretchers on the other, and at h is the plan of the course immediately above it, in which the headers and stretchers are inverted; at k and i are shown in the same manner the plans of two courses of an 18-inch wall. This is called English bond. ’Thicker walls are constructed in the same manner by the extension of the same principle.

But a brick being exactly half its length in breadth, it is impossible, commencing from a vertical end or quoin, to make a bond with whole bricks, as the joints must of necessity fall one over the other. This difficulty is obviated by cutting a brick longitudinally into two equal parts, which are called half headers. One of these is placed next to a whole header, inward from the angle, and forms with it a tbree-quarter length between the stretchers above and below, thus making a regular overlap, which may then be preserved throughout; half headers so applied are technically termed closers, and are shown next the upright angle of the wall fig. 2, and the first joints inwards from the square ends by the headers in the plans at g and h. A three-quarter stretcher is obviously as available for this purpose as a half header, but the latter is preferred, because, by the use of it, uniformity of appearance is preserved, and whole bricks are retained on the returns. In walls of almost all thicknesses above 9 inches, to preserve the transverse, and yet not destroy the longitudinal bond, it is frequently necessary to use half bricks; but it becomes a question whether more is not lost in the general firmness and consistence of the wall by that necessity, than is gained in the uniformity of the bond. It may certainly be taken as a general rule, that a brick should never be cut if it can be worked in whole, for a new joint is thereby created in a construction, the difficulty of which consists in obviating the debility arising from the constant recurrence of joints. Great attention should be paid to this, especially in the quoins of buildings, in which half bricks most frequently occur; and there it is not only of consequence to have the greatest degree of consistence, but the quarter bricks used as closers are already admitted, and the weakness consequent on their admission would only be increased by the use of other bats, or fragments of bricks.

Another mode of bonding brickwork, which may be supposed to have arisen from the appearance of the ends of a wall according to the former mode of arrangement (see e and f, fig. 2), instead of placing the bricks in alternate courses of headers and stretchers, places headers and stretchers alternately in the same course, fig. 3. The plans below this at c and d are of two courses of a 14-inch wall, with their bond, showing in what manner the joints are broken in the wall horizontally as well as vertically on its face. This is called Flemish bond. Closers are also necessary to this variety of bond; half bricks also will occur in both, but what has been said with reference to the use of them in the former applies even with more force to the latter, for they are more frequent in Flemish than in English, and its transverse tie is thereby rendered less strong. Their occurrence is a disadvantage which every care should be taken to obviate. The arrangements of the joints, however, in Flemish Bond, presenting a neater appearance than that of English bond, it, is generally preferred for external walls when their outer faces are not to be covered with some composition; but English bond should have the preference when the greatest degree of strength and compactness is considered of the highest importance, because it affords, as we have already noticed, a better transverse tie than the other.

l Mr W. IIosking was the first to notice (in the last edition of this work) that what is in England called Flemish bond is unknown in Flanders, and is practised in the British Isles alone. In Flanders, Holland, and Rhenish Germany, which are bricklaying countries, no kind of bond is found but what is known in England as English bond. But it has lately been noticed that the mediaeval brick buildings in the north-east of Germany are worked in Flemish bond, or as it is there called “cross-bond;” and it is also to be seen at Brussels in work of about the end of the 18th century. Many of the buildings designed by Inigo Jones in England, and perhaps all of those by Sir C. Wren, are executed in Flemish bond, which name, it has been suggested, might have been derived from the word “flemishing” used by workmen, and thus applied to brickwork as meaning work better “finished off” than the other kind.

It has been attempted to improve the bond in thick walls by laying raking courses in the core between external stretching courses, and reversing the rake when the course recurs. This obviates whatever necessity may exist of using half bricks in the heading courses, but it leaves triangular interstices to be filled up with bats, as is shown in Plate XX. fig. 4. This represents the plan of 36-inch or three-brick wall with raking courses at α, between external ranges of stretchers, and lying on a complete course of headers, and at b a wall of the same thickness herringboned; courses of headers would bed and cover this also, and, in the second course above, the raking or herringboning would be repeated, but the direction of the bricks reversed. It will be seen that the latter demands, in addition to the triangular filling in bats at the outer ends of the diagonally placed bricks, half bricks to fill up the central line of interstices, rendering herring-boning more objectionable in that particular, though it has some advantages over simply raking, or thorough diagonal courses in other points. Neither mode should, however, be had recourse to for walls of a less thickness than three bricks, and that indeed is almost too thin to admit of any great advantage from it.

Not second in importance to bonding is, that the brickwork be perfectly plumb, or vertical, and that every course be perfectly horizontal, or level, both longitudinally and transversely. The lowest course in the footings of a brick wall should be laid with the strictest attention to this latter particular ; for the bricks being of equal thickness throughout, the slightest irregularity or incorrectness in that will be carried into the superimposing courses, and can only be rectified by using a greater or less quantity of mortar in one part or another, so that the wall will of course yield unequally to the superincumbent weight, as the work goes on, and perpetuate the infirmity. To save the trouble of keeping the plumb-rule and level constantly in his hands, and yet to insure correct work, the bricklayer, on clearing the footings of a wall, builds up six or eight courses at the external angles (Plate XX. fig. 5), which he carefully plumbs and levels across, and from one to the other. These form a gauge for the intervening parts of the courses, a line being tightly strained from one end to the other, resting on the upper and outer angles of the gauge bricks of the next course to be laid, as at a and b, and with this he makes his work range. If, however, the length be great, the line will of course sag; and it must therefore be carefully set and propped at sufficient intervals. Having carried up three or four courses to a level, with the guidance of tho line, the work should be proved with the level and plumbrule, and particularly with the latter at the quoins and reveals, as well as on the face. A smart tap with the end of the handle of the trowel will generally suffice to make a brick yield what little it may be out, while the work is so green, and not injure it. Good workmen, however, take a pride in showing how correctly their work will plumb without tapping. In work which is circular on the plan, both the level and the plumb-rule must be used, together with a gauge-mould or a ranging trammel, for every course, as it must be evident that the line cannot be applied to this in the manner just described. For every wall of more than one brick thick, two men should be employed at the same time, one outside and the other inside; one man cannot do justice from one side even to a 14-inch wall.

Bricks should not be merely laid; every brick should be rubbed and pressed down in such a manner as to force the mortar into the pores of the bricks, and so produce absolute adhesion. Moreover, to make brickwork as good and perfect as it may be, every brick should be made damp, or even wet, before it is laid, especially in hot weather, otherwise it immediately absorbs the moisture of the mortar, and, its surface being covered with dry dust, and its pores full of air, no adhesion can take place; but if the brick be damp, and the mortar moist, the dust is enveloped in the cementitious matter of the mortar, which also enters the pores of the brick, so that when the water evaporates their attachment is complete. To wet the bricks before they were carried to the scaffold would, by making them heavier, add materially to the labour of carrying; in dry weather they would, moreover, become dry again before they could be used, and for the bricklayer to wet every brick himself would be an unnecessary waste of his time; boys may therefore be advantageously employed to dip the bricks on the scaffold, and supply them in a damp state to the bricklayer’s hand. A watering-pot with a fine rose to it should also be used to moisten the upper surface of the last laid course of bricks preparatory to strewing the mortar over it. In bricklaying with quicksetting cements all this is of even more importance; indeed, unless the bricks to be set with cement are quite wet it will not attach itself to them at all.

As mortar is a more yielding material, used in brickwork merely for the purpose of making the detached portions of the staple adhere, by filling up their interstices and excluding the air, and the object is to produce as unyielding and consistent a mass as possible, no more should be used than is sufficient to produce the desired result. No two bricks should be allowed to touch, because of their inaptitude to adhere to each other; and no space between them should be left unoccupied by mortar which may produce adhesion. When the bricks are a fraction under 2⅜ inches thick, four courses of bricks and mortar, or brickwork, are usually allowed 11 inches in height; and if they are fully that thickness, four courses are allowed 11∣ inches. The result of thick beds of mortar between the bricks is, that the mortar is pressed out after the joint is drawn, on the outside, in front; and being made convex instead of slightly concave, the joints catch every drop of rain that may trickle down the face of the wall, and are thus saturated; the moisture freezes, and in thawing bursts the mortar, which crumbles away, and creates the necessity, which is constantly recurring, of pointing the joints to preserve the wall. The diagram, fig. 6, shows the section of a 9-inch wall, with the joints on the side a as drawn, and on the side b as bulged, in consequence of the quantity of mortar in them yielding to the weight above. This, too, is in addition to the inconvenient settling, which is the consequence of using too much mortar in the beds. In practice, bricklayers lay the mortar on the course last finished, and spread it over the surface with the trowel, considering that it will fill the space between the bricks of that course, in addition to what they may have placed in the edges of the outside joints; but the mortar ought not to be so thin as to fall into the joints by its own weight; so, unless they press it down, half the height of the space between the bricks remains unoccupied, and the wall is consequently hollow, incompact, and necessarily imperfect. To obviate this, it is common to have thick walls grouted in every third or fourth course; that is, mortar made liquid, and called grout, is poured on and spread over the surface of the bricks, that it may run in and fill up the joints completely. This, at the best, is but doing with grout what should be done with mortar; and filling or flushing up every course with mortar requires very little additional exertion, and is far preferable. It also assists in making the house warmer and drier, by preventing the passage of wind or damp through the joints.

All the walls of a building that are to sustain the same floors and the same roof should be carried on simultaneously; under no circumstances should more be done in one part than can be reached from the same scaffold, until all the walls are brought up to the same height, and the ends of the part first built should be racked back, as at a b, Plate XX. fig. 2, and not carried up vertically with merely the toothing necessary for the bond, as at a b, fig. 3.

Brickwork should never be carried on in frosty weather, nor even when it is likely that frost will occur before the walls can be covered in or become so dry as not to bo affected by frost. Covering an unfinished wall with a thick layer of straw when frost may supervene is a very useful precaution; and on the straw weather-boarding should be laid, to prevent access of moisture from rain or snow. Merely wet weather may be guarded against by following the directions given above as to flushing every course of the work well up with mortar, so that no interstices be left into which water may insinuate itself, and by covering the walls with boards to act as a coping when the men are not actually at work on them; the joints in the face of a wall that is not to be plastered in any way should be protected in this manner with great care.

After the footings of a wall (above noticed) have been brought up to the level of the finished surface of the ground, or to the underside of the joists of the lowest floor, there should always be introduced a damp-proof course, intended to prevent that rise of damp from the soil in the brickwork which is the cause of so much disfigurement and injury to buildings. This damp course is formed in various ways, as a layer of asphalt, or asphalt canvas, or some similar material. One of the best and most usual, as the materials are always at hand, is formed of two courses of slates, well breaking joint, and set in cement. Another is Taylor’s or Jennings’s patent stoneware damp course, which being pierced horizontally admits air to the space under the floor and thus ventilates it.

Where the ground would come against the walls of a basement story, it is requisite, in order to keep them dry, either to form an open drain or area, or to make what is called a dry area. This is done by building up against the soil a thin wall of brickwork not less than 8 inches from the main wall, and either straight or curved, and covering it over above the ground with stone or slate, as in fig. 7. Thus any water coming through the thinner wall falls down, and is conveyed away or soaks through the bottom. This thinner wall requires support from the main one, and the cavity has to be ventilated,

Besides the outer or main walls of a house, there are interior walls, or partitions as they are called. Thes n in large structures are always executed in brickwork; in smaller ones they are usually constructed of timber; and these timbers are often filled in between the uprights by brickwork formed of bricks laid fiat or on edge according to the thickness of it. A plate of wood is occasionally introduced to strengthen the work, which is then plastered over This is called a brick-nog partition. In many of the model lodging-houses in London the partition walls have been constructed a half brick in thickness in good mortar, for the whole height of the building, the floor joists being fixed against them to steady them.

Another sort of wall consists of two skins of brickwork with a few inches between them; this is called a hollow wall. The two skins, either both of half a brick thick, or the outer one of one brick and the inner one of half a brick, are tied together by iron band-ties at various intervals. These when straight are sometimes found to transmit the wet blown through the outer facing to the inner one, so a bend or loop is formed in the centre of the tie, which throws off the water. This hollow space tends to make the houses both dry and warm, but it is said to form receptacles for insects, <fcc. An addition to such walls has been lately made by a series of these looped ties supporting a course of slates placed not quite vertical but sloping back slightly. The next course of ties is built in at such a level that it fixes the top of this first course of slate in place, and provides a starting for the next course. Thus, in the heart of the wall there is a continuous surface of slates, slightly overlapping at joists and at beds, and so placed that whatever moisture blows through the outer skin is not able to penetrate, but will trickle down the slates to the bottom of the cavity in the hollow wall. This is one of the many building patents of Mr John Taylor.

A rod of brickwork will consume about 4500 bricks, though the number will be a few more or less than this, as the bricks happen to be below or above the average size, and as the joints are made thicker or thinner. The quantity of mortar, it is evident, will be affected by the latter consideration also; but in London it is generally reckoned at from ninety to a hundred striked bushels to the rod, or from four to four and a half cart-loads, each containing about one cubic yard. The labour on a rod of brickwork may be done on an average by a labourer in four days; this, however, does not include making and turning the mortar, nor scaffolding. Many things will, however, affect the time in which the work may be performed, both of the bricklayer and his labourer; the former can do or·.e-fourth as much more, at the least, in walls which are to be plastered, as in those in which he has to keep the perpends and draw the joints, &c., and more in thick walls than in thin ones; and the capability of the latter will depend, inversely, on the rate at which the former can proceed, on the distance he may have to carry the bricks and mortar to the foot of the ladder, and mainly on the height he has to carry the materials up the ladder. In great heights, however, the materials should be hoisted.

Tiling being much less in vogue than formerly, in consequence of the better appreciation of the superior qualities of slate for covering roofs, and the moderate cost at which slates are now furnished to the builder, it no longer maintains its separate artificer, but is performed, when it is required, by the bricklayer. Tiling is for the most part of two sorts—plain tiling and pantiling. Plain tiles are simple parallelograms, generally about 10⅛- inches in length, G inches wide, and ∣ 0 f an inch thick; and each tile has a hole pierced through it near one end, to receive the oak pin by which it is hooked to the lath. The tiles are laid in mortar and sometimes in hay, or moss, on the laths, which in England are of oak or fir, with an overlap of 6, 7, or 8 inches. The greatest overlap or smallest gauge makes the securest work, though it does not present so good an appearance externally as a longer gauge does; and it requires, moreover, a greater number of tiles and laths, thereby adding materially both to the weight and the cost. The great overlap and the mortar (or hay or moss) are both necessary to prevent the rain and snow from driving in between and under the tiles, especially when of a low pitch. Plain tiling requires the pitch of the roof to be at an angle of at least 50°, and is one of the heaviest coverings that can be used, though it is at the same time one of the warmest. The tiles, however, readily and rapidly absorb moisture, which they communicate to the laths and rafters under them, to the serious injury of both the latter; and the mortar in which they are set requires to be frequently pointed, the constant atmospheric changes to which it is exposed occasioning it to crumble and fall away in no long time. Terro-metallic tiles are made with projections at the back to catch on the laths, in lieu of pegs. Italian tiles have been made in England since about 1840, and are occasionally used. They are slightly curved, fit easily one into another, and have a horizontal indentation across the upper part to prevent the wind drifting the rain over the head of the tile. They have either wide or narrow vertical rolls. Taylor’s new roofing tiles have a plane surface with slightly turned up edges at the sides, and a lump on the surface near the upper edge to prevent the upper tile slipping. The cover tile is of a similar size and form. They are recommended as half the weight of the common tiling; they are about as light as slating, and may be laid to nearly as flat a pitch.

Pantiles are parallelograms of irregular surface, straight in the direction of their length, which is 13⅜ inches, but twisted in the transverse section. Measuring the whole surface across, a tile is 9 inches wide, but in a right line from point to point not more than 7, and its thickness is half an inch; a small tongue or lip is bent down at one end from its flatter convexity, on the under side, to hook it to the lath by, instead of a wooden pin through it, as in a plain tile. Pantiles are set dry or in mortar, on laths. They are not laid side by side, but overlap laterally as in 6g.

8; consequently all the overlap they have longitudinally is 3 or 4 inches only, or enough to prevent rain and snow from driving up under the upper, over the end of the lower tile; and hence pantiling is but little more than half the weight of plain tiling. It is, however, a much less warm covering for houses, and is more liable to be injured by violent gales or gusts of wind than the latter is; but again, it presents a far more pleasing appearance to the eye. Pantiling will not bear a much flatter pitch than the other. It is greatly improved by being pointed on the inside with lime and hair. Sometimes, indeed, the whole of the work is, as we have said, set in mortar; but this mode has disadvantages to which pointing internally is not liable, and its superiority in other respects is questionable. In both pan and plain tiling large concave tiles are used to cover the hips and ridges of a roof. These are not generally made to overlap each other in any situation, but are set in mortar, and fastened with nails and hooks fitted for the purpose, and driven into the woodwork of the roof. In addition to these an ornamental ridging or cresting is often introduced. A variety of patterns are now made for this purpose. Another form of pantile very useful for common purposes is the Bridgewater tile; it is rather wider than the common tile and has a double roll, being about 16∣ inches wide and 14 inches long.

As plain tiling is heavier than slating, the plates and rafters of the roofs have to be made stouter than is necessary for slates, consequently the expense of the roofing is added to, supposing that the same thickness of wall be sufficient. The tile also imbibes one-seventh part of its weight or about 5 oz. of water in ten minutes, and takes many days to dry again thoroughly, this necessarily tending to deteriorate the timbers.

When the top of a brick wall is not protected by a roof, it must be covered or coped in some manner, or it will soon be destroyed by the weather. Sometimes this is done by means of a course of bricks set across it on their edges in cement, and called a barge course, but it is a very imperfect covering, for water will trickle down the face of the wall on both sides, as the coping brick can be no longer than the thinnest wall is in thickness. Two double courses of plain tiles may be put side by side under the barge course, making a projection over each face of about 1⅜ inch, as shown in fig. 9. This is much better than the barge course alone; but still the covering receives no inclination outwards to throw the water off; the upper surfaces are all horizontal. The same objection exists to foot-paving tiles, which are also used as a coping; but none of these methods is available for any wall above 9 inches in thickness. Stone coping, therefore, which may be made of sufficient width, and be both weathered and throated, is much to be preferred. One of the greatest faults in the modern practice of building, both architecturally as a matter of taste, and practically as a matter of prudence, is, that these copings, and cornices which serve as such, do not project sufficiently to protect the wall from the weather. A massive and well-projected cornice on a wall serves as a roof or pent-house to it; and, besides imparting great beauty to the plainest structure, protects the wall from the premature decay of its upper part especially, and of the joints generally, if it be unplastered brickwork, which thereby calls for the frequent repetition of pointing. Effective and pleasing cornices and blocking-courses may be formed with uncut bricks alone; and these, set in cement, would, with judicious management, add materially both to the appearance and durability of brickwork, without the foreign aid of either the plasterer or the mason. Figs. 10 and 11 show two of the approved modes of forming plain copings in brickwork to garden and other walls.

From the injury which accrues to the joints of brickwork through bad management in its execution and imperfect protection when executed, arises the necessity, so frequent at tho present day, of pointing. Sometimes frost will have supervened before the surfaces of the joints in a wall are dry; consequently, the mortar bursts and peels away, and the whole then requires to be pointed. Preparatory to this operation the scaffold, if it has been struck, must be re-erected, the mortar raked out of the joints to a depth of about ⅜ of an inch, or deeper if the injury have reached further;—this can be done by a labourer;—a bricklayer then goes over the whole with a hard hair brush and water to cleanse and moisten the joints; and then, with mortar prepared for the purpose, he carefully fills them all up, and neatly draws them with his trowel. This mortar must be of the best quality; it is generally compounded with a certain proportion of forge or smith’s ashes, which gives it a blue tinge, and adds greatly to its power of resisting the action of the weather. Cement is sometimes used instead of this blue mortar. If peculiar neatness be required, every joint is marked with a narrow parallel ridge of a fine white putty, in the composition of which bone-lime forms a principal ingredient. The former is called flatjoint, and the latter tuck-pointing. If it be an old wall that requires pointing, a scaffold must be erected before it; and where the putlocks cannot be rested on window-sills and the like, half bricks are generally drawn from the wall to make rests for them, and restored again when the work is done. The former process is then gone through with a common wall; but if it require tuck-pointing, the whole surface is well washed, and then coloured to look like new brickwork, before the pointing is done. The gauged arches over the windows and doors are always coloured, and the joints drawn with peculiar neatness. If in the original building of the wall the perpends have not been preserved, that is, if the vertical joints have not been made to fall perpendicularly in the alternately recurring courses, the workman in pointing stops up the old joints, which are irregular, with putty of a brick colour, and forms false new ones in the proper places.

Arches in brickwork are plain, rough-cut, or gauged. Plain arches are built of uncut bricks, and the bricks being parallelopipeds, an arch built of them must be made out with mortar; that is, the difference between the outer and inner periphery of the arch requiring the parts of which an arch is made up to be wedge-formed, as in fig. 12, which the brick is not, the difference must be made in mortar, as in fig. 13, so that the inner or lower angles of bricks used for this purpose should all but touch. The mortar should be more consistent than that used in ordinary walling; and the centre on which an arch of this kind is set or built should not be struck or removed until the work is thoroughly hard, or rather all such arches should be set in cement which will harden immediately. In consequence of this inherent defect in uncut-brick arches, in extensive continuous works, such as sewers, tunnels, vaults, <fcc., it is advisable to make them in thin independent rings of half-brick or one-brick thick, as the case may be; that is, a 9-inch arch should be in two half-brick arches, as at σ, fig. 6, Plate XX., and an 18-inch arch in two one-bricks, as at δ, each arch in the latter case being bonded in itself as in a common 9-inch wall with headers and stretchers. It is evident that, by this mode of structure, a greater quantity of the solid material comes into the back or outer ring or arch than into the lower one; and if they had been bonded together into one arch, as at c, all that difference must have been made up with mortar. Moreover, whatever pressure comes on the outer ring is carried by it directly to the inner or lower, from whose joints, however, the mortar cannot escape or be pressed out, the inner angles of the bricks, by meeting, preventing it below, and the bricks of the upper arch, which conveys the pressure, are themselves opposed to the back of the same joints, so that its power of resistance is made equal to that of the bricks themselves, except at the ends; which, in such works as we have supposed, are remote, and may be protected by the use of cement in their joints, whilst mortar is used in the rest. Rough arches are those in which the bricks are roughly cut with an axe to a wedge form, and are used over openings, such as doors and windows, wheu the work is to be plastered on the outside, or in plain back fronts, outhouses, garden-walls, &c., when, however, they are neatly pointed with what is called a tuck or tucked joint. Semicircular and elliptical arches are generally made plain, or without cutting the bricks; but arches composed of a smaller segment of a circle (vulgarly and technically called scheme arches), if not gauged, are cut or axed. Very flat arches are distinguished by the term camber, from the French cambrer, to round like an arch. It is arches of this kind which are generally employed over windows and doors in external work, and they too are either cut or gauged. Gauged arches are composed of bricks which are cut and rubbed to gauges and moulds, so as to form perfectly fitting parts, as in masonry. Gauging is equally applicable to arches and to walling, as it means no more than the bringing every brick exactly to a certain form, by cutting and rubbing, or grinding it to a certain gauge or measure, so that it will exactly fit into its place, as in the finer works of masonry. Gauged brickwork is set in a putty instead of common mortar, but it is seldom used except for arches in the fronts of houses, &c., which are to be neatly finished. These are for the most part straight, and are generally from 11 to 12 inches in depth, or the height of four courses of brickwork. Their value as arches will be best understood by reference to the diagram, fig. 7, Plate XX., by which it appears that all the material between the soffit of the straight arch or head of the opening b c, and the dotted line b f c, is useless, the intrados or soffit of the really efficient part of the arch being at that dotted line itself. This is the arc of an angle of 60°,—its chord, the width of the opening, being the base of an equilateral triangle constructed on it, and the joints are the radii of a circle whose centre is at a. b d and c e, the continuations of the sides of the triangle or radii a b and a c, are technically termed the skew-back of the arch. Sometimes the arc is made under a more acute angle, in which case the skew-back is less, that is, the external angles c b d and b c e are less obtuse; a smaller unavailable portion of the arch is thus left between the arc and its chord, but that portion is less securely retained under the flatter segment, because the joints or radii diverge less, or are more nearly parallel. These gauged arches being, as they for the most part are, but a half brick in thickness, and not being tied by a bond to anything behind them—for, indeed, almost the whole, if not the whole, of their height is occupied behind by the reveal and the wooden lintel— require to be executed with great care and nicety. It is a common fault with workmen to rub the bricks thinner behind than before, to insure a very fine joint in front. This tends to make the work bow outwards; it should rather be inverted, if it be done at all, though the best work is that in which the bricks are gauged to exactly the same thickness throughout. The same fault occurs when a gauged arch is inserted in an old wall, on account of the difficulty of filling up with cement the space behind the bricks. Fig. 8, Plate XX. is a transverse section of fig. 7, and the gauged arch, lintel, &c., in it show the total disconnection of the gauged arch with any surrounding brickwork to which it might be bonded. The absurdity of constructing arches circular on plan, especially in a thin unbonded shell of bricks, is so clear as hardly to require notice.

It is generally held that nothing but its own components should be admitted into a brick wall, except what is absolutely necessary for its connection with the other parts of a building, such as wall-plates and wood-bricks (and that these should be avoided as much as possible), templets, lintels, &c. Wall-plates are applied to receive the ends of the joists, and distribute the weight of the floor to which they belong equably along the walls. If the joists tailed singly on the naked bricks, their thin edges would crush those immediately under them, and the rest of the brickwork would escape immediate pressure altogether. Wall-plates may be avoided by the use of framed floors, which are carried by a few large beams, under whose ends stout pieces of timber or stone, 2 or 3 feet in length, are placed. These supports are intended, like a wall-plate, to distribute the weight over a considerable part of the wall, and prevent the necessity of placing the beam on the naked friable bricks, and are called templates. As bond timbers and wood-plates are now interdicted by the Buildings Act in London, the joists have to be tenoned into trimming joists carried by brick, stone, or iron corbels. Lintels are used over square-headed windows and doors, instead of arches in brickwork. They are useful to preserve the square form and receive the joiner’s fittings, but they should always have discharging arches over them, and should not tail into the wall at either end more than a few inches, that the discharging arch be not wider than is absolutely necessary. Fig. 9, Plate XX., indicates the elevation of the inside of part of an external wall with a window in it, and shows the lintel over the opening with a discharging arch over it, and wood-bricks under its ends, on the jambs of the opening. Discharging arches should be turned over the ends of beams, and templets also, as in fig. 10. They may generally be quadrants of a circle or even flatter, and should be turned in two or more half bricks over doors and windows, and other wide openings, but over the ends of beams they need not be in more than one half brick. Wood-bricks are used to prevent the necessity of driving wedges into the joints of brickwork to nail the joiner’s work to. They are pieces of timber generally cut to the size and shape of a brick, or portion of one, and worked in as bricks in the inner face of a wall, where it is known the joiners have occasion for something of the kind. This is principally in the jambs of the windows and doors for their fittings, and along the walls, at proper heights, for the skirtings or wainscotting, as the case may be. The use of bond timbers in brick walls is objectionable because of their liability to shrink and swell, to decay, and to be set on fire; and in England the use of timber in walls has, since the extension of the manufacture of iron in these countries, been in a great degree superseded by that metal in the form known as hoop iron. Thin and narrow strips of this metal are laid in the bed joints of mortar, at intervals more or less frequent according to the nature and character of the work, with the best effect in respect of compactness and consequent strength. An improvement on the straight band has been introduced by Mr Tyerman, whereby a notch is made and the tongue bent down, which coming at each hollow of the bricks tends to afford a better hold on the mortar.

It will be generally found that a brick wall built with mortar and faced with ashlar has settled inward to a less or greater extent, as the work has been more or less carefully performed. Indeed, in the nature of things it cannot be otherwise, unless the brick backing be worked in some cement which sets and hardens at once; for the outer face is composed of a layer of unyielding material, with few and very thin joints, which p erhaps do not occupy a fiftieth part of its height, while the back is built up of an infinity of small parts, with fully one-eighth its height of joints, which are composed of material that must both yield to pressure and shrink in drying. Some part of the ill effect attendant on this is obviated by the bond-stones, which tail in or run through the wall, and tendito keep the discordant materials together; but still much of it remains. And besides this, the internal or cross walls, which have no stone in them, will either settle down and shrink away from the external walls, or drag them inward, as they happen to be well or ill bonded or tied. For these reasons, brickwork built in this manner with masonry should be executed with exceedingly well-tempered mortar, made with no more lime than is absolutely necessary to cement the particles of sand together, and the sand again to the bricks, worked as stiff as it can be, and laid in as thin courses as may be to answer the purpose required of it. Above all, work of this kind must not be hurried, but allowed time to dry and shrink as it goes on. In some-large edifices the brickwork is carried up and completed, and after a sufficient time has elapsed for the work to have settled, the ashlaring is carried up and worked in with the bond stones set in the brickwork for the purpose.

Discharging arches over vacuities having been disposed of incidentally, we have now only to speak of them under openings, in which situation their use is to distribute the superincumbent weight equally over the substructure, or along the foundation as the case may be. For this purpose the arch is inverted, as shown in fig. 4, Plate XXI.; and by means of it the weight brought down by the piers is carried along the footings, which are thus equally borne upon throughout their whole length. Arches of two half bricks are indicated here, that being sufficient for ordinary purposes, and to develop the principle; in large and heavy works, arches of three half bricks, and even greater may be judged necessary. Any arc between a quadrant and a semicircle may be used with advantage; but an arc of less than 45° cannot be recommended for the inverted discharging arch under piers. Arches require abutments whether they are-erect or inverted; this is often forgotten when inverted arches are used.

Not the least important part of the bricklayer’s art is the formation of chimney and other flues. Great tact is required in gathering-over properly above the fire-place, so as to conduct the smoke into the smaller flue, which itself requires to be built with, great care and precision, that it be not of various capacity in different parts, in one place contracted to a narrow straight, and in another more widely expanded, and so on. There is now often introduced at the level of the mantel, a plate with an opening in it through which the smoke ascends. This, which is called a chimney-hopper or chimney lintel, is very useful not only to ensure the proper gathering of the flue, as the brickwork of the flue is formed at once upon it, but as a substitute for the usual register, and it also renders needless the usual iron chimney bar required to support the breast. It is absolutely necessary that flues be of a certain magnitude, but the bore should be regulated by the size of the fireplace, or rather by the quantity of smoke to which it is required to give vent. For large kitchen fires it is considered best to have two flues.

Practical men differ as to whether a tapering flue, or an enlarging flue is best for carrying away smoke. They are usually made of one size throughout. Of late years cylindrical earthenware tubes have been used with advantage. and of a smaller bore than the common 9-inch by 14-inch capacity. With glazed tubes it has been found that the soot falls down with thunderclaps and other strong vibrations. Flues of brick are plastered or pargetted with a mortar in which „a certain proportion of cow-dung is mixed, which prevents it from cracking and peeling off with the heat to which it is exposed. The part brought out into the room from the wall, and over the opening, is called the breast. The flooring in the opening is called the hearth, fig. 8, Plate XXI.; it is set on the bricks or stones of the wall, and is usually of stone, although cement and iron plate are sometimes used. The slab is that part of the floor of a room which is immediately before the fire-place, and along the extent of its front. In basement rooms, this slab is supported by a brick wall brought up from the ground; but in upper rooms the slab is supported by a flat half brick arch called a brick trimmer, which is turned from the chimney breast under the hearth on one side to the trimmer joist on the other, which is generally made somewhat thicker than the other joists for this purpose. The chimney-piece which comes in front is fixed by the mason after the carpenter’s work is done.

The plate above mentioned assists in ensuring a proper draught to the flue, and preventing a smoky chimney. These are frequently caused by want of sufficient air to feed the fire, which must be supplied from the room itself or by a tube brought from the outside of the building. Another cause of smoke is too short a funnel, especially if the flue be a large one, as formerly built for sweeping by boys. Every fire-place must have its own flue. Other causes are—one fire overpowering the other, when there are two in one large room, or two rooms communicating by a doorway, or when the tops of chimneys are commanded by higher buildings, or by a hill, so that the wind sometimes blows almost perpendicularly into the tops of the chimneys that lie in its way and beats down the smoke. A down draught is usually produced by the difference of the external atmosphere from that in the room; this often brings down the smoke of a neighbouring chimney; it can occasionally be obviated by raising one of them, or by fixing on it one of the exhausting pots now manufactured for the purpose. The bad construction of fire-places is another cause of smoky chimneys, the throat being too large for the fire. We shall not attempt to describe the many patent and other inventions submitted for curing these nuisances, but what is known as Billings’s terminal must be excepted. It consists of a low conical top about a foot high, placed on the flue, and screened on each side by a terra-cotta baffler, rising somewhat higher than the pot; the wind striking the former is thrown upwards and assists in extracting the smoke; the latter prevents the smoke of one flue being blown down the adjoining ones in the same stack. The common terra-cotta pot with louvre sides is also useful and ornamental.

Brick and tile paving is performed by the bricklayer. Brick-paving is either flat or on edge, in sand or in mortar or cement. Brick flat-paving in sand, that is, with the bricks laid on their broadest surfaces, and bedded in and on dry sand, is very slight and fragile, and brick flat-paving set and bedded in mortar is very little better; for if the soil on which the paving is laid be light and sandy, the bricks are easily displaced by being pressed unequally; and if it be clayey it will probably be moist, and the thin porous brick absorbing the moisture, will generally become saturated, and present a damp unwholesome floor. Paving with bricks on their edges, however, forms a much better floor, and is preferable to a stone paving, if the latter be laid on the ground without the intervention of footings. Brick-on-edge paving in sand is generally used in beer cellars, pantries, dairies, stables, &c., as its numerous open joints allow wasted or discharged fluids readily to escape; and it is both cool and dry under ordinary circumstances. In mortar or cement, bricks on their edges form a sound, dry floor; the smallness of the surface exposed by each brick in this manner leaves them, of course, less susceptible of partial pressures, and the depth from the soil to the surface is such that damp rarely shows through. The paving brick differs from the common brick only in thickness, its dimension in that direction being rather less than 2 inches, instead of 2∣ inches, and in being rather harder and more compact.

Dutch clinkers are paving bricks, smaller and much harder than the English, and of a light yellow colour; they are 6 inches long, 3 inches wide, and 1⅜ inch thick, and are always set on edge and herring-boned, that is, instead of being placed in parallel lines, they are set at right angles to each other, as in fig. 14, yet with a perfectly even face. Paving tiles are made 9⅜ inches and 1l⅜ inches square, though they are called 10-inch and 12-inch or foot tiles respectively, the former being 1 inch, and the latter 1⅜ inch thick; they are set in courses, as stone paving would be, the alternating courses breaking joint. A sort of tiles called terro-metalĭic are manufactured for stabling and similar purposes.

Here may be mentioned the extended manufacture of ornamental tiles. The tiles formed in intaglio and enamelled, similar to those used by the Moors in Spain, have enabled the architect to break through the monotonous surface of brick buildings, and to introduce ornamental forms and colour without the necessity of resorting to plaster and stucco. From the geological position of London and many other towns, bricks must always be the prevailing material for building purposes; such means, therefore, for the safe introduction of colour and ornament are especially desirable and should be carefully studied. With this, too, has come the extended use of ornamental brickwork by the introduction of moulded bricks of all forms, and of many colours, together with a material of a like nature, by which decorative work of a more ornamental character can be obtained, namely terra-cotta, or prepared clay moulded or wrought and then burnt in a kiln. Tiles as above referred to are made for mosaic and tesselated pavements in plain colours (some being enamelled), for halls, footways of landings, conservatories, <fcc., also glazed tiles for hearths, and white and toned tiles, with the encaustic tiles of many colours, for walls. The former are manufactured of all sizes, so that by the combination of certain forms and colours an endless variety of patterns are obtainable. For pavements they require to be carefully set in cement on concrete, and in cement on walls.

Sewers and drains which are not cylindrical should be built with concave bottoms; this keeps the stream more together, and enables it the better to carry its impurities along with it, whereas a flat-bottomed drain offers a large surface for the particles of soil to attach themselves to, and the stream of water being more scattered is less efficient in force. Drains near houses, and in other places where it may be necessary to open them at any time, may be of the form of which a, fig. 1, Plate XXI. is a section, with a flat covering of stone paving, or large paving tiles, set and jointed with cement. Gun-barrel drains, of 9-inch or 12-inch diameter, as at b, are the best in exposed situations, because they are the strongest; but as there is no mode of cleaning, if they are too long to be raked, but by breaking them up, they should not be employed except, with a considerable fall and a frequent or constant stream of water through them, as from a pump trough, rain-water trunks, &c. They are constructed on a barrelled centre of wood, which tlιe bricklayer drags on as he advances with his work, finishing as ho goes. No drain should have an inclination or fall of less than one-quarter of an inch to a foot; and where the stream is infrequent and dull, as much more would bo a great advantage. Large sewers, which are accessible from the ends, or from side entrances, for men to clear or remove any accidental obstructions, are best made circular, elliptical, or egg-shaped, as in fig. 15. The last two shapes are gen ally preferred, because in proportion to the capacity the height is greater.

The form in fig. 15 maintains the greatest possible depth with a small quantity of fluid, and combines this qualification with those of great strength to resist external pressure and large capacity with a given amount of materials. The form shown at c, fig. 1, Plate XXL, is now disused, though it was long advocated for sound workmanship and regular joints. A rate of fall of 1 in 120, or 1 inch in 10 feet, is desirable, although less will suffice for a main sewer.

Pipes or hollow cylinders of well-made and well-burnt glazed stoneware form the most efficient house-drains. Such pipes are put together with great accuracy with sockets, so as to fit spigot and faucet fashion; movable tops are provided so as to give access to them at any part required, without taking up and relaying the drain from one or other of its ends, as was so often the case with the old brick drain, Proper bends, junctions, syphons, <fcc., are also made of the same material. In using pipes for drains, it should be borne in mind that a little larger than large enough is better than the reverse of this. No pipes should be laid down for a house-drain of less bore than 6 inches, nor should earthenware be used for drains requiring a greater bore than 12 inches; the material is too weak to allow of more, and the material is not strong enough to stand more than a dead pressure. Glazed stoneware pipes are also employed for small sewers in side streets, or to take off the collected soil and water from a short row of houses into the main brick sewer, and thence to a watercourse or to a reservoir of a main drainage scheme.

In building drains it is of great importance that proper traps should be constructed to prevent the ascent of foul air and the passage of vermin. At every sink there should be a bell-trap, and a well-trap within that, or near the hither end of the drain. Suppose a drain leading from a kitchen or scullery to the common drain of the house, in which it meets that which may come from the water-closet and other places. The bell-trap in the sink itself will prevent the return of smell when it is constantly in use, but it is liable to be left out, broken, or otherwise injured, or it may become dry by evaporation; it is, therefore, necessary to have a trap not so liable to such ordinary contingencies. Let a well be made 18 inches or 2 feet in diameter, square or round, and 2 feet 6 inches or 3 feet deep, across and below the level of the drain, as shown in plan, fig. 2, Plate XXL, and in longitudinal section, fig. 3; it must be built around with brick in cement, and be plastered on the inside with the same material, which will make it capable of retaining fluids. Uprightly across this well, and in the transverse direction of the drain, must be placed a sound piece of paving stone, so long that its ends may be inserted in the sides of the well, as shown in fig. 12, and so wide that its upper edge shall touch the covering of the drain, and that its lower may reach 6 or 9 inches down into the well below the bottom of the drain. Mortar or cement must prevent the passage of air between the upper edge of this trap-stone and the cover of the well and drain, and the trap is complete. The water coming from the sink flows along the drain from a to b (fig. 3), where it falls into the well, and filling it up to that level it flows on again from c in the direction of d, to the cess-pool or common sewer from which, however, no smell can return; for the trap-stone e, the lower half of which is thus immersed in water, completely bars the passage. It is evident, however, that if the well should leak the water in it may fall below the lower edge of the stone, and the efficiency of the trap be destroyed; but if it be made perfect in the first instance, there can be no danger of any inconvenience that a bucket of water thrown into the sink will not cure. It is from the drying up of the fluid in water-traps that uninhabited houses are so frequently offensive. These well-traps form an effectual bar to vermin, and they may, therefore, be advantageously placed at the entrance of water-closet drains, to prevent rats from getting at the soil-pipes, which they will gnaw and destroy if they can get access to them. Internal drains, or those which go through a house, should always pass under the doorways if possible, in external walls at least. If, however, circumstances should render it absolutely necessary that a drain be taken through a wall, an arched ring or bull’s eye should be made for it to pass by

All the traps to the drains should be ventilated, as well as the head of the drain itself, by a tube carried up to the top of the house, and away from any opening where the foul air could be blown into any of the rooms. The sewers should also be ventilated, if not by the gully or side gratings, then by a grating placed over them in the centre of the roadway There have been numerous suggestions for ventilating shafts in the lines of main drainage, but nothing beyond a tall lamp-post has been carried out, and no doubt this is sufficient.

In* country houses where the drainage is used for manure to the gardens or land, the drain from the closets may be led into a brick or iron tank or cesspool, the surplus water being carried off by an overflow drain. Cesspools are strongest if made cylindrical, and should be bricked round and domed at the top, with a manhole in it for access, which should be fitted with a stone, having a ring in it by which the stone can be raised. But whether they are made to retain fluids or not is not a matter of consequence, if they be placed in a secluded situation, where, if the object be not to get rid of the waste, there is seldom, at least, any desire to retain it. In towns and cities where the common sewering is as complete as it ought to be, and water-closets are used insteaα of privies, cesspools are unnecessary, as the soil becomes so much diluted by the water that goes down with it, that it flows readily enough through the private drains to the common sewer, and so on with the rest, to the common receptacle. Sometimes, indeed, it may be found necessary to clean out the well-traps before described, but this cannot often occur. Galvanized tanks are occasionally used in some parts of the country, with pumps attached, by which the sewage can be rendered available r the garden. Earth closets on Dr Moule’s system, or the cinder-sifting ash closets, are valuable for preventing the waste of an important manure. For workmen’s cottages in large towns and villages they must be of great service, but whether they are adapted to a town house, or are applicable on an extensive scale for the relief of town drainage, is a question which still remains unsolved.

The principal publications on Brickwork are as follows :—Moxon, Mechanick Exercises, 4to, 1682; Langley, London Prices of Bricklayers' Work, &c., 2d edition, 8vo, 1750; Saunders, Observations on Brick Bond, 8vo, 1805, and reprinted in vol. i. of the Civil Engineer and Architect's Journal, 1838; Elmes, Foundations, 8vo, 1808; Nicholson, Architectural Dictionary, 4to, 1819; Davy, Construction of Foundations, 8vo, 1839; Dempsey, Builder's Guide, 8vo, 1852. The foreign publications are mostly comprised in the list at the end of the Mason-work. For Ornamental Brickwork, see Degen, Constructions en Briques, 4to, no date; Essenwein, Norddeutschlands Backstein Bau im Mittelalter, folio, 1863; Runge, Essai sur les Constructions en Briques en Italie, folio, 1849 · Street, Brick and Marble Architecture in Italy, 8vo, 1855.

Mason-Work.

The word mason is derived directly from the French maçon, which signifies indifferently a bricklayer or mason. Du Cange attributes the origin of the word to the low Latin maceria, a wall; but a more probable derivation is that from the old German τneizan, to cut. Among ourselves, at present, we reckon three sorts of artificers— rubble or rag-stone masons, freestone masons, and marble masons. This last branch, however, is rather that of the carver or statuary. The art of working or reducing stone to the proper shape for the mason to set, i.e., to place them in the walls, <fcc., has generally been called stone-cutting, and depends very much on the nature of the stone for its details. Stone masonry is the art of building in stone.

The mason’s tools consist of a handsaw, for cutting soft stones; a drag, which is a flat piece of iron wherewith to finish its surface; chisels and gouges for forming mould ings, gauges and moulds for sinking them to the proper foims; a mallet, chisels, tools, and points for working the harder stones; a level, a plumb-rule, a square, a bevel, with rules of various sorts wherewith to try the surfaces in the progressive stages of the work. Granite is brought to a face by the scabbling hammer or granite axe, and the operation is called nidging. In rubbed work a surface is obtained by smoothing it with sand or gritstone. Marbles are polished by being rubbed with the gritston then with pumice-stone, and lastly with emery powder.

Rubble walls are scaffolded with single, and ashlar-fronted or other gauged stone walls with double-fronted scaffolding,—the former tailing one end of the putlocks in the wall, and the other having an inner row of standard poles, and ledgers parallel to the outer, making the scaffold entirely independent of the wall. In some places, however, it is the custom to dispense altogether with an external scaffold in building stone walls, particularly with gauged stones. With light and plain work this may be done without much inconvenience or retardation; but if the work be heavy or delicate, considerable delay and incorrectness result. Sometimes the finer work, such as that to mouldings, flutes, and foliate or other enrichments, is merely boasted or roughed out before the stones are set, and finished afterwards, but this can be done well only from a secure floor or scaffold on which the workman may feel he can move freely and surely. For large and elaborately decorated structures, such as a public building, a mechanical scaffolding has to be erected, by which some economy is effected through diminishing labour, or some emergencies met attendant on the works themselves. Where the face of a stone is worked in the shop and may have some weeks or months labour on it, it becomes a valuable work worth careful handling. Hence the old-fashioned kind of scaffolding, of poles and ropes, has been much superseded by the so-called whole timber or framed scaffold, with its tramway and crab engines aloft. It is usually formed by laying square timbers on the ground to receive similar uprights, which are secured by iron ties to it; on the heads of these are placed horizontal timbers, which are also secured to the uprights, and the whole is kept from changing position by timber struts and braces. On these another range may be erected, and so on to the required height. Tramways are placed on it, and a travelling crane, worked by hand labour or by steam, raises the neavy weights, carries them to their places, and at once deposits them in the work with great ease. By the use of a steam-lift, with a long arm to reach many feet above it, on the first stage of the frame scaffold, no other scaffold is necessary except a slight one for the use of the workmen to set the stone. The clock tower at the Houses of Parliament was built by a scaffold formed of two timbers, each 2 feet 3 inches deep and 14 inches wide, running across from side to side, on which rails were fixed to carry a travelling platform of the whole width which went the reverse way. To one side of the first named timbers was suspended a platform which carried the machinery for raising the materials from the bottom up the central shaft; they were then raised on to the traveller which carried them at once to the required spot for fixing. When a certain height of work had been done, the huge timbers were raised by six screw-jacks working together, and rested on the new wall, the jacks being removed and prepared for another raising when necessary. The Victoria Tower was erected on a somewhat similar principle, but having two travellers working upon a circular tramway on a strong trussed framing, the ends of each secured to a central drum. To raise the materials a strong under-trussed parallel framing was formed on one side, which brought them up on the outside of the tower.

Stones used in Building.— It may be useful to give a list of the stones principally used in building, according to their geological formation, with some practical remarks upon each.

Of igneous rocks of volcanic origin, the varieties which are used on the continent of Europe are those light stones called tufa and pumice, and the stone called peperino. The two former were extensively employed by the Romans in the filling in of vaulting, on account of their great lightness. The latter stone, which is obtained in large quantities near Rome, was used by that people extensively, particularly for substructures, being obtained in large blocks. Of the second division of igneous rocks, the trappean, porphyry and serpentine have been used, but chiefly as ornamental coloured stones, and have been generally classed as marbles. Of the third division, the supersilicated rocks, granite alone is now extensively employed, not only in engineering works, but in public buildings and dwellings. It is got from the quarries by splitting the blocks with wedges, and is so hard that it cannot be cut by any ordinary saws. It has to be worked first with large hammers, and then reduced by pointed chisels, and consequently is very expensive in building. Machinery is used very largely in cutting and also in polishing it. Some very good specimens come from Cornwall and Devonshire, but by far the best are from Dundee and Aberdeen. A variety of the latter, called Peterhead granite, is only to be equalled by the finest Oriental granites. The Kingstown granite from near Dublin is much used locally.

Of the aqueous rocks, mechanically formed, and of the arenaceous varieties, gravel is used for concrete, and sand in making mortar. Sandstones and gritstones are very extensively used. These are either laminated, as the York stone, used generally for paving, as it can readily be split into large surfaces of small relative thickness, or compact, as Old Red Sandstones, which stand very well internally, but perish sadly with the weather, as may be seen at Chester Cathedral. The New Sandstones, the best of which is the Calverley stone got near Tunbridge Wells, are easily quarried, but if sawn, the wet saw and sand must be used. The finer grained compact sandstones, which are comparatively free from iron, and form very good building-stones, are very numerous. Such are the Bramley Fall, used for bridge copings, plinths, &c.; the Park ≡, Eiland Edge, Whitby, and others, all in Yorkshire; the gton in Staffordshire; the Mansfield in Nottinghamshire; and the Minera quarries at Wrexham. A bed of the last is much used at Chester and Liverpool for building purposes, and it has just been introduced into the London market, for which city it is thought it will be very eligible, on account of its lasting qualities; it has been also used at the National Safe Deposit Company’s offices in London. Scotland can boast of some of the finest quarries of sandstone, the best, perhaps, being the Craigleith, much used at Edinburgh. The College, courts of law, Register House, Customhouse, Royal Exchange, National Monument, and many churches and private residences there, are built of this excellent material, which has also been extensively exported to Hamburg, Altona, Gothenburg, and other places. Humbie stone has also been much used, both at Edinburgh and at Glasgow, where it forms the Royal Exchange and Royal Bank; it is easier to work than Craigleith. Glamis is also a fine sandstone; the castle there, as well as those at Inver<juharity and Cortachy, and Lindertis House, are built of this material. In Fifeshire, at Cullalo, are quarries whence the stones τ° r i t 1 P onu ≡ n t to Lord Melville at Edinburgh, and that to Lord Nelson at Yarmouth, were obtained. In addition to beauty and durability, these stones have the merit of being capable of receiving the finest and smoothest forms from the chisel of the workman. Another class of sandstones are commonly called firestones, as they endure the action of fire better than most others. Of these the best known is the Reigate stone, which is the principal material used at Windsor Castle, Hampton Court, and in many old buildings round London. The Minera stone already mentioned is another.

Of mechanically-formed aqueous stones classed as argillaceous, the Clunch only is used in building. It may be seen in Ely and Peterborough cathedrals, and many other mediaeval buildings, and is a beautiful material for interior carved work, but will not stand the weather.

Of the aqueous stones classed as chemically formed, there is none of note but the Travertine, or, properly speaking, Tiburtine. This is a coarse grained stone, of warm colour, found in large blocks, and extensively used at Rome, both in ancient and modem buildings, of which the cathedral of St Peter’s may be cited as an instance, but it is unknown in England.

Of aqueous rocks, organically derived, the calcareous claim principal attention. The chief of these are the limestones, which are classed as compact, magnesian, or oolitic limestones. Of the first, the best, in the south of England, is that called Chilmark, of which Salisbury Cathedral and Wilton Abbey, and many other fine buildings, have been erected. In the Midland counties the Tottenhoβ stone, of which Dunstable Priory, Woburn Abbey, Luton church, &c., are built, is an excellent stone. There is also a stone of high quality got at Hopton Wood, near Worksworth in Derbyshire, used at Chatsworth, Belvoir, Drayton Manor, &c. Ancaster stone, near Sleaford in Lincolnshire, has been used for a number of years; also Ham Hill, near Yeovil, in Somersetshire. Of magnesian limestones we may name the Anston and Bolsover Moor stones, used formerly at Southwell Minster, and lately at the Houses of Parliament; the Tadcaster stones, used at York, Beverley, and Ripon Minsters, and very many other buildings; the Roche Abbey, used at the building of that name, and very many other churches in Y ork-shire and Lincolnshire; the Brodsworth, near Doncaster; and the Huddlestone, near Sherburne in Yorkshire. These stones contain a great deal of carbonate of magnesia, from which they take their name, are of beautiful texture, and stand well in the country as building stones, but fail in London.

A very excellent limestone for rough walling, especially for Gothic work, is that called Kentish Rag. 11 is found in large quantities in the neighbourhood of Maidstone; it is very hard, and is worked with large hammers instead of the saw. Jambs, strings, and mouldings are sometimes worked of it, but the hardness makes the work expensive; these, as well as the quoin stones and dressings, are therefore formed of Caen or Bath or other local stones. Kentish Rag does not answer for interior work.

The most important subdivision of the limestones used in masonry is the Oolitic. They are so called because they resemble, when broken, a conglomerate of globular eggs; they are also named roestones, from their resemblance to what is called the hard roe of a fish. Very good examples of these are the Barnack stone from Northamptonshire, of which Peterborough Cathedral, Croyland Abbey, Burleigh House, &c., are erected, and the Ketton stone, used at most of the colleges in Cambridge, and at Bury St Edmunds, Bedford, Stamford, Doulting in Somersetshire, and at Wells Cathedral and surrounding churches. But the principal English oolites used in masonry are the Bath and the Portland. The former, as its name imports, is found in the neighbourhood of Bath. The chief quarries are the Box Hill, Combe Down, Farleigh Down, and Corsham Down; all these quarries vary in quality at different depths. The Corsham Down is said to produce the finest in quality, and the Box Ground stone to be the hardest; but everything in the use of this stone depends on the bed selected. Large quantities of a similar stone are imported from Caen, in Normandy. This is more compact in texture than Bath, and therefore fitter for carving, but does not appear to stand our climate so well. The best variety of this stone is said to be the D·’Aubigny stone. Almost all these oolites can be sawn with a common dry saw, which saves a great deal in the labour of conversion. But, without doubt, the best of all this class of stones is that from the Island of Portland; for beauty of texture, and for durability, it perhaps exceeds any stone in the world. It seems the only one unaffected by the smoke of London; and therefore the greater number of its buildings, St Paul’s among the rest, are of this stone. Being of hard texture, however, it must be sawn by the use of sand and water, and is much more expensive to work than the softer oolites. There are between fifty and sixty quarries on the island. The best are said to be those on the north-eastern side; but, as with all stones, there is good and bad in every quarry, and everything depends on the selection. It is said that when Sir Christopher Wren built St Paul’s Cathedral, he had this stone quarried and exposed to the weather on the sea-beach for three years, before he suffered it to be used.

Of siliceous stones, flint is sometimes used for rough walling and for ornamental facing with brickwork; but in England this work is done by the bricklayer, and not the mason.

The only remaining class is that of the metamorphic rocks, of which the crystalline or saccharine and the serpentinous limestone are used; but these are all species of marbles, used more as ornamental than as constructive building-stones, and need not be dwelt upon here.

Many of the early buildings of the Middle Ages were entirely constructed of masses of concrete, often faced with a species of rough cast. The early masonry seems to have been for the most part worked with the axe and not with the chisel. A very excellent example of the contrast between the earlier and later Norman masonry may be seen in the choir of Canterbury Cathedral. In those times the groining was frequently filled in with a light tufa stone, said by some to have been brought from Italy, but more probably from the Rhine. The Normans imported a great quantity of stone from Caen, it being easily worked, and particularly fit for carving. The freestones of England were also much used; and in the first Pointed period, Purbeck and Bethersden marbles were employed for column shafts, &c. The methods of working and setting stone were much the same as at present, except that, as the roads were then in a very bad state, and in many places the only means of conveyance was by pack-horses, the stones were used in much smaller sizes. The methods of setting out work were, however, different from those of other styles, as might be expected from the difference of forms. As time went on the art of masonry advanced till, in England, in point of execution it at length rivalled that of any country.

From the regular and determined form of bricks, modes or systems for setting or arranging them, may be formed, and any workman, by habit and an exertion of memory merely, may become competent to build a brick wall as well as it can be built, but it is not so with stone used in common masonry walling. The workman in this material has for the most part to deal with masses of all forms and of all sizes, and a continual exercise of the judgment is required from him beyond the tact or skill which may be acquired by practice. For this reason workmen are generally less to be trusted to their own discretion in stone building than even in bricklaying. The young mason should be extremely careful to avoid making the beds of stones concave or hollow; for if this be done, in any case where the stones have to bear much pressure, they will flush or break off at the joints and disfigure the work. The best or highest sort of stone walling is the easiest to set; it is that in which the stones are all tooled and gauged in regular parallelogramic figures, to range in courses and suit the thickness of the wall to which they are to belong; and the most difficult to execute properly is that in which amorphous stones are used, the mason being allowed merely to dress them roughly with his hammer or axe, and fit them in as he best can to form the most compact mass: this is called rubble walling.

From the brittle nature of stone, great tact is required in setting, to prop or bear up the longer pieces in every part, or they will break across, and thus occasion more injury than could accrue if the whole mass had been made up of small pieces. Very long lengths, therefore, should be avoided, even in regular tooled courses, with which the bearing is or should be perfectly even, and a settling down of the work itself is hardly to be feared. There is a certain medium which may be preserved; and although the object is obviously, in stone as in brick walls, to form a compact mass, as unbroken into parts as possible, a mason will act judiciously in breaking a very long stone into two or more shorter ones, and working them in that state, though he thus makes two or more additional joints, well knowing that he has the power of counteracting to a certain extent the ill effect of joints made by himself, but that those made by accident are irremediable.

The observations made in the section on brickwork, on the use of mortar, will apply here also. Of whatever quality the stone may be of which a wall is to be built, it should consist as much of stone and as little of mortar as possible. If the stone be inferior in durability and power of resisting the action of the atmosphere to the mortar, besides the certain fact that the mortar will yield until it has set hard, and so far act injuriously, no ulterior good is .gained; and if the stone be the more durable material, the more of it that enters into the wall the better. Indeed, in rough walling, if the stones be pressed together until the more prominent angles on their faces come into actual contact, the interstices being occupied by mortar, it will be better than if a thick yielding mass were allowed to remain between them. Absolute contact, however, should not be permitted, any more than in brickwork, lest the shrinking of the mortar in drying leave the stones to such unequal bearing as the prominent parts alone would afford. Stone being generally of a less absorbent nature than brick, it is not a matter of so much importance that it be wetted before setting; nevertheless, adhesion on the part of the mortar is more certain and more complete, if the stones be worked in at least a damp state.

What bond is, and the necessity for it, have also been shown in the preceding section; and bond is of not less importance in stone walling than in bricklaying. We have also hinted above at the greater difficulty of understanding, forming, and preserving it in the former, and can now only add a few observations in addition that can be of any use, and these with reference to rubble walling particularly. Instead of carefully making the joints recur one over the other in alternate courses, as with bricks and gauged stones, the joints should as carefully be made to lock, so as to give the strength of two or three courses or layers between a joint in one course and one that may occur vertically over it in another. In bonding through a wall, or transversely, it is much better that many stones should reach two-thirds across alternately from the opposite sides than that there should be a few thorough stones, or stones extending the whole thickness of the wall. Indeed, one of the many faults of stone masons is that of making a wall consist of two scales or thin sides, with thorough stones now and then laid across to bind them together, the core being made up of mortar and small rubble merely. This is a mode of structure that should be carefully guarded against. There is no better test of a workman’s tact and judgment in rubble walling than the building of a dry wall, or wall without mortar, affords. Walls are frequently built with mortar that without it would have fallen down under their own weight in a height of 6 feet, in consequence of their defective construction,—thus rendering it evident that they are only held together by the tenacity of the mortar, which is very seldom an equivalent for a proper bond of stone. Masons are very apt to set thin broad stones on their narrow edges to show a good face, by which the wall is injured in two ways; the practice tends to the formation of a mere case on the surface of a wall, and it for the most part exposes the bed of the stone to the atmosphere, as a stone is more likely to be broad in the direction of its bed than across it.

The footings of stone walls ought to consist of the largest stones which can be conveniently procured. It is better to have them of a rectangular form than any other; and if they are not square, their largest surfaces should be laid horizontally. With this shape and disposition they will make the greatest resistance to sinking. WTιen footings can be obtained the full breadth of the wall in one piece, they are to be preferred; but if not, then every alternate stone in the course may be the whole breadth. Each course should be well bedded in mortar.

Rubble walling is either coursed or uncoursed. In the latter sort, fig. 5, Plate XXI., the work is carried on with stones of any sizes, as they occur, and without reference to their heights, somewhat in the manner of the Cyclopean walling of antiquity,—the interstices of the larger being filled up λvith smaller stones. For this work the mason uses no tool but the trowel to lay on the mortar, the scabling hammer to break off the most repulsive irregularities from the stones, and the plumb-rule to keep his work perpendicular. The line and level are equally unnecessary, as the work is independent of considerations which are affected by them. An attentive and intelligent workman will, however, make a sound wall with this specios of construction, by fitting the stones well together and packing them with as little mortar as possible, yet filling every crevice with it, and carefully bonding through to secure compactness, transversely at the least.

In coursed rubble walling, fig. G, Plate XXI.,the line and level are used, the work is laid in courses, each course being carefully brought up to the same level in itself, though no attention is paid to uniformity in the heights of the different courses. For this species of walling the stones are generally thoroughly dressed by the workman in the gross before he begins building. He is careful to get parallel beds to them, and he brings the best face of each stone to a tolerably even surface at right angles to the beds; the ends, too, receive some little attention, and for this purpose he uses an axe in addition to his scabling hammer. The quoins in coursed rubble walling are generally built with peculiar neatness and precision, and they are set to serve as gauge courses for the rest. This, when well executed, makes a sound and excellent wall. It presents, however, rather a rough and homely appearance, and in finer works must be covered with stucco or cement, or faced with ashlar.

Ashlar is an external rind of gauged stones in equal courses, having tooled or closely-fitting joints to give a wall a neat and uniform appearance; it is axed, tooled, or rubbed, as may be thought most in character with the structure, or that part of it to which it is to belong. Ashlar stones, or ashlars as they are commonly called, are made of various sizes on the surface, as the character of the edifice may require or convenience demand, and vary in thickness from 5 to 8 or 9 inches. Some of the ashlar stones must, it is clear, be used transversely as bond stones, or the facing, having nothing to connect it with the wall behind, would soon totter and fall. Bond stones are generally put in alternate courses, with the backing to the jambs of openings, such as windows, and offener, if these do not recur within a length of 5 or G feet; the bond stones themselves, too, should not fall in the same vertical chain, except when they are in the jambs of openings, but should break in their alternate courses. Ashlar is commonly set in fine mortar or in putty. It is generally recommended that ashlars should not be made regular parallelopipeds, but run back irregularly to tooth in with the backing, the vertical joints being left open from about an inch within the face of the wall, and the upper surface or bed of the stones made narrower than, though perfectly parallel to, the lower. These things may exert a slightly beneficial influence under some circumstances; but the mode of construction involved is so radically bad, that unless the backing is set in a quick-setting cement, or is so well packed as to be proof against its general tendency to settle away from the ashlar facing, no method of the kind can materially improve it. A well-compacted wall of coursed rubble, the courses being frequently made up of whole stones and faced with ashlar, may be made tolerably sound and trustworthy. Brick backing, with ashlar facing, cannot be considered as good, though it has the advantage of not requiring battening and lathing for inside plastering, as the stone-backed wall does. Uncoursed rubble with ashlar has all the disadvantages of both the preceding, with nothing to recommend it before either of them. A thin inner brick wall, like a hollow wall, is very often necessary, where it is anticipated that the rain will be beaten through the stone-work by the impetuosity of the wind. The settlement of these two kinds of work during the setting of the mortar is so different, that the walls often separate; or where this is prevented by bond stones, the walls bulge outwards and bear unequally on their base. These evils are best prevented by using as little mortar as possible in the interior parts of the wall, and not raising tho wall a great height at a time.

In order to give an uniform colour to a stone or ashlar wall, masons mix up pounded chippings of the stone they have used with some lime, salt, whiting, and size, and a little ochre, with which they colour the stone as they clean off the work. It is called badigeon, and is used also on plastered walls, where joints are sometimes drawn in colour to represent stone-work. Small defects in the stone are filled up with the same, or with shell-lac and the pounded stone.

There are many different sorts of walling or modes of structure arising from the nature of the materials furnished in various localities. That of most frequent occurrence, perhaps, is a manner in which either squared, broken, or rounded flints are used. These depend entirely on the care with which they are arranged, and on the mortar with which they are compacted, as also on a coursed chain, which is commonly introduced at short intervals of larger stones or of bricks, to act as a bond; the quoins, too, in this species of structure are generally constructed of dressed stones or of brick. Another sort of building is that of Pisé work, which from its economy as well as its general utility, has been much used in various countries. It consists of merely compressing earth in moulds or cases, whereby houses of two or three stories in height can be raised. Strong earths, with a mixture of small gravel, form the best material. The earth cannot be used when it is either too dry or too wet; when prepared it is put into the moulds and rammed down. The openings for the doors and windows must be left at the time of building the walls; and the openings have to be faced with wood for hanging the doors or for inserting the frames. The exterior decorations are best made of stone or brick; wood will not unite very well with the Pisé; the flues are also formed of brickwork. The exterior should be cemented or rough-casted, which should only be done when the wall is quite dry, oι the cement will be cast off by the damp. The walls require to be bonded at the angles by thin rough planks to each course of about 3 feet in height, and the interior walls to be likewise so tied to the main ones. Such work has lasted over a century and a half. It was extensively practised at Lyons and in the south of France during the last century. Several attempts have been made of late years to build concrete walls for houses, and with much success. The process is similar to that already described. One patentee has been enabled to produce a cheap material wherewith he has built every part of a house,—walls, floors, staircase, and a flat roof, and even the doors, the material being set in an iron frame, thus rendering the house perfectly incombustible. Several such “monolithic doors” have lately been put up in London in place of plate iron doors.

Whatever objections lie against bond timber in brickwork apply with equal force at least to the use of it in stone walls. Hoop-iron bond is not only available in all kinds of stone walling, including the highly-wrought close-jointed kind, but it is invaluable, as it may be used both longitudinally and transversely as it may in brickwork; whilst it compels the building mason to bring his work up to a true and fair bed as often as the bond is to be laid in it. Discharging arches, it must be evident, are as necessary in and to stone walls as to walls of brick, and they may be treated much in the same manner. See fig. 10, Plate XX., and fig. 4, Plate XXI.

When walls are not entirely of masonry, in the ordinary course of economic building, stone is frequently used for copings, cornices, string and blocking courses, sills, landings, pavings, curbs, steps, stairs, hearth-stones and slabs, and chimney-pieces; to these may be added quoins and architectural decorations, or dressings for windows, doors, &c., though both the former and latter are not unfrequently executed in plaster composition or cements. Quoin-stones are gauged and wrought blocks with parallel beds and vertical faces, placed on the angles of buildings in the Greek, Roman, and Italian styles, with the intention of adding to their beauty and strength, as in fig. 7, Plate XXI.; they are used in all kinds of walling, and are generally made to project before the face of that to which they are attached, mostly with a weathered angular joint, or with a rectangularly grooved or moulded one. The quoins are coursed with the rest of the wall if it be of stone, and are made to occupy the exact space of a limited number of courses of brick in a brick wall, or of flints where these are used. Copings in Italian work to cover walls, parapets, <fcc., are worked with a plain horizontal bed, two vertical faces, and an inclined or weathered back or upper surface,— either forming an acute angle with the outer and wider, and an obtuse angle with the inner and narrower face, to throw the water off, shown at a fig. 9, Plate XXI.; or sloping to both sides from the middle, as at δ; the latter is technically termed saddle-back coping. In both cases they are made to project over the wall or parapet on both sides; and in the projected part of the bed under the edge or edges towards which the inclination is given, a channel or groove, called a throat, is cut, to intercept the water in its inclination to run inwards to the wall. On gables or other inclined planes the coping is neither weathered nor throated, as the water is necessarily impelled along its course to the lower end, and not over the sides. It is a curious circumstance that the mediaeval designers rarely made their copings to project on the inside of a parapet, as shown in fig. 16, so that the exterior projection, which was returned up, was perhaps intended as much for effect as use. To protect the separate stones of a coping course from the danger of being displaced by high winds or other accidental causes, and to form a chain through its whole length, the stones are linked together by cramps of copper or iron let into their backs and ran with lead. These metals, however, especially the iron, for the most part act very injuriously, from their exceeding sensibility to atmospheric changes, and their greater or less tendency to oxidation; indeed, the stone invariably suffers more than the work benefits from the metal cramps. Tenons, dowels, joggles, or dovetails, of stone, of hard word, or of slate set in Portland cement, applied so as to be protected from the weather, are far better, and would answer every desirable purpose sufficiently. Lead dowels, when small, are occasionally used. The value of joggling and doweling to stone-work is well exemplified in the construction of Eddystone lighthouse. Cornices are but ramified copings, and are or may be subjected to the same general laws. Care must be taken, however, in arranging them, that their centre of gravity be not brought too far forward, in the anxiety to project them sufficiently, lest they act injuriously on the wall by pressing unequally, and their own seat be also endangered. String courses economically, in contradistinction to architecturally, are meant to protect a set-off in a wall, by projecting over its lower face in the manner of a coping, as in fig. 7, Plate XXI., at c; the beds are worked parallel, and the outer face vertical or at right angles to them, but so much of the upper surface is weathered or sloped off as protrudes from the upper part of the wall to carry the water off; and, for the reason above stated with regard to copings, the lower bed just within the outer face is throated. A stone string course, cramped or dovetailed in the bed, forms an excellent chain round a brick wall; but the part of it in the wall should be of the exact height of one, two, or more courses of brickwork. The woodcut, fig. 17, is a usual cornice or string course in the later period of mediaeval art in England. A blocking course is either a very thick string projecting over or flush with the face of the lower part of the wall to cover a set-off; or it is a range of stone over a crowning cornice to bring the centre of gravity more in on the wall than it otherwise would be; in the former case it is treated exactly as a string, excepting that, if it bo flush below, there is no occasion for a throat; in the latter it has a horizontal case bed, parallel vertical sides, and a weathered back or upper surface. Sills are weathered and throated like the parts of a string course, Plate XXI., fig. 7, αand ό; yet in mediaeval work they may be seen flush with the upright of the wall. They are laid across window openings as a base to the sash-frame; distinct sills in the same line may, indeed, be considered as an intercepted string course. In the ordinary practice of building, window sills are seldom set in brick walls until they are absolutely required to set the sash-frames on; or they are set but not bedded, except at the ends. The object of this is to prevent any settlement that may occur in the piers from breaking the sills across on the unyielding part of the wall under the windows. A necessity for this, however, can only arise from bad construction; for with a good bond in the brickwork, all would settle together, and the sills might be completely bedded across at once.

Landings are platforms of stone, either over an area before a door, at the head of a flight of stairs, or as the floor of a balcony. They are made four, five, six, or eight inches in thickness, according to their extent and bearing · if not one piece of stone they are of nicely jointed pieces joggled and plugged together, and are worked on the face and edges just as their situation may demand. They should also be very carefully pinned into the walls. Fig. 18 will show the danger, should they not be so, through the full length of their insertion. If the front edge be pinned up, as at A, but a vacancy be left, as at B, the point C will become the fulcrum of a lever, and the landing have a tendency to turn at that point, and to break at the edge C. Every step and landing should have 8 inches hold in a brick wall. All landings should be well joggled; the joint joggles made as at a, fig. 19, is called by workmen a he, and that at b a she joggle. An accident at the Polytechnic Institution in London arose, no doubt, from the ’ carelessness of the workmen, who put two landings together, in which two she-joggles were worked, as in fig. 20, and filled the open space with plaster. There happened to be a large fossil in the stone close to the wall in the landing b, which, having no support from the other landing«, gave way, and caused the destraction of the lower portion of the staircase upon which it fell.

Stone pavings are prepared and laid in various ways. Ordinary paving is of self-faced or of tooled York; and for better purposes it is of rubbed Portland stone. For entrance halls, square stones, with the angles slightly cut off, the four spaces thus obtained being filled up by a small square of black or other coloured stone, makes a neat paving, which is replaced by marbles in best houses and public buildings, if a tesselated pavement be not required. Stone paving that is not exposed to the sun and air, if next the ground, should be laid on footings of brick or stone, or it will be constantly damp should the soil be close and clayey; but in yards, open areas, &c., it may be laid on the ground, bedded in sand, and jointed with mortar or cement. Stone-paved floors should be formed on brick arches, or on a timber floor prepared for the purpose; the latter, however, is a very bad mode of supporting paving, as the impression derived from the presence of the stone is, that the floor is incombustible; but if it be bedded on combustible material, the danger to human life in the event of fire is greater than if the stone paving did not exist at all. It is worked, cut, and set more or less expensively, according to circumstances. A curb is a range or course of thicker and stronger stone to bound a pavement, and is either flush with the paving showing as a step on its outer edge, or is raised above it to receive a balustrade, and shows on the outer side as a blocking course; in the latter situation it is generally joggled and plugged in the joints. The term step or steps alone is usually understood to mean external steps, whether arranged in long or short flights, or the single step in a doorway into which the door-frame is tenoned. A step should have a plain horizontal bed, and a very slightly weathered tread or upper surface,—the front or riser worked plain and vertical, or with a moulded nosing, and the back sunk with a joggle or bird’s-mouth joint to receive the step or landing above or behind it. Steps for areas or back courts are often made of 2 or 2∣ in. stone for the tread, the riser being formed of a 4∣ or 5 in. stone, both tailed into a wall at one or both ends. This is much lighter in effect. Slate is sometimes used for the treads.

Stairs are but a flight or combination of steps used internally, and the general principle of designing staircases, as regards the rise and tread of steps, setting out curves, curtails, landings, &c., are given in the part treating of joinery. The chief difference between these and other staircases consists in the fixing, the one being framed with wooden strings, while the other have no strings, but are supported entirely by the walls. If there be a wall at each end, they are simply built in at the time the work goes up; but if they are supported at one end only, they are called geometrical stairs, and depend entirely on their being securely wedged into the wall; on which and on the support each derives at one edge from the step below, they wholly rely. If they are square in section, they are called solid steps; but as the under side or soffit, then, is irregular, it is usual to make the steps of somewhat a triangular shape, so as to present a continued soffit. In this case they are called arris, or feather-edge steps. Care should be taken that there are no sudden or irregular changes in the curves. These may be easily avoided by the method shown in the portion relating to joinery for the easing of the curves and ramps in handrails.

In houses built of stone the flues are usually formed in brickwork. The chimney-pieces consist of plain jambs, or boxings, or other vertical sides more or less decorated and moulded, and of the architrave or transverse covering or mantel, fig. 8, Plate XXI., with its shelf or cornice. The parts of a chimney-piece are generally put together with an adhesive plaster or cement, and affixed to the yvall or chimney-breast behind with cramps, holdfasts, and plugs. The material of which chimney-pieces, if not of wood, are composed, varies from the coarsest stone to the finest marble; and the labour on them varies to a still greater extent.

Masonry to receive architectural decorations is generally worked into the walls as they are carried up; but as they are seldom homogeneous either in matter or construction, the result is mostly the converse of what it purports to be, for the work is more frequently weakened than strengthened by the decorative masonry. Stones of which columns are to be composed, whether each column is to be of one stone or more, are generally roughly boasted out before they are set, and are finished afterwards to traversing moulds and templets with a plumb-rule, whose sides are cut to the diminution obtained from the bottom and upper diameters, whatever it may be. Flutes are cut at the same time and in the same manner. The beds of the joints in columns should be worked with the greatest precision, so as to obtain parallel planes, that they may fit firmly and closely together; they must not, however, be worked hollow to make a close joint externally, or the arrises will chip off. It is considered a good plan, where the columns are large, to put a piece of thin milled lead between the beds, cut circular, and extending to within a short distance of the surface, and that the rest be filled with a fine adhesive putty, made as nearly of the colour of the stone as possible. This makes a solid bed, and protects the arrises effectually; but it will not do so well for slight columns, because it narrows the bed so materially. A joggle or dowel of hard wood, slate, or cast-iron let into the core might be a sufficient counteraction, and it would certainly add to the stability of a polylithic shaft. The other parts of a columnar composition may be sufficiently cramped and joggled together with wood and metals, according to the situation, though it may be again remarked, that neither wood nor metal should be used, unless it can be protected from access even of the atmosphere.

Sections for Roman mouldings are given in the part relating to joinery, but as those used in Grecian architecture are parts of conic sections, and not struck by compasses, we give a short problem by which they may all easily be set out. Both Roman and Grecian mouldings are shown on Plate XIII. of vol. ii.

Let an ovolo be the moulding required (fig. 21), the height of which (to the point where the moulding curves backward) is AC or BD, and the greatest projection AB or CD; and let CE be a tangent line, or line which the curve must touch but not cut. Produce CA to F, and make A F equal to AC, and AG to ED. Divide GB BE each into the same number of equal parts as 5. Draw the co-ordinates from F and C to the respective · numbers, their intersections will trace the curve. If BE be more than half the whole height, the curve is an ellipse; if exactly half the height, itis aparabola; and if BE be less than half BD, the curve will be a hyperbola. All other mouldings can be drawn by this method, it being remembered that cymas, ogees, and all reflex curves, must be divided and drawn in two separate portions.

The mouldings in mediaeval architecture differ entirely from those of other styles. They are chiefly formed by a combination of curves stopped by right lines or worked into other curves and hollows. The mouldings differ in each of the several periods of the style in England, and also in the variations of the style as practised here and in each country on the Continent. We insert an outline, fig. 22, of a window jamb at Sleaford church, Lincolnshire, to show the forms and combination of an example during the Decorated period. A full description of those used in each style woμld exceed our limits, nor, indeed, is it a subject within the scope of this article. They are sometimes set out with the compasses, and many often appear to have been drawn by eye. We must refer our readers to the works of Professor Willis, F. A. Paley, and of J. H. Parker, for any details required about them. A very curious treatise was published by Professor Willis, called the Architectural Nomenclature of the Middle Ages, which goes at great length into the subject. A bead or astragal seems to have been called a bowtelle; a torus, a grete bowtelle; a hollow or scotia, a casement; an ogee, a ressaunte, and so on.

The methods of forking mouldings in the stones at the builder’s command have been already noticed at the commencement of this section. The soft stones and marbles are easily shaped into mouldings with the chisel and the mallet, and are sawn and the surfaces even finished with a plate having a fine edge. These stones will take mouldings of minuter character than the harder stones, which have to be worked with force, and require pointed tools to form the faces. The hardest material, granite, again, has to be stunned with heavy picks to make an impression, so that only bold ornaments have a good effect; much money has been thrown away in details more suitable for softer materials. Good effect is obtained by the contrast of axed and polished surfaces. A designer should visit the places where buildings in granite have been erected for a knowledge of a proper application of that material.

The earliest arches were circular and, of course, easily set out. But as the Pointed styles came in, several methods were used for describing them. Pointed arches may be classed as—1st, lancet; 2d, equilateral; 3d, depressed; and 4th, four-centred or Tudor. In the first the centres, as 1, 2, in fig. 23, are outside the arch a b. At Westminster Abbey the arches of the choir are so acutely pointed that the distances la and 2δ are nearly two-thirds of the entire opening a b. In the nave at York the points are without the arch at a distance of about one-fifth the opening a b. In equilateral arches the centres are exactly on the points a b in fig. 24, so that the apex c, joined to a and b, will form an equilateral triangle. The nave arches at Wells are of this description, and also those at Lincoln (see vol. ii. Plate XVIII. fig. 1). In later times the arches were of lower pitch, as fig. 25, and then, of course, the centres 1 and 2 were within the arch a b. At Salisbury Cathedral the distance al is one-sixth of a b, while in the choir at Lincoln (vol. ii., Plate XVIII., fig. 2) it is as much as two-fifths. To describe arches which shall be similar to one another throughout a building, however the openings may differ, this principle must always be borne in mind, that the centres are to be always distant from the points a b by some aliquot portion of the whole opening. This is the more important, as the lines of tracery will not fall into their proper places except the arches are set out upon some regular principle. If the arches are not equilateral, some distance from each point a b should be first determined on (say one-third the opening a &), and after this, whatever the span of the other arches may be, one-third its own opening is to be taken from the points a b, as the centres from which to strike its curves. The only exception is that, in mediaeval buildings, the arches to the doorways are frequently somewhat flatter than those of the windows. In the Tudor period the arches are very frequently drawn from four centres instead of two. As there has been great misapprehension as to four-centred arches, some persons treating them as parts of conic sections, whereas they are really parts of segments of circles, it is thought well to give two methods of describing these arches.:

First, when the width AB, fig. 26, of the arch, and the apex height OC, are given, and a tangent to the upper circle as CD. In this case draw AD perpendicular to AB, and set out Al equal to AD; draw C3 perpendicular to CD, and make CE equal to AD or Al; join IE and bisect the same as shown by a perpendicular meeting CE produced in 3; join 3 1 and produce towards F, then 1 and

3 will be the centres for half the arch; and, transferring the points across, 2 and 4 will be the centres for the other half. In the second case, when the width AB and the height OC, and the centres of the small circles 1, 2, are given. Make AD equal to Al, join CD (which will be a tangent to the upper curve), draw C3 at right angles thereto, make CE equal to Al, join IE, bisect the same, and proceed as before. The points FG, as has before been explained, arc the points where the circles will meet each other. The joints to these arches will all radiate to their respective centres.

Specimens of various sorts of the tracery which adorn the windows of the mediaeval periods, and are in fact their greatest glory, are shown in Plates XVIII., XIX., and XX. of vol. ii. The designs for tracery are almost infinite, and the various methods of setting them out would fill a volume. But although they display such ingenuity and fancy that one would think the design to be quite arbitrary, it will be found that they are all, or very nearly all, set out on the principle of geometrical intersections. An example will show the principles on which the mediaeval architects proceeded to describe the tracery, and also the method of finding the joints of the various pieces of stone.

Let a b (fig. 27) be the opening of the arch; as there are to be two mullions, divide the same into three equal parts, as a c, c d, d b; then determine the points from which to strike the arch. In this instance, for the sake of simplicity, we make it equilateral (as in fig. 24); a and b then are the centres for striking the main arch a eg, bfg, and the height og is that of an equilateral triangle. Produce the springing line, and the same opening of the compasses through c and d will give the principal inner branches of the tracery ce, df. From the centre o, with an opening extending to the middle of the lights a e, d b, strike a semicircle; raise perpendiculars from d and c to 1 and 2; draw a line through 1 and 2; on this and the springing line will be found the centres of the lower ogees; bisect the part of g o cut off by 1 2 in h, which is in fact the same thing as dividing the whole height o g into three; divide h g into three parts, at 3 and 4; through 3 draw a horizontal line, and set off from 3 distances one-third of the width o d, or draw the perpendicular lines as shown, which is better; then 5 and 6 will be the centres of the upper quatre-foil. From the line 1 2, on the same perpendicular as last, set down similar points, as at 7. These will be the centres for the lower subdivision as shown. Next draw ehf and subdivide by similar perpendiculars, and where the lines intersect, as at 8, will be the centres for the upper subdivisions. The lines thus drawn will form a species of skeleton diagram, as shown on the right side of fig. 27, which is called the element of the tracery, and is in fact the centre line of the mullion, as shown by a, fig. 28. On each side of this, using always the same centres for the same branches, draw lines, showing the face (or what the workmen call the nose) of the mullion, and answering to be; and then others answering to the sides of the mullion, as d e. Any other mouldings upon their sides or faces maybe drawn in like manner. Put in the cusping as shown, and the tracery is complete. The practical stone-mason will take care never to make a joint where there is an angle of any sort, as the point of a cusp. In all cases the joints must tend to the centres of the circles from which they are struck, and where the lines branch off in two directions, the joints must not be in one line, but must tend in two, or as many directions as there are branches, and each to the centre of such respective branch. When the lines are perpendicular, as at c and d, and at the joint below h, the joints are horizontal. A close inspection of fig. 27, where they are carefully drawn, will fully elucidate the matter. The elaborate west window at York Cathedral (see Plate XVI1I. of vol ii.) is entirely set out on this principle; and so is the still more remarkable instance, the eastern window at Carlisle, which is composed of 86 pieces of stone, and the design for which is drawn from 263 centres.

All the upper construction of windows and doors, and of aisle arches, should be protected from superincumbent pressure by strong relieving arches above the labels, as shown by the dark tints in fig. 27, which should be worked in with the ordinary masonry of the walls, and so set that the weight above should not press on the fair work, in which case the joints of the tracery, &c., will sometimes flush or break out.

In mediaeval vaults the crowns ab, cd, are not level, but all have a slight curve or spring, as shown in fig. 29, and the filling-in between them also is slightly curved, so as to partake in some degree of the character of the dome as well as of the groined arch; and for the most part the ribs in early vaulting are not true segments of ellipses, but approximations drawn by the compasses. The triumph of mediaeval stone-masonry, however, is that species of groin known as fan-vaulting. It is unlike that of any other age or time. The roofs of King’s College Chapel at Cambridge and of Henry VII.’s Chapel at Westminster are eminent and late examples. The earliest are supposed to be in the cloisters of Gloucester Cathedral. It is impossible in our limited space to give demonstrations of them, and we must refer our readers to the admirable treatise on the subject by Professor Willis, published in the first volume of the Transactions of the Royal Institute of British Architects. The filling-in between the ribs of mediaeval groins is generally of clunch, or of some soft stone, over which a layer of concrete is sometimes placed in such manner as to bind all together and to resist the thrust.

The bold and beautiful termination to mediaeval towers, which we call a spire, and the French cah flèche, is another proof of the skill of the mediaeval masons. These are generally octagonal, and rise partly from the wall of the tower and partly from arches thrown angle-wise from wall to wall inside, to cut off the corners, as it were, and afford a springing to the spire. The wonder of these constructions is their extreme lightness and thinness. The top of the spire at Salisbury is 411 feet from the ground, of which the tower takes up 207 feet, leaving, of course, 204 feet for the height of the spire itself; this is only 9 inches thick at the bottom, diminishing to 7 inches, or on an average only about the 300th part of its height. It has been attempted to show mathematically that the joints of a spire would be stronger if formed at right angles to its face; but they would then slope inwards and hold the wet, which in sudden frosts would do most serious injury; practically, therefore, it is found best to lay the courses on a level bed. They should, however, be frequently doweled and cramped together, but not with metal, for the extreme thinness of the stone would soon cause it to rust and break out the stone.

The principal publications on masonry are as follows :—

English.— Moxon, Mcchanick Exercises, 4to, 1677-93, 1700; Batty Langley, Ancient Masonry, fol., 1736; Nicholson, Practical Builder, 4to, 1823, &c.; Practical Treatise on Masonry, 8vo, 1828; Guide to Railway Masonry, 8vo, 1839-46; and Practical Masonry, Bricklaying, &c., 4 to, 1830; Dobson, Rudimentary Treatise on Masonry, 1849, 1856; Robson, Masons', Bricklayers', and Decorators' Guide, 4to, 1862.

Foreign.— De l’Orme, Nouvelles inventions pour bien bastir, &c., fol., 1561; Jousse de laFlèche, Secrets d’Architecture, fol., 1642; Bosse, La Pratiqué du trait pour la Coupe des Pierres, fol., 1643; Derrand, Des Traitset Coupe des Foutes, fol., 1643; De la Rue, Traité de la Coupe des Pierres, fol., 1728; Frézier, Traité de Stéréotomie, 4to, 1737; and Eléments de Stéréotomie, 1759; Simonin et Delagardette, Traité de la Coupe des Pierres, 4to, 1792; Douliot, Traité speciale du Coupe des Pierres, 4to, 1825; Vorlegeblätter für Maurer, fol., 1835; Adhémar, Traité de la Coupe des Pierres, fol., 1836-40; Normand, Épures d ’ Escaliers en Pierre, 4to, 1838; Le Roy, Traité de Géométrie descriptive, 4to, 1850; Claudel et Laroque, Maçonnerie Pratique, 8vo, no date; the article Maçonnerie in the various Encyclopédies; and the general treatise by Rondelet, L'Art de bien bâtir, with supplement by Blouet, fol., 1842-46.

Saw yer-work.

The labour of the sawyer is applied to the division of large pieces of timber or logs into forms and sizes to suit the purposes of the carpenter and joiner. His working-place is called a saw-pit, and his almost only important tool a pit-saw. A cross-cut saw, axes, dogs, files, compasses, lines, lamp-black, black-lead, chalk, and a rule, are all accessories which may be considered necessary to him.

The facility with which sawing whole timber is now done by the aid of the upright saw-frame, and smaller timber by the circular-saw bench, has in large factories and workshops caused the saw-pits to be out of date; timber after it has been cut at the mills can be again reduced into sizes and scantlings at a rapid rate, and with great exactitude and little labour. In some country parts, however, the saw-pit is still used. Unlike most other artificers, the sawyer can do absolutely nothing alone; sawyers are therefore always in pairs,—one of the two standing on the work, and the other in the pit under it. The log or baulk of timber being carefully and firmly fixed on the pit, and lined for the cuts which are to be made in it, the top-man standing on it, and the pit-man below or off from its end, a cut is commenced, the former holding the saw with his two hands by the handle above, and the other in the same manner by the box handle below. The attention of the top-man is directed to keeping the saw in the direction of and out of winding with the line tobe cut upon, and that of the pit-man to cut down in a truly vertical line. The saw being correctly entered, very little more is required than steadiness of hand and eye in keeping it correctly on throughout the whole length. In the operations of the carpenter and joiner much depends on the manner in which the sawyers have performed their part. The best work on the part of the carpenter cannot retrieve the radical defects in his materials from bad sawing; and although the joiner need not allow his work to suffer, bad sawing causes him great loss of wood and immense additional and otherwise unnecessary labour. Planks or boards, and scantlings, on coming from the sawpit, should be as straight and true in every particular, except mere smoothness of surface, as if they had been tried upon the joiner’s bench; and good workmen actually produce them so. Saw-mills, too, by the truth and beauty with which they operate, show the sawyer what may be effected; for though he can hardly hope to equal their effect, he may seek to approach it.

Carpentry.

Carpentry or carpenter’s work has been divided into three principal heads, namely, descriptive, constructive, and mechanical. The first shows the lines or methods for forming every species of work by the rules of geometry; the second comprises the practice of reducing the timber into particular forms, and joining the forms so produced so as to make a complete whole according to the intention or design; and the third displays the relative strength of the timbers and the strains to which they are subjected by their disposition. Here, we have merely to describe the practical details of carpenters’ work in the operations of building. The carpenter works in wood, which he receives from the sawyer in beams, scantlings, and planks or boards, which he cuts and combines into bond-timbers, wall-plates, floors, and roofs. He is distinguished from the joiner by his operations being directed to the mere carcass of a building —to things which have reference to structure only. Almost everything the carpenter does in and to an edifice is absolutely necessary to its stability and efficiency, whereas the joiner does not begin his operations until the carcass is complete; and every article of joiners’ work might at any time be removed from a building without undermining it or affecting its most important qualities. Certainly, in the practice of building, a few things do occur regarding which it is difficult to determine to whose immediate province they belong; but the distinction is sufficiently broad for general purposes. The carpenter, with the bricklayer or mason and some of the minor artificers, constructs the frame or hull; and the joiner, with the plasterer and others, decorates and rigs the vessel. On the former the actual existence of the ship depends, and on the latter depends her fitness for use.

The carpenter frames or combines separate pieces of timber by scarfing, notching, cogging, tenoning, pinning, and wedging. The tools he uses are the rule, the axe, the adze, the saw, the mallet, hammers, chisels, gouges, augers, wimbles, pincers, hook-pins, a square, a bevel, a pair of compasses, and a gauge, together with the level, square, and plumb-rule; besides these, planes (for making grooves, rebates, and mouldings), gimlets, pincers, a sledge-hammer, a maul or beetle, wedges, and a crow-bar may be considered useful auxiliaries, though they are not absolutely necessary to the performance of works of carpentry. Planing and other machines are used to diminish the great manual labour of working the surface of planks and boards, and of moulding, tenoning, and other similar operations; and so elaborate are some of these machines, that a four-panelled door can now be made complete in a couple of hours, which formerly was considered a good day’s work for a man. Circular-saws are employed for working up larger timbers; and for ripping up boards or scantlings of moderate thickness, they are now used in all workshops.

The fir timber in general use is imported from Memel, Riga, Dantzig, and Sweden. Memel timber is the most convenient for size, Riga the best in quality, Dantzig the strongest, and Swedish the toughest. Riga timber can always be depended upon. Red pine may be used wherever durability and strength are objects; Quebec yellow pine for light dry purposes. Iu selecting timber, spongy heart, porous grain, and dead knots are to be avoided; the brightest in colour, and where the strong red grain appears to rise on the surface, are the best to be chosen. For joists and main timbers, the best woods are from Dantzig, Memel, or Riga; for partitions and minor timbers, American red wood, which not being so strong as the Baltic timber, must be cut to a little larger size. For sleepers, window-sills, and some parts of a roof, oak is used; for framing, Christiania deals or battens; for panelling, Christiania white deal oι American yellow pine; for upper floors, Dram or Drammen and Christiania whites; for ground floors, Stockholm and Gefle yellows; for warehouse floors and staircases, Archangel and Onega planks; for best floors, St Petersburg, Onega, Dram, and Christiania battens. American deals should not be used for floors, as they are softer; and Swedish deals are bad for framing, as they warp. For interior finishings generally, Baltic red and white woods, and the American red and yellow pine, are to be preferred.

We must first proceed to consider the means by which form in the work of the carpenter is to be secured, and the connections by which the various strains are excited and communicated. The following practical remarks on various joints are abridged from the article by Prof. Robison in the former editions of this work.

The joinings practised in carpentry are almost infinitely various, and each has advantages which make it preferable in some circumstances. Many varieties are employed merely to please the eye. We do not concern ourselves with these; nor shall wc consider those which are only employed in connecting small works, and can never appear on a great scale; yet even in some of these, the skill of the carpenter may be discovered by his choice; for in all cases it is wise to make every, even the smallest, part of his work as strong as the materials will admit. He will be particularly attentive to the changes which will necessarily happen by the shrinking of timber as it dries, will consider what dimensions of his framings will be affected by this and what will net, and will then dispose the pieces which are less essential to the strength of the whole in such a manner that their tendency to shrink shall be in the same direction with the shrinking of the whole framing. If he do otherwise, the seams will widen, and parts will be split asunder. He will dispose his boardings in such a manner as to contribute to the stiffness of the whole, avoiding at the same time the giving them positions which will produce lateral strains on truss beams which bear great pressures; recollecting, that although a single board has little force, yet many united have a great deal, and may frequently perform the office of very powerful struts.

Our limits confine us to the joinings which are most essential for connecting the parts of a single piece of a frame (when it cannot be formed of one beam, either for want of the necessary thickness or length), and the joints for connecting the different sides of a trussed frame.

Much ingenuity has been bestowed on the manner of building up a great beam of many thicknesses, and many singular methods are practised; but when we consider the manner in which the cohesion of the fibres performs its office, we see that the simplest are formed on the same principles as the most refined, and they are less apt to induce false notions of the strength of the assemblage. Thus, were it required to build up a beam for a great lever or a girder, so that it may act nearly as a beam of the same size of one log, it may either be done by plain joggling, as in Plate XXII. fig. 1, A, or by scarfing, as in B or C. If it is to act as a lever, having the gudgeon on the lower side at C, we believe that most artists will prefer the form B and C. We may frequently gain a considerable accession of strength by this building up of a beam, especially if the part which is stretched by the strain be of oak, and the other part be fir. Fir being so much superior to oak as a pillar, and oak so much preferable as a tie, this construction seems to unite both advantages. But much better methods of making powerful levers, girders, &c., are obtained by trussing. Observe that the efficacy of both methods depends entirely on. the difficulty of causing the piece between the cross joints to slide along the timber to which it adheres. Therefore, if this be moderate, it is wrong to make the notches deep; for as soon as they are so deep that their ends have a force sufficient to push the slice along the line of junction, nothing is gained by making them deeper; and this requires a greaterexpenditure of timber.

Scarfings of beams are frequently made oblique, as in Plate XXII. fig. 2; but this seems a bad practice. It begins to yield at a point where the wood is erippled and splintered off, or at least bruised out a little. As the pressure increases, this part, by squeezing broader, causes the solid parts to rise a little upwards, and gives them some tendency, not only to push their antagonists along the base, but even to tear them up a little. For similar reasons we disapprove of the favourite practice of many artists to make the angles of their scarfings acute, as in fig. 3. This often causes the two pieces to tear each other up. The abutments should always be perpendicular to the directions of the pressures. This law is also to be extended to the abutments of different pieces of a frame, and the artist must even attend to the shrinking of the timbers by drying. When two timbers abut obliquely, the joint should be most full at the obtuse angle of the end; because, by drying, that angle grows more obtuse, and the beam would then be in danger of splintering off at the acute angle.

It is evident that the nicest work is indispensably necessary in building up a beam. The parts must abut on each other completely, and the smallest play or void takes away the whole efficacy. It is usual to give the abutting joints a small taper to one side of the beam, so that they may require moderate blows of a maul to force them in, and the joints may be perfectly close when the external surfaces are even on each side of the beam. But we must not exceed in the least degree, for a very taper wedge has great force; and if the pieces be driven together by very heavy blows, the whole is left in a state of violent strain, and the abutments are perhaps ready to splinter off by a small addition of pressure. It is not unusual to leave some abutments open enough to admit a thin wedge reaching through the beam. Nor is this a bad practice, if the wedge is of material which is not compressed by the driving or the strain of service. Iron would be preferable for this purpose, and for the joggles, were it not that, by its too great hardness, it cripples the fibres of timber to some distance. In consequence of this it often happens, that in beams which are subjected to desultory and sudden strains (as in the levers of reciprocating engines), the joggles or wedges widen the holes, and work themselves loose; therefore skilful engineers never admit them, and indeed admit as few bolts as possible, for the same reason; but when resisting a steady or dead pull, they are not so improper, and are frequently used.

Beams are built up, not only to increase their dimensions in the direction of the strain (which we have hitherto called their depth), but also to increase their breadth, or the dimensions perpendicular-to the strain. Sometimes the breadth of girder is doubled, if it is thought too weak for its load, and when the thickness of the flooring must not be increased.

The mast of a great ship of war must be made bigger athwartship, as well as fore and aft. This is one of the nicest problems of the art; and professional men are by no means agreed in their opinions in regard to it. We shall content ourselves here with exhibiting the different methods. The most obvious and natural method is that shown in Plate XXII. fig. 4. It is plain that (independent of the connection of cross bolts, which are used in them all when the beams are square) the piece C cannot bend in the direction of the plane of the figure without bending the piece D along with it. This method is much used in the French navy; but it is undoubtedly imperfect. Fig. 5 exhibits another method. The two halves of the beam are tabled into each other in the same manner as in fig. 1. It is plain that this will not be affected by any unequal swelling or shrinking, because this is insensible in the direction of the fibres; but when bent in the direction a b, the beam fig. 4 is weaker than bent in the direction cf. Each half of fig. 4 has, in every part of its length, a thickness greater than half the thickness of the beam. It is the contrary in the alternate portions of the halves of fig. 5. When one of them is bent in the direction AB, it is plain that it drags the other with it by means of the cross butments of its tables, and there can be no longitudinal sliding. But unless the work is accurately executed, and each hollow completely filled up by the table of the other piece, there will be a lateral slide along the cross joints sufficient to compensate for the curvature; and this will hinder the one from compressing or stretching the other in conformity to this curvature.

The imperfection of this method is so obvious that it has seldom been practised; but it has been combined with the other, as is represented in fig. 6, where the beams are divided along the middle, and, the tables in each half are alternate, and alternate also with the tables of the other half. Thus 1, 3, 4 are prominent, and 5, 2, 6 are depressed. This construction evidently puts a stop to both slides, and obliges every part of both pieces to move together, a b and c d show sections of the built-up beam corresponding to AB and CD. No more is intended in this practice by any intelligent artist, than the causing the two pieces to act together in all their parts, although the strains may be unequally distributed on them. Thus, in a built-up girder, the binding joists are frequently mortised into very different parts of the two sides. But many seem to aim at making the beam stronger than if it were of one piece; and this inconsiderate project has given rise to many whimsical modes of tabling and scarfing.

The practice in the British dockyards is somewhat different from any of these methods. The pieces are tabled as in fig. 6, but the tables are not thin parallelopipeds, but thin prisms. The two outward joints or visible seams are straight lines, and the table 1 rises gradually to its greatest thickness in the axis. In like manner, the hollow 5, for receiving the opposite table, sinks gradually from the edge to its greatest depth in the axis. Plate XXII., fig. 7, No. 1, represents a section of a round piece of timber built up in this way, where the full line EF, GH is the section corresponding to AB of fig. 6, and the dotted line EG, EH is the section corresponding to CD. This construction, by making the external seam straight, leaves no lodgment for water, and looks much fairer to the eye; but it appears to us that it does not give so firm a hold when the mast is bent in the direction EH. The exterior part3 are most stretched and most compressed by this bending; but there is hardly any abutment in the exterior parts of these tables. In the very axis, where the abutment is the firmest·, there is little or no difference of extension and compression. But this construction has an advantage, which, we imagine, much more, than compensates for these imperfections, at least in the case of a round mast; it will draw together by hooping incomparably better than any of the others.

Joggles of elm are sometimes used in the middle of the large tables of masts; and when sunk into the firm wood near the surface, they must contribute much to the strength. But it is very necessary to employ wood not much harder than the pine, otherwise it will soon enlarge its bed and become loose, for the timber of these large trunks is very soft.

The most general reason for piecing a beam is to increase its length. This is frequently necessary, in order to procure tie-beams for very wide roofs. Two pieces must be scarfed together. Numberless are the modes of doing this, and almost every master carpenter has his favourite nostrum. Some of them are very ingenious; but here, as in other cases, the most simple are commonly the strongest. We do not imagine that any, the most ingenious, is equally strong with a tic consisting of two pieces of the same scantling laid over each other for a certain length, and firmly bolted together. We acknowledge that this will appear an artless and clumsy tie-beam, but it will be stronger than any that is more artificially made up of the same thickness of timber. The next simplest and most obvious scarfing is that represented in Plate XXII., fig. 8, Nos. 1 and 2. If considered merely as two pieces of wood joined, it is plain that, as a tie, it has but half the strength of an entire piece, supposing that the bolts (which are the only connections) are fast in their holes. No. 2 requires a bolt in the middle of the scarf to give it that strength, and in every other part is weaker on one side or the other. If the bolts were sufficiently numerous and sufficiently firm, so as to produce a great degree of adhesion or of friction between the parts, this joint might be made almost as strong as the entire beam, since there is nothing to prevent the co-operation of each side with the other throughout its extent; but much of the strength would be lost if the bolts became loose, even in an inconsiderable degree. But the bolts are very apt to bend by the violent strain, and require to be strengthened by uniting their ends by iron plates,—in which case it is no longer a wooden tie. The form of No. 1 is better adapted to the office of a pillarthan No. 2, especially if its ends be formed in the manner shown in the elevation No. 3. By the sally given to the ends, the scarf resists an effort to bend it in that direction. Besides, the form of No. 2 is unsuitable for a post, because the pieces by sliding on each other by the pressure are apt to splinter off the tongue which confines their extremity. Figs. 9 and 10 exhibit the most approved form of a scarf, whether for a tie or for a post. The key represented in the middle is not essentially necessary; the two pieces might simply meet square there. This form, without a key, needs no bolts (although they strengthen it greatly), but, if worked very true and close, and with square abutments, will hold together, and will resist bending in any direction. But the key is a very great improvement, and will force the parts together with perfect tightness, but it must not be over driven. The form of fig. 9 is by far the best (it is sometimes said to be tabulated, that is, to render the joints as close as possible, and the juncture more independent of any bolts which might be placed similarly to those in fig. 8, No. 1),—because the triangle of fig. 10 is much more readily splintered off by the strain or by the key than the square wood of fig. 9. It is far preferable for a post, for the reason given in speaking of fig. 8, No. 1 and No. 2. Both may be formed with a sally at the ends equal to the breadth of the key. In this shape fig. 9 is well suited for joining the parts of the long corner posts of spires and other wooden towers. Fig. 9, No. 2 differs from No. 1 only by having three keys; the principle and the longitudinal strength are the same. The long scarf of No. 2, tightened by the three keys, enables it to resist bending much better.

None of these scarfed tie-beams can have more than one third of the strength of an entire piece, unless with the assistance of iron plates; for if the key be made thinner than one-third, it has less than one-third of the fibres to pull by We are confident, therefore, that when the heads of the bolts are connected by plates, the simple form of fig. 8, No. 1, is stronger than those more ingenious scarfings. It may be strengthened against lateral bending by a little tongue, or by a sally, but cannot have both.

The strongest of all methods of piecing a tie-beam would be to set the parts end to end, and grasp them between other pieces on each side, as in Plate XXIII., fig. 1. This the ship-carpenter calls fishing a beam; it is a frequent practice for occasional repairs. Perronet used it for the tie-beams or stretchers by which he connected the opposite feet of a centre, which was yielding to its load, and had pushed aside one of the piers above 4 inches

Where the beams stand square with each other, and the strains are square with the beams and in the plane of the frame, the mortise and tenon is the most perfect junction. A pin is generally put through both in order to keep the pieces united, in opposition to any force which tends to part them. Every carpenter knows how to bore the hole for this pin, so that it shall draw the tenon tight into the mortise, and cause the shoulder to butt close, and make neat work; and he knows the risk of tearing out the bit of the tenon beyond the pin, if he draw it too much. We may just observe, that square holes and pins arc much preferable to round ones for this purpose, bringing more of the wood into action, with less tendency to split it.

Ship-carpenters have an ingenious method of making long wooden bolts, not passing completely through, which take a very fast hold, though not nicely fitted to their holes, which they must not be, lest they should be crippled in driving. They call it fox-tail wedging. They stick into the point of the bolt T, Plate XXIII., fig 2, thin wedges of hard wood, so as to project a proper distance; when these reach the bottom of the hole by driving the bolt, they split the end of it, and squeeze it hard to the side. This may be practised with advantage in carpentry. If the ends of the mortise are widened inwards, and a thin wedge be put into the end of the tenon, it will have the same effect, and make the joint equal to a dove-tail; but this risks the splitting the piece beyond the shoulder of the tenon, which would be unsightly, and may be avoided by two very thin wedges a and c being struck in near its angles, projecting equally; at a very small distance within these are to be placed two shorter ones δ, d, and more within these if necessary. In driving this tenon, the wedges a and c will take first, and split off a thin slice, which will easily bend without breaking. The wedges b, d will act next, and have a similar effect, and the others in succession. The thickness of all the wedges taken together must be equal to the enlargement of the mortise towards the bottom.

When the strain is transverse to the plane of the two beams, great care must be taken by the artist in placing his mortise A mortise in a girder for receiving the tenon of a binding-joist of a floor should be as near the upper side as possible, because the girder becomes concave on that side by the strain. But as this exposes the tenon of the binding-joist to the risk of being torn off, we are obliged to mortise further down. The form in Plate XXIII., fig. 3, generally given to this joint is extremely judicious. The sloping part a b gives a very firm support to the additional bearing e d, without much weakening of the girder. This form should be copied in every case where the strain has a similar direction

The joint that most of all demands the careful attention of the artist is that which connects the ends of beams, one of which pushes the other very obliquely, putting it into a state of extension. The most familiar instance of this is the foot of a rafter pressing on the tie-beam, and thereby drawing it away from the other wall. When the direction is very oblique (in which case the extending strain is the greatest), it is difficult to give the foot of the rafter such a hold of the tie-beam as to bring many, of its fibres into the proper action. There would be little difficulty if we could allow the end of the tie-beam to project to a small distance beyond the foot of the rafter; but, indeed, the dimensions which are given to tiebeams for other reasons are always sufficient to give enough of abutment when judiciously employed. Unfortunately this joint is very liable to fail from the effects of the weather. It is much exposed, and frequently perishes by rot, or becomes so soft and friable that a very small force is sufficient either for pulling the filaments out of the tie-beam, or for crushing them together. We are therefore obliged to secure it with particular attention, and to avail ourselves of every circumstance of construction.

One is naturally disposed to give the rafter a deep hold by a long tenon, but it has been frequently observed in old roofs that such tenons break off. Frequently they are observed to tear up the wood that is above them, and push their way through the end of the tie-beam. This in all probability arises from the first sagging of the roof, by the compression of the rafters and of the head of the kingpost. The head of the rafter descends, and the angle with the tie-beam is diminished by the rafter revolving round its step in the tie-beam. By this motion the heel or inner angle of the rafter becomes a fulcrum to a very long and powerful lever much loaded. The tenon is the other arm, very short; and being still fresh, it is therefore very powerful. It therefore forces up the wood that is above it, tearing it out from between the cheeks of the mortise, and then pushes it along. Carpenters have therefore given up long tenons, and give to the toe of the tenon a shape which abuts firmly, in the direction of the thrust, on the solid bottom of the mortise, which is well supported on the under side by the wall-plate. This form, represented in Plate XXIII., fig. 4, has no tendency to tear up the end of the mortise. The tenon has a small portion a b cut perpendicular to the surface of the tie-beam, and the rest b c is perpendicular to the rafter.

But if the tenon is not sufficiently strong (and it is not so strong as the rafter, which is thought not to be stronger than is necessary), it will be crushed, and then the rafter will slide out along the surface of the beam. It is therefore necessary to call in the assistance of the whole rafter. It is in this distribution of the strain among the various abutting parts that the varieties of joints and their merits chiefly consist. We can only mention a few here that have met with most general approval.

The aim in fig. 5, Plate XXIII., is to make the abutments exactly perpendicular to the thrusts. The action is the same as against the joggle on the head or foot of a king-post. This is a very effectual joint; it is not, however, much practised. It is said that the sloping seam at the shoulder lodges water; but the great reason seems to be a secret notion that it weakens the tie-beam. Fig. 6 exhibits a form that is more general, but certainly worse. The shoulder-joint is sometimes formed like the dotted line ab edef g of fig. 6. This is much more agreeable to the true principle, and would be a very perfect method, were it not that the intervals b d and df are so short that the little wooden triangles b ed, def will be easily pushed off their bases b d, df. Fig. 7, No. 1, seems to have the most general approbation, but we fail to perceive its peculiar merits. It is the joint recommended by Price, and copied into books of carpentry as the true joint for a rafter foot. The visible shoulder-joint is flush with the upper surface of the tie-beam. The angle of the tenon at the tie nearly bisects the obtuse angle formed by the rafter and the beam, and is therefore somewhat oblique to the thrust. The inner shoulder ac is nearly perpendicular to b d. The lower angle of the tenon is cut off horizontally as at e d. Fig. 8 is a section of the beam and rafter foot, showing the different shoulders. Fig. 7, No. 2, is a simpler, and in our opinion a preferable joint. We observe it practised by the most eminent carpenters for all oblique thrusts; but it surely employs less of the cohesion of the tie-beam than might be used without weakening it, at least when it is supported on the other side by the wall-plate. Fig. 7, No. 3, is also much practised by the best carpenters. Fig. 9, No. 1, is proposed by Mr Nicholson as preferable to fig. 7, No. 3, because the abutment of the inner part is better supported. This is certainly the case, but it supposes the whole rafter to go to the bottom of the socket, and the beam to be thicker than the rafter. Some may think that this will weaken the beam too much, when it is no broader than the rafter is thick; in which case they think that it requires a deeper socket than Nicholson has given it. Perhaps the advantages of Nicholson’s construction may be had by a joint like fig. 9, No. 2.

Whatever is the form of these butting joints, great care should be taken that all parts bear alike; and the artist will attend to the magnitude of the different surfaces. In the general compression the greater surfaces will be less compressed, and the smaller will therefore change most. When all has settled, every part should be equally close. Because great logs are moved with difficulty, it is very troublesome to try the joint frequently to see how the parts fit; therefore we must expect less accuracy in the interior parts. This should make us prefer those joints whose efficacy depends chiefly on the visible joint. It appears from all that has been said on i this subject, that a very small part of the cohesion of the tie-beam is sufficient for withstanding the horizontal thrust of a roof, even though very low pitched. If, therefore, no other use is made of the tie-beam, one much slenderer may be used, and blocks may be firmly fixed to the ends, on which the rafters might abut, as they do on the joggles on the head and foot of a king-post. A tie-beam may have to carry a floor or ceiling (sometimes the workshops and store-rooms of a theatre), and therefore requires a great scantling, but frequently beams have little to do, and contain an unnecessary quantity of timber. It is therefore of importance to ascertain the most perfect manner of executing such a joint, and we have directed the attention to the principles that are really concerned in the effect. In all hazardous cases the carpenter calls in the assistance of iron straps; and they are frequently necessary, even in roofs, notwithstanding this superabundant strength of the tie-beam. But this is generally owing to bad construction of the wooden joint, or to the failure of it by time.

There needs but little to be said of the joints at a joggle worked out of solid timber; they are not near so difficult as the last. When the size of a log will allow the joggle to receive the whole breadth of the abutting brace, it ought certainly to be made with a square shoulder; or, which is still better, an arch of a circle having the other end of the brace for its centre. Indeed, this in general will not sensibly differ from a straight line perpendicular to the brace. By this circular form the settling of the roof makes no change in the abutment; but when there is not sufficient stuff for this, we must avoid bevel joints at the shoulders, because these always tend to make the brace slide off. The brace in Plate XXIII., fig. 10, No. 1, must not be joined as at b, but as at a, or in some equivalent manner.

When the very oblique action of one side of a frame of carpentry does not extend, but compresses, the piece on which it abuts, there is no difficulty in the joint. Indeed a joining is unnecessary, and it is enough that the pieces abut on each other; and we have only to take care that the mutual pressure be equally borne by all the parts, and that it do not produce lateral pressures, which may cause one of the pieces to slide on the butting joint. A very slight mortise and tenon is sufficient at the joggle of a king post with a rafter or straining beam. It is best, in general, to make the butting plain, bisecting the angle formed by the sides, or else perpendicular to one of the pieces. In fig. 10, No. 2, where the straining beam a b cannot slip away from the pressure, the joint a is preferable to b, or indeed to any uneven joint, which never fails to produce very unequal pressures on the different parts, by which some are crippled, others are splintered off, &c.

When it is necessary to employ iron straps for strengthening a joint, considerable attention is necessary that we may place them properly. The first thing to be determined is the direction of the strain. This must be resolved into a strain parallel to each piece, and another perpendicular to it; and then the strap which is to be made fast to any of the pieces must be so fixed that it shall resist in the direction parallel to the piece. Frequently this cannot be done; but we must come as near to it as we can. We can hardly give any general rules. Fig. 30 shows the nature of the strap or stirrup by which the king-post carries the tie-beam. The strap that we observe most generally ill placed is that which connects the foot of the rafter with the beam. It only binds down the rafter, and does not act against its horizontal thrust. It should be placed farther back on the beam, with a bolt through it, which will allow it to turn round. It should embrace the rafter almost horizontally near the foot, and should be notched square with the back of the rafter. It is represented in fig. 11, Plate XXIII. By moving round the eye-bolt, it follows the rafter, and cannot pinch and cripple it, which it always does iu its ordinary form. We are of opinion that straps which have eye-bolts in the very angles, and allow all motion round them, are of all the most perfect. A branched strap, such as may at once bind the king-post and the two braces which butt on its foot, will be more serviceable if it have a joint. When a roof warps, those branched straps frequently break the tenons, by affording a fulcrum in one of their bolts. An attentive and judicious artist will consider how the beams will act on such occasions, and will avoid giving rise to these great strains by levers. In the foregoing reasoning upon the direction of straps, regard has been had especially to the economizing of their immediate strength; but it may happen that the principal purpose of the strap will be answered by its pressing the rafter firmly upon the beam, and this effect may be produced by a certain deviation from the horizontal position, with but little diminution of the strength of the strap,—a deviation which has also the advantage of allowing the strap to embrace the whole of the beam, without weakening it by driving a bolt through it. We must not, however, run the risk of crippling the end of the . beam. A skilful carpenter never employs many straps, considering them as auxiliaries foreign to his art, and subject to imperfections in workmanship which he cannot discern or amend. We must refer the reader to ^Nicholson’s Carpenter and Joiner’s Assistantiox a more particular account of the various forms of stirrups, screwed rods, and other iron-work, for carrying tie-beams, &c.

The diagrams of Plate XXIV. will illustrate the use of the before-described joints on a smaller scale in the further operations of the carpenter’s work.

Ordinary scarfing is the cutting away equally from the ends, but on the opposite sides, of two pieces of timber, for the purpose of tying or connecting them lengthwise, and is done to wall-plates and bond-timber. The usual mode is by cutting about three-fifths through each piece on the upper face of the one and the under face of the other, about 6 or 8 inches from the end, as in fig. 1, Plate XXIV., transversely, making what is technically termed a calf ox kerf, and longitudinally from the end, from two-fifths down on the same side, so that the pieces lap together with a sort of half dovetail. Theheavy supervening weight of the wall and joists renders it impossible that they should be drawn apart without tearing the fibres asunder or lifting the weight. Nevertheless these joints are generally spiked, and it is always required that they be made to fall in or under a pier. Notching is either square or dovetailed; it is used in connecting the ends of wall-plates and bond-timber at the angles, in letting joists down on beams or binders, purlines on principal rafters, àc. Nos. 1, 2, 3, 4, and 5, fig. 2, show varieties of notches applied as we have described No. 1 is a simple square notch; No. 2, a dovetailed notch. No. 3 is the notch most commonly used; it is similar to No. 1, but that the ends are allowed to run on so that the one piece grasps the other, and each forms a cog to the other. No. 4 is an oblique-angled, dovetailed notch; and No. 5 shows how joists are notched or let down on beams and binders, and purlines on principal rafters. A notch is cut into the under edge of the joist or purline an inch or an inch and a half in depth, and considerably shorter than the beam, binder, or rafter is in thickness. Notches are also cut down on the upper angles of the bearing pieces, as long as the rider is thick, as deep as the notch before described of the latter is, and so far in as to leave a thickness on its own edge equal to the length of the notch in the riding joist or purline. In the diagram one joist is indicated in its place let down in the notch, and another indicates the notch in its own edge, and leaves exposed the notches in the binder. Cogging, or corking, as it is vulgarly termed, is the last-mentioned species of notch extended on one side, and leaving a narrow tooth or cog alone in the bearing-piece flush with its upper face, No. 1, fig. 3. It is used principally in tailing joists and beams on wall-plates and templets, and the cog is here made narrower, because the end of the joist or rider coming immediately beyond the plate, that part which forms the shoulder of the notch would be liable, on being strained, to be chipped off or torn away, if it were not kept as long as possible; and it is not of so much importance to guard against weakening a wall-plate which is supported along its whole length, as a beam, binder, or principal rafter, which rests on distant points alone. No. 2 of the same figure shows another mode of tailing on joists and beams by a dovetail notch, which, to distinguish it from the flat notches, Nos. 2 and 4, fig. 2, is called corking, or cogging also, though the operation certainly is not cogging. This is a good mode if the timber be so well seasoned as not to be likely to shrink more; but it would be improved by allowing the rider to take a bearing in a notch like that to No. 1 before the dovetail commenced, as at No. 3, for in the ordinary mode it is weakened in a point of great importance. Whatever notches and cogs for beams and joists are required in wall-plates and templets, should be made before tljey are set on or in a wall; for, as they are always bedded in mortar, anything that may break the set must be avoided. A cog-hold is best obtained through the agency of a chair of cast-iron, which should, however, be itself cogged or joggled to a stone templet laid in the wall under it, and be capped or covered by another broad flat stone, as an inverted templet, with a joggle from the chair running up into it.

Tenoning implies mortising also as a matter of course. They are the names of the two operations necessary to one result,—that of producing a connection between two pieces by inserting part of the end of one into a hole of similar size cut in the side or face of the other. A tenon is formed by cutting in on each side or edge of a piece of timber, near its end, transversely, to a certain depth, or rather, leaving a certain part of the breadth or depth uncut, and then cutting in longitudinally from the ends as far from each edge as the transverse cuts have been made in depth, thus removing two square prisms and leaving a third undivided. This is the tenon. An excavation in the side of a piece of timber, of a certain depth, in the direction of its thickness, parallel to its edges, and bounded lengthwise by lines at right angles to them, is a mortise. Tenons and mortises are made of exactly corresponding size, and are most frequently at equal distances from one or the other side or edge of the two pieces to be conjoined; and for the most part, too, every angle formed in the process of tenoning, both internal and external, is a right angle. Tenons are called joggles in some situations, when they are not intended to be borne upon, and their use is merely to keep the piece of timber to which they belong steadily in its place, without being liable to slight accidents from lateral pressure or violence. In combining timbers by means of mortises and tenons, to produce as great a degree of strength as possible, it must be obvious that the object to be kept in view is to maintain the end or tenon of the one as large and efficient as it may be, and weaken the other as little as possible in forming the mortise. For the efficiency of the mortised piece in a horizontal bearing, it is clear that as much of its thickness should be below the mortise as possible, as at α, fig. 4; for if it be put low, as at b, the superincumbent weight on the tenon would more readily split or rend it in the direction of the grain, as indicated; but the case is inverted with the tenoned pieces. With the mortise at a the tenon could only have the efficacy of so much of the piece to which it belongs as there is of it above its under surface, which is a very small part of its depth; whereas with the tenon at b it woιdd command the power of the greatest part of the depth. To guard as much as possible against the danger of too great a mortise and too small a tenon on one side and the other, and to obviate the difficulty arising from the efficiency of one or the other of the two pieces being affected by putting the tenon too high or too low, a compound, called a tusk tenon, is used for almost all horizontal bearings of any importance, especially to joists and binders, to trimmers, beams, girders, bressummers, &c. The body of the tenon in this is a little above the middle of the end, and it runs out 2, 3, or 4 inches, or more, as the case may require. Below it the tusk protrudes, and above it the shoulder is cut down at an obtuse angle with the horizontal line, giving the strength of the whole depth of the timber above the under tusk to the tenon, and giving it a bearing in a shallow mortise, whilst a greater depth of the mortised piece than the tusk rests on receives the body of the tenon, and so protects its comparatively narrow margin from undue pressure. The diagram No. 1, fig. 5, shows the tusk tenon, with the section of a beam into which it is mortised, and No. 2 indicates perspectively the appearance of the mortise in front. Pinning is the insertion of nearly cylindrical pieces of wood or iron through a tenon, to detain it in the mortise, or prevent it from being drawn out by any ordinary force. For this purpose the pin is inserted either in the body, or beyond the thickness, of the mortised piece, as indicated at a, fig. 5, or at a, fig. 6. Wedging (see b, b, No. 2, fig. 25) is the insertion of triangular prisms, whose converging sides are under an extremely acute angle, into or beside the end of a tenon, to make it fill the mortise so completely, or bind it so tightly, that it cannot be easily withdrawn. The wedging of tenons also assists in restoring to the mortised piece of timber much of the strength it had lost by the excision of so much of its mass, which indeed the tenon itself does if it fit closely in every direction; but the assistance of the wedge renders the restoration more perfect than the tenon could secure of itself, by compressing the fibres of both, longitudinally to those of the one, and transversely to those of the other, thus removing the tendency of the mortised piece to yield in any degree in the weakened part, though it cannot make up the loss in its tenacity occasioned by the scission of its fibres.

In scarfing, cogging, and notching, the shoulders are always cut in with the saw; but the cheek is for the most part struck out with the mallet and chisel, or adze, as may be most convenient. Tenons should be made entirely with the saw. Mortises are generally bored at the ends with an auger whose diameter equals their thickness; the intervening part is taken out with a wide chisel, cutting in the direction of the fibre; and the ends are squared down with a chisel whose breadth just equals the thickness of the mortise. Wood pins must be rent to insure the equal tenacity of their whole mass. Wedges are cut with the saw, but straight-grained stuff is always preferred for them.

Bond-timbers and wall-plates should be carefully notched together at every angle and return, and scarfed at every longitudinal joint. The scarf shown at fig. 1, Plate XXIV., is sufficient; and the notch at No. 3, fig. 2, may be preferred where notching is required; neither pinniDg nor nailing, however, can be of great use to either the notch or the scarf. Bond-timbers are passed along and through all openings, and are not cut out until such openings are to be permanently occupied, that is, by windows with their sash-frames, &c., because they assist in preventing irregular settlements, by helping to carry the weight of a heavy part along the substruction generally, instead of allowing it to press unduly upon the part immediately under it.

It is the duty of the carpenter to supply the bricklayer or mason with wood bricks in sufficient quantity, and to direct him where they should be placed to receive the joiner’s fittings, or the battening, which the carpenter himself may have to put up for the plasterer.

The carpenter makes and fixes or sets centres of all kinds, whether for single arches or niches, or even in bridge construction. Large centres are framed in distinct ribs, and are connected by horizontal ties; whilst small ones are made of mere boards cut to the required sweep, nailed together, and connected by battens notched into or nailed on their edges. Precision and stability are nevertheless equally and absolutely necessary, as it is impossible for an arch to be turned or set correctly on an incorrect or unstable centre.

Descriptions of various sorts of flooring are noticed in the earlier part of this article as for fireproof structures; and also under Brickwork and Mason-work. The timbers or framework of ordinary house and warehouse floors is called naked flooring, and it is distinguished as single, double, and framed. Of these the first, under ordinary circumstances, is the strongest.

Single flooring (Plate XXV. figs. 1, 2) consists of one row or tier of joists alone, bearing from one wall or partition to another, without any intermediate support, and receiving the flooring boards on the upper surface or edges of the joists, and the ceiling, if there be one, on the lower. Joists in single floors should never be less than 2 inches in thickness, because of their liability to be split by the brads or nails of the boards if they are thinner; and they should never be much more, because of the keying of the ceiling, which is injuriously affected by great thickness of the joists. Twelve inches from joist to joist is the distance generally allowed; that dimension, however, from centre to centre of the joists would be better Strength to almost any extent may be given by adding to the depth of the joists, and diminishing the distance between them; and they may be made firm, and be prevented from buckling or twisting, by putting struts between them. The struts are short pieces of batten, fig. 31, which should not be less than an inch, and need not be more than an inch and a half thick, and 3 or 4 inches wide, placed diagonally between the joists, to which they are nailed, in a double series, or crossing, as indicated by the full and dotted lines in Plate XXIV.

fig. 7; and they should be made to range in a right line, that none of their effect may be lost; and these ranges or rows should be repeated at intervals not exceeding 5 or G feet. The struts should be cut at the ends with exactly the same inclination or bevel, to fit closely. Great care should be taken, too, not to split the struts in nailing; but the trouble of boring with a gimlet is saved by making a slight nick or incision with a wide-set saw for each nail, of which there should not be less than two at each end; and the nails used should be clasp-nails. If the struts were notched into the joists, as in fig. 32, it would add very materially to their efficiency, but perhaps not in proportion to the additional labour it would involve. This strutting should be done to single flooring under any circumstances, as it adds materially to its firmness and indeed to its strength, by making the joists transmit any stress or pressure from one to another.

The efficiency of single flooring is materially affected by the necessity which constantly occurs in practice of trimming round fire-places and flues, and across vacuities. Trimming is a mode of supporting the end of a joist by tenoning it into a piece of timber crossing it, and called a trimmer, instead of running it on or into the wall which supports the ends of the other joists generally. A trimmer requires for the most part to be carried or supported at one or both of its ends by some of the joists, which are called trimming joists, and are necessarily made stouter than if they had to' bear no more than their own share of the stress. Commonly it is found enough to make the trimmers and trimming joists from half an inch to an inch thicker than common joists. In trimming, tusk tenons should be used; and the long tongue or main body of, the tenon should run not less than 2 inches through, and be draw-pinned and wedged, moreover, if it do not completely fill the mortise in the direction of the length of the latter.

The principal objection, however, to single flooring is, that sound readily passes through, the attachment of the boards above and of the ceiling below being to the same joists throughout. Another objection, and one already referred to, is the necessity of making the joists so thin, not to injure the ceilings, that they with difficulty receive the flooring brads in their upper edges without splitting. A partial remedy for both these disadvantages is found in a mode sometimes adopted of making every third or fourth joist an inch or an inch and a half deeper than the intervening joists; and to these, ceiling joists are notched and nailed, or nailed alone, as shown in Plate XXIV. fig. 7. This, by diminishing the number of points of contact between the upper and the lower surface, for the ceiljng joists must be carefully kept from touching the shallower joists of the floor, is less apt to convey sound from one story to another, and allows conveniently thin joists to be used for the ceiling without affecting those of the floor.

Double flooring (see Plate XXIV. fig. 8, Nos. 1 and 2, and Plate XXV. fig. 3) consists of three distinct series of joists, which are called binding, bridging, and ceiling joists. The binders in this are the real support of the floor; they run from wall to wall, and carry the bridging joists above and the ceiling joists below them. Binders need not be less and should not be much more than 6 feet apart, that is, if the bridging or flooring joists are not inordinately weak.' The bridging joists form the upper tier, and are notched down on the binders with the notch No. 5, Plate XXIV. fig. 2. The ceiling joists range under the binders, and are notched and nailed as shown at No. 1, fig. 8; but the notch must be taken entirely out of the ceiling joists, forthe lower face or edge of the binder may not be wounded by any means or on any account, and, moreover, no good would be gained in any other respect by doing so. When it is an object to save height in the depth or thickness of this species of floor, the ceiling joists may be tenoned into the binders, instead of being nailed to them; in this case the latter must be chase-mortised on one side, fig. 33, for the convenience of receiving the former when they are themselves set and fixed. A chase is a long wedge-formed groove of the breadth or thickness of the mortise, of which it is indeed an elongation, so that the tenon at one end of the ceiling joist being inserted in the regular mortise in the binder prepared for it, that at the other end is driven along the chase up to its place in the mortise in the next binder. When ceiling joists are thus chase-mortised, their lower or under faces are allowed to come a little below the under face of the binders, and the space across is firred down by slips not wider than the ceiling joists are thick. No. 2, fig. 8, shows a transverse compartment, or bay, of a floor in this manner; but it is not so good a one as the preceding; for, besides the weakening of the binders, by cutting so many mortises and chases in them, it is almost impossible to give the ceiling floor the degree of firmness and consistency it possesses in the other way, besides requiring the firring down on the binders. The same space would be better gained by cutting the bridging joists so much lower down; as they may, with the sort of notch indicated above, be let down fully half their depth without great injury to either bridging joists or binder, for they can always be made to fit tightly or firmly, and very little more labour is involved in notching deeply than slightly.

Flooring is said to be framed when girders are used together with binding, bridging, and ceiling joists (see Plate XXIV. fig. 9, Nos. 1 and 2, and Pl te XXV. fig. 4). Girders are large beams, in one or more pieces, according to the length required, and the size and strength of which timber can be procured. They are intended for longer bearings than mere binders may be trusted at, and may be strengthened by forming a built beam. The principle of constructing girders of any depth, says Tredgold, in his Carpentry, is the same as that of building beams, and when properly conducted they are as strong as any truss can be made of the same depth. The most simple method consists in bolting,'two pieces together, with keys between to prevent the parts sliding upon each other,—the upper one of hard compact wood, the lower of tough straight grained wood. The joints should be at or near the middle of the depth; the thickness of all the keys added together should be greater than one-third more than the whole depth of the girder; and if they be made of hard wood, the breadth should be about twice the thickness. They may be held together by bolts. Fig. 34 is a good form held by bands, and, if the upper timber be cut so as to be smaller towards the ends, would admit of these hoops being driven on till perfectly tight. In fig. 35 the parts are tabled or indented together instead of being keyed, and a king-bolt is added to tighten the joints. Girders may be further strengthened to almost any extent by trussing; but to be efficient, the height of the truss must always be greater than the depth of the beam itself, and the strength is increased by extending that height as the space or bearing increases. A truss is indeed a wooden arch, whose lateral thrust will of course be greater the smaller the angle subtended by it, and vice versa. It has been a commonly received opinion, that a truss less than the depth of a girder adds materially to its strength; but experiments have proved that very little advantage is gained by such a one, even when executed in the best manner, and that, badly executed, the beam or girder is weaker with the truss than without it. In some situations the flooring joists can be raised to a certain height to allow of the head of the truss, which is usually made of iron, being placed at a sufficient height to be truly efficient. Such is the trussed girder shown in fig. 36, intended for a great length. A common mode of strengthening a beam or bressummer, is to cut the timber in hale longitudinally, whereby any defects in the interior can be seen; then to reverse the pieces, end for end, and bolt them well together. Some additional strength is obtained by putting between the timbers a plate of wrought iron about the depth of the beam and about half an inch in thickness, and then bolting the three together, as in Plate XXIV. fig. 9, No. 3.

Binders are made dependent on the girders by means of double tusk tenons, and on and to them the bridging and ceiling joists are attached as above described. Plate XXIV. fig. 9, No. 1, shows the transverse section of a compartment or bay of a framed floor; No. 2 the same longitudinally of the girder and of the bridging and ceiling joists, and transversely of the binders. Plate XXV. fig. 1, is the plan of a single floor of joists tailing in on wall-plates with two chains of struts, and trimmed to a fire-place. Fig. 2 is a floor similar to fig. 1, with ceiling joists nailed to deeper flooring joists at intervals, as in Plate XXIV. fig. 7. Fig. 3 is the plan of a double floor; and fig. 4 is that of a framed floor of joists, bays of which are shown in section in Plate XXIV. figs. 8, 9. It is to be observed, with reference to the diagram fig. 9, No. 1, that binders ought not to be framed into the girders opposite to one another, as they are here shown to be as a matter of convenience, since the girder is unduly weakened by being mortised on both sides at the same place. Cast-iron shoes render mortising the one forming a tenon upon the other almost unnecessary; and in like manner cast-iron shoes laid into a wall upon stone templets give a good and safe bearing to the girders; but it is not everywhere that castiron shoes are attainable, and mortises and tenons may be made anywhere.

The above descriptions of the three sorts of flooring apply to floors which are to have a ceiling as in house building, or may be left open, as usual in warehouses. But in house building according to the practice of the mediaeval period, these timbers would be left exposed. They would all require to be planed smooth, the girders moulded, the binders partly so, and the joists perhaps only stop-chamfered, which is done by cutting the arris of tho timber to an angle along its whole length, but stopping short of the ends by a few inches, when it is returned into the arris by a cant. The underside of the joists in a framed floor may be lined with chamfered boarding or formed into panels and ornamented,—a boltel or a set of mouldings forming a frame or cornice all round against the binder. The girders would rest upon stone corbels, either moulded or decorated with foliage or figures, or all three united. Viollet le Duc, in his valuable Dictionnaire raisonné de l ’ Architecture, gives several examples of such a floor, of one of which we avail ourselves, from a house at Rheims of the 15th century (fig. 37). He gives an example also of a floor formed of a girder into which joists are laid formed of square timbers cut in half through the diagonal. These are fixed close together like a succession of v’s, thus vvvvv, and boarded over. The top of the angle space formed by two joists is filled up with a small angle fillet presenting a flat surface. The whole effect is unique.

In mediaeval carpenters’ work it was always the rule only to mould the useful members, and so it was also as regards the carving. Most of the old wood carving is so contrived as to be wrought out of the same plank or thickness as that which is moulded, or else is a separate piece of wood, in a spandril for instance, enclosed within the constructional members. In joining their work, which was of oak, they trusted entirely to tenoning and pinning with stout oak pins.

Although cast-iron columns and stanchions have for some years been preferred to timber posts as supports to girders of warehouse floors, lately the latter have again come into use from their known greater resistance to fire, whereas cast-iron soon succumbs to the great heat and the effects of water upon it. Such posts are usually made of fir or of oak, the dimensions of which vary according to their compound of crushing force and stiffness which is as 25 to 40. The caps to them should be long, so that they may not press into the girders, and if practicable, iron dowels should pass through the girders to catch the bases of the posts in the floor above.

Partitions of timber are called quartering partitions, and they are generally framed. Common quartering partitions, which rest on a wall or floor, and have nothing to carry, consist merely of a sill, a head, and common uprights called studs to receive the lath for plastering; these last may be simply joggled or tenoned into the head and sill, as shown in Plate XXIV. fig. 4, c, and stiffened by struts or stretching pieces put between them and nailed. When, however, a quartering partition is over a vacuity, or rests only on certain points, and has, moreover, to sustain a weight, a floor perchance, it is framed and trussed with king or queen posts and trussing pieces as to the tie-beam of a roof, and is thence called a trussed partition; and the filling in of common uprights or quarters for the laths is generally performed by joggling them at one end into either head or sill, and nailing them securely to the trussing pieces. In the diagram, Plate XXV. fig. 5, it is supposed that an opening or doorway is to be made in the partition, so that the timbers of the truss are placed around it with queenposts, and a small internal truss is put over the door-head to prevent it from sagging, and to carry the long part of the partition, which we supposed required to bear a floor, so that the partition acts also, in fact, the part of a trussed girder in the most available form. Pig. 6 presents another method of framing a similar partition. Such partitions should be set up in every story before the beams and joists of the floors are laid, that their horizontal timbers may be notched on to the wall-plates, and that the joists or binders may be notched on to them if occasion require it; but they should be fixed rather below than above the level of the wall-plates, because they are not liable to settle down so much as the walls, though even that will depend in a great degree on the nature of the walling, and its liability to yield. As the whole weight on partitions is supported by the principal posts, their scantlings must be first considered, which should be done in two different ways: first, when the studs are to be filled in with brickwork and rendered thereon, when they are called brick-nog partitions; or secondly, when they are to be lathed and plastered on both sides, or to be wainscoted. Thin partitions of wood only are called framed partitions and are considered in the portion relating to the joiner.

Roofing is another very important branch of the art of carpentry. The most simple form is a shed-roof or lean-to, which is merely obtained by pieces of wood being laid across in the position of an inclined plane to throw off the water. Rectangular buildings are usually covered by a roof in the form of a prism, the vertical section of which is an isosceles triangle. The height of this, or as it is technically called, the pitch of a roof, has varied in different ages, to suit the exigencies of the climate or the taste of the designer. A few examples showing the insertion of the foot of a principal rafter into a tie-beam, the struts into a post, and the heads of struts, are given in Plate XXIII.

To relate all the specialities which the carpenter may have to do in some particular buildings, as a church, for instance, would far exceed our limits. The mode of executing such things would be the same as already described, the style only making a difference in the result. Pewing or benching—the pulpit and reading-desk, stalls, screen work, font cover, gallery front, <fcc.—all depend on the architect’s designs. Again, shop fronts are now almost a speciality, together with shop-fittings; and among the minor things in a house are the cupboards, closets, bath, cisterns, kitchen-dresser, plate-rack, dust-bin when not of wholly of brick,—also stable fittings if the improved iron fittings be not used. Centering for arches and for bridges, wharf-walls, spires, turrets, belfries, church bell hangings, gables, are all embraced in carpenter’s work, as well as timber houses, the manner of framing which, and the names of the different timbers, will be found described in Le Muet’s work (1747) and others of that period, and illustrated in many valuable publications, by Nash, Richardson, Habershon, Clayton, Viollet de Due, Parker, Dollman, and others; and not least of such works in timber are the barn, porches, lych gates, palings, with chests and presses, and tables and chairs formerly.

Pugging floors, firring down joists, bracketing and cradling for plastering, and some other things, are operations performed indifferently by the carpenter or the joiner, as less or greater precision is required in the performance.

See Noxon, Mechanick Exercises, 4to., 1679; Godfrey Richards, Translation of the First Book of A. Palladio, 8vo, 1676; Smith, Carpenter's Companion, 8vo, 1735; Price, British Carpenter, 4 to, 1733-35; Batty Langley, Builder's Complete Assistant, 8vo, 1738, and his Builder's and Workman's Treasury of Designs, 4to, 1740; Swan, Carpenter's Complete Instructor, 4to, 1759 and 1768; Pain, British Palladio, fol., 1786 and 1804, and his Practical House Carpenter, 4to, 1774; Nicholson, Carpenter's New Guide, 4to, 1792, his Builder's New Director, 4to, 1824, and his Architectural Dictionary, 4to, 1835; Tredgold, Principles of Carpentry, edit, by Barlow, 4to, 1853; Weale, Carpentry, 4to, 1849; Newland, Carpenter's Assistant, kc., fol., 1860; Laxton, Examples of Building Construction, large fol., 1855-58; Tarbuck, Encyclopoedia of Practical Carpentry and Joinery, kc., 4to, 1857-59; A. W.

Pugin, Chancel Screens, 4to, 1851, and his Details of Ancient Timber Houses, 4to, 1836; Bury, Ecclesiastical Woodwork, 4to, 1847; Brandon, Analysis of Gothic Architecture, 4to, 1849; Dollman, Ancient Pulpits, 4to, 1849; A. Pugin, Ornamental Gables, 4to, 1831; and the following foreign publications: Jousse, Le Theatre, de Tart de Charpentier, fol., 1650; Le Muet, Manière de bien bastir, fol., 1623, translated by Pricke, fol., 1670 and 1675; Emy, L'Art de la Charpenterie, fol., 1841-42; Krafft, L'Art de la Charpenterie, fol., 1805; L'Art de la Charpente, fol., 1819-22, and Supplement by Thiollet, fol., 1840; Viollet de Duc, Dictionnaire, 8vo, 1857, &c.

Joinery.

Joinery is one of the useful arts which contributes most materially to the comfort and convenience of man. As the arts of joinery and carpentry are often followed by the same individual, it appears at first view natural to conclude that the same principles are common to both these arts; but a closer examination of their objects leads to a different conclusion. The art of carpentry is directed almost wholly to the support of weight or pressure, and therefore its principles must be found in the mechanical sciences. In a building it includes all the rough timberwork necessary for support, division, or connection; and its proper object is to give firmness and stability. The art of joinery has for its object the addition in a building of all the fixed wood-work necessary for convenience or ornament. The joiner’s works are many of them of a complicated nature, and require to be executed in an expensive material; therefore joinery requires much skill in that part of geometrical science which treats of the projection and description of lines, surfaces, and solids, as well as an intimate knowledge of the structure and nature of wood. A man may be a good carpenter without being a joiner at all; but he cannot be a joiner without being competent, at least, to all the operations required in carpentry. The rough labour of the carpenter renders him in some degree unfit to produce that kind of accurate and neat workmanship which is expected from a modern joiner; but it is no less true, that the habit of neatness and the great precision of the joiner make him a much slower and less profitable workman than the practised carpenter in works of carpentry. In carpentry, as before observed, framing owes its strength to the form and position of its parts; but in joinery, the strength of a frame depends upon the strength of the joinings. The importance, therefore, of fitting the joints together as accurately as possible is obvious. It is very desirable that a joiner should be a quick workman, but it is still more so that he should be a good one; that he should join his materials with firmness and accuracy; that he should make surfaces even and smooth, mouldings true and regular, and the parts intended to move so that they may be used with ease and freedom. It is also of the greatest importance that the work, when thus put together, should be constructed of such sound and dry materials, and on such principles, that the whole should bear the various changes of temperature and of moisture and dryness, so that the least possible shrinkage or swelling should take place.

In early times very little that resembles modern joinery was known; every part was rude, and joined in the most artless manner. The first dawnings of the art appear in the thrones, stalls, pulpits, and screens of our cathedrals and churches; but even in these it is of the most simple kind, and is indebted to the carver for everything that is worthy of regard. Whether iu these monuments the carver and the joiner had been one and the same person we cannot now determine, though we imagine, from the mode of joining in some of them, that this was the case. With the revival of classic art great changes took place in every sort of construction. Forms began to be introduced in architecture which could not be executed at a moderate expense without the aid of new principles, and these principles were discovered and published by practical joiners. As might naturally be expected, these authors had but confused notions, with their scanty geometrical knowledge; and, accordingly, their descriptions are often obscure, and sometimes erroneous. The change from the heavy mullioned casement and its guard of iron bars to the sash windows necessitated some new method of protection, and boxing shutters were invented. The framed wainscot of small panels gave way to the large bolection moulded panelling. Heavy doors, which were fomerly hung on massive posts, or in jambs of cut stone, were now framed in light panels, and hung in moulded dressings of wood. The scarcity of oak timber, and the expense of working it, led to the importation of fir timber from the north, which gradually superseded all other material except for the choicest works. But the art is still far short of perfection, and in some respects it seems to have retrograded. It is seldom that large glued-up panels will now stand well. Mouldings of great girth givo at the mitres, doors wind, and skirtings shrink from the floors in a way seldom seen in old houses. The sashes, perhaps, are made better than the heavy barred windows of a century and a half ago. In no other respect, however, has joinery made the progress which has been made in other arts. The improved state of machinery has also done but little for its excellence, though the circular saw-bench, the planing-machines, the moulding-machines, and the mortising-machines have done much to reduce the cost of labour. This last machine was suggested in the seventh edition of this work (1830), attention having been drawn to the subject from the improvements in the art of blockmaking, and it is now used in most of the large establishments throughout the country.

The joiner operates with saws, planes, chisels, gouges, hatchet, adze, gimblets, and other boring instruments (which are aided and directed by chalked lines), gauges, squares, hammers, mallets, and a great many other less important tools; and his operations are principally sawing and planing in all their extensive varieties, setting out, mortising, dovetailing, &c. Descriptions of the tools, with instructions for using them, may be found in Moxon’s Mechanick Exercises, 4to, London, 1677-80, andin Nicholson’s Mechanical Exercises, London, 1812.

There is likewise a great range of other operations, none of which can be called unimportant, such as paring, gluing up, wedging, pinning, fixing, fitting, and hanging, and many things besides which depend on nailing, <fcc., such as laying floors, boarding ceilings, wainscoting walls, bracketing, cradling, firring, and the like. In addition to the wood on which the joiner works, he requires also glue, nails, brads, screws, and hinges,—and accessorily he applies bolts, locks, bars, and other fastenings,—together with pulleys, lines, weights, white-lead, hold-fasts, wall-hooks, <fcc., <fcc.

The joiners’ work for a house is for the most part prepared at the shop, where every convenience may be supposed to exist for doing everything in the best and readiest manner; so that little remains to be done when the carcass is ready, but to fit, fix, and hang, that is, after the floors are laid. The sashes and frames, the shutters, back flaps, backs, backs and elbows, soffits, grounds, doors, <kc., are all framed and put together, that is, wedged up and cleaned off, at the shop; the flooring boards are prepared, that is, faced, shot, and gauged with a fillister rebate; and the architraves, pilasters, jamb linings, skirtings, mouldings, <fcc., are all got out, that is, tried up, rebated, and moulded, at the shop. The joiner very often turne the house he has to fit up into a workshop ; for benches, and a fire for his glue-pot, are nearly all he requires, should he not have the now usual “general joiner” machine.

There is no art in which it is required that the structure and properties of wood should be so thoroughly understood as in joinery. The practical joiner, who has made the nature of timber his study, has always a most decided advantage over those who have neglected this most important part of the art.

It is well known that wood contracts less in proportion, in diameter, than it does in circumference; hence a whole tree always splits in drying. Mr Knight has shown that, in consequence of this irregular contraction, a board may be cut from a tree that can scarcely be made by any means to retain the same form and position when subjected to various degrees of heat and moisture. From the ash and the beech he cut some thin boards in different directions relatively to their tranverse septa, so that the septa crossed the middle of some of the boards at right angles, and lay nearly parallel with the surfaces of others. Both kinds were placed in a warm room, under perfectly similar circumstances. Those which had been formed by cutting across the tranverse septa, as at A in fig. 38, soon changed their form very considerably, the one side becoming hollow, and the other round; and in drying, they contracted nearly 14 per cent, in width. The other kind, in which the septa were nearly parallel to the surfaces of the boards, as at B, retained, with very little variation, their primary form, and did not contract in drying more than 3i per cent, in width. {Philosophical Transactions, part ii. for 1817; Philosophical Magazine, vol. 1. p. 437.)

As Mr Knight had not tried resinous woods, two specimens were cut from a piece of Memel timber; and to render the result of the observations more clear, conceive fig. 38 to represent the section of a tree, the annual rings being shown by circles. BD represents the manner in which one of our pieces was cut, and AC the other. The board AC contracted 3'75 per cent, in width, and became hollow on the side marked b. The board BD retained its original straightness and contracted only 0 - 7 per cent. The difference in the quantity of contraction is still greater than in hard woods. From these experiments, the advantages to be obtained merely by a proper attention in cutting out boards for panels, &c., will be obvious; and it will also be found that panels cut so that the septa are nearly parallel to their faces, will appear of a finer and more even grain, and require less labour to make their surfaces even and smooth. But as this system would necessitate the rejection of all but the heart of the tree for superior work, a method has been adopted which it is said was first used by the billiard-table makers. Let AC, fig. 39, represent the piece above referred to by the same letters. It will become hollow on the side marked b, no doubt because the rings of the wood when cut across are relieved from tension, and endeavour to expand themselves. To counteract this it is customary, in all good work, to rip the plank down the centre, and then to “turn the stuff inside out” as it is popularly called. This is done by reversing the wood, end for end, so as to bring the heart against heart, and the outside against outside, as is shown in fig. 40 (without which the glue joints are sometimes liable to fly), and also so as to reverse the circular parts of the grain.

In wood that has the larger transverse septa, as the oak, for example, boards cut as BD will be figured, while those cut as AC will be plain.

There is another kind of contraction in wood whilst drying, which causes it to become curved in the direction of its length. In the long styles of framing we have often observed it; indeed, on this account, it is difficult to prevent the style of a door, hung with centres, from curving, so as to rub against the jamb. A very satisfactory reason for this kind of curving has been given by Mr Knight, which also points out the manner of cutting out wood, so as to be less subject to this defect, which it is most desirable to avoid. The interior layers of wood, being older, are more compact and solid than the exterior layers of the same tree; consequently, in drying, the latter contract more in length than the former. This irregularity of contraction causes the wood to curve in the direction of its length, and it may be avoided by cutting the wood so that the parts of each piece shall be as nearly of the same age as possible. But as this would also necessitate the rejection of a great deal of stuff, a simpler method is found, which is always to turn the heart of the wood outwards. Thus, in framing a door, the heart should always go against the jambs, and the sap side to the panels.

Besides the contraction which takes place in drying, wood undergoes a considerable change in bulk with the variations of the atmosphere. In straight-grained woods the change in length is nearly insensible, and hence they are sometimes employed for pendulum rods; but the lateral dimensions vary so much that a wide piece of wood will serve as a rude hygrometer. The extent of variation decreases in a few seasons, but it is of some importance to the joiner to be aware that even in very old wood, when the surface is removed, the extent of variation is nearly the same as in new wood.

It appears from Rondelet’s experiments (R’Ärt de bâtir, article “Menuiserie,” tom. iv. p. 425, 1814), that in wood of a mean degree of dryness, the extent of contraction and expansion, produced by the usual changes in the state of the atmosphere, was, in fir wood, from ∙ 5 ⅜ π to 7 ⅛ of its width, and in oak, from τ ⅛ to ⅛∙ Consequently, the mean extent of variation in fir is τ ⅛ τ , and in oak, τ ∣- σ ; and, at this mean rate, in a fir board about 12⅜ inches wide, the difference in width would be -⅛th of an inch. This will show the importance of attending to the maxims of construction we have already laid before the reader; for, if a board of that width should be fixed at both edges, it must unavoidably split from one end to the other.

The kinds of wood commonly employed in joinery are —the oak, the different species of pine, mahogany, and sometimes lime-tree and poplar. Of the oak there are two species common in Britain; that which Linnaeus has named Quercus Robur is the most valuable for joiners’ work; it is of a finer grain, less tough, and not so subject to twist as the other kind. Oak is also imported from the Baltic ports, from Germany (that known as wainscot), and from America. These foreign kinds being free from knots, of a straighter grain, and less difficult to work, they are used in preference to British species. The greater part of joiners’ work is executed in fir imported from the north of Europe. Yellow fir is used for outside work, as doors and sashes, and for floors where there is likely to be much wear. Very good red pine deals have been imported from Canada. Inside work is almost always framed of white fir. Some very good panels when not too wide, and excellent mouldings, are made of American pine. White fir is often used for internal work, and yellow pine is much used for mouldings. The forest of Braemar, in Aberdeenshire, furnishes yellow fir of an excellent quality, little inferior to the best foreign kinds. For the general purposes of joinery, the wood of the larch seems to be the best; this useful tree thrives well on the Scottish hills. Some fine specimens of it have been obtained from Blair-Athol. It makes excellent steps for stairs, floors, framing, and most other articles. Mahogany, in joinery, is only used where painted work is improper, as for the hand-rails of stairs, or for the doors and windows of principal rooms. For doors it is not now so often used as it was formerly, its colour being found to be too gloomy to be employed in large masses. Lime-tree, and the different species of poplar, make very good floors for inferior rooms; and may often be used for other purposes, in places where the carriage of foreign timber would render it more expensive. Lime-tree is valuable for carved work, and does not become worm-eaten; but carving is at present seldom used in joinery.

From these timbers, the oak and fir especially, the joiner obtains the battens, fillets, boards, and planks, with which he performs all his works, cutting them into scantlings and thin deals as he requires them.

Battens are narrow boards running from half .an inch to an inch and a half or 2 inches thick, and from 3 to 6 or 7 inches wide. A piece of stuff of too small a scantling to be a batten is called a fillet. The term board is applied to sawed stuff when its width exceeds that of a batten, and its thickness does not exceed 2 inches or 2⅜ inches. The term plank is applied to large pieces of stuff whose width is great in proportion to their thickness, and whose thickness nevertheless does not exceed 3 or 4 inches. In London these terms are used in much more restricted senses than they are here described to mean, because of the fixed and regular sizes and forms in which stuff for the joiner’s use is for the most part brought to market there. A batten, to a London joiner, is a fine flooring board from an inch to an inch and a half in thickness, and just 7 inches wide. A board is a piece cut from the thickness of a deal whose width is exactly 9 inches; and nearly everything above that width, and not large enough to be called a scantling of timber, is a plank.

Mouldings, in the Roman and Italian styles, as used in joinery, are generally composed of parte of circles, and differ somewhat from those used in stone. (See Plates XIII., &c., illustrating the article Architecture, in vol. ii.) Mouldings are almost the only part of modern joiners’ work which can, in strictness, be called ornamental, and consequently that in which the taste of the workman is most apparent. The form of them should be distinct and varied, forming a bold outline of a succession of curved and flat surfaces, disposed so as to form distinct masses of light and shade. If the mouldings be of considerable length, a greater distinction of parts is necessary than in short ones. Those for the internal part of a building should not, however, have much projection; the proper degree of shade may always be given, with better effect, by deep sinkings judiciously disposed. The light in a room is not sufficiently strong to relieve mouldings, without resorting to this method; and hence it is that quirked and under-cut mouldings are so much esteemed. The following present the convex side to the eye fig. 41 is merely a rounded edge; fig. 42, of small size, is a bead; fig. 43, of larger size, a torus; and fig. 44 shows the torus and bead together. If there be a deep sinking under a bead (as fig. 45), it is called a quirked or cock bead; if there be two such sinkings, so as to show three-quarters of a circle in the bead, it is called (fig. 46) a double-quirked bead; two or more beads, side by side fas fig. 47) are called reeds; the fourth part of a circle, or half a bead (as fig. 48), is called an ovolo, or quarter round. A moulding composed of two convex parts is also called an ovolo, the upper part of the curve being continued round into the bed similar to a quirk, as fig. 44. In concave mouldings a simple curved grooving, as fig. 49, is called a hollow, and two or more such grooves are flutes, as fig. 50. A hollow forming the fourth part of a circle is called a cavetto, fig. 51; a deep hollow between two fillets, as used in base mouldings, is a scotia, fig. 52. Mouldings which are partly convex and partly concave, are of two sorts, the cyma recta, as figs. 53 and 54, and the cyma reversa or ogee, as figs. 55 and 56, which may be made of greater or less projection. Grecian mouldings are all similar in principle, but the parts are of conic sections instead of circles, as explained above, p. 473.

A plain square sinking on the edge of a board, as fig. 57, for the purposes of framing, is called a rebate; if away from the edge, as fig. 58, a groove; placed under a cap (as fig. 59), or as a necking (as fig. 60), it is called a fillet; three such fillets under an ovolo, when composing part of the capital of a column, are called annulets. In all kinds of framing the mouldings which rise above the styles are called bolection mouldings (see fig. 82).

The mouldings during the mediaeval period used by the carpenter and joiner, who were perhaps the same person, seldom varied from those cut by the mason, except that they were somewhat more refined and less in size, as appropriate to the material out of which they were to be cut. “They are such as would not be executed in any other material; they are sharp, delicate, minute, and quaintly under-cut. Every curve is subtle; every alternation of round and flat and hollow thoughtfully contrived, graceful, and yet vigorous; they are very often unlike any stone mouldings,” says Mr G. E. Street, in a lecture in 1865 on “English Woodwork in the 13th and 14th Centuries,” printed in the Transactions of the Royal Institute o∕ British Architects. “In the stalls at Selby there is an elaborate cap only 1⅜ inches in height; and at Winchester a band ∣ths of an iuch in height, and yet consisting of four distinct members, and showing in elevation as many as eight distinct lines.” The woodcuts appended will suffice to explain the author’s meaning. Fig. 61 is a mullion from stalls at Winchester Cathedral, and fig. 62 from St Mary’s Hospital at Chichester. Figs. 63 and 64 are arch mouldings from the same stalls; and fig. 65, the cornice of a screen in Old Shoreham church. Fig.

66 is a cap and base from the stalls at Winchester.

When an inclined or raking moulding is intended to join with a level moulding, at either an exterior or an interior angle, the form of the level moulding being given, it is necessary that the form of the inclined moulding should be determined, so that the corresponding parts of the surfaces of the two mouldings should meet in the same plane, this plane being the plane of the mitre. This may be otherwise expressed by saying that the mouldings should mitre truly together.

When the length of a joint at an angle is not considerable, it is sufficient to cut the joint in such a manner that when the parts are joined, the plane of the joint shall bisect the angle. This kind of joint is shown for two different angles, by fig. 67, and is called a mitre. When an angle of considerable length is to be joined, and the kind of work does not require that the joining should be concealed, fig. 68 is often employed; the small bead renders the appearance of the joint less objectionable, because any irregularities from shrinkage are not seen in the shade of the quirk of the bead. A bead upon an angle, where the nature of the work does not determine it to be an arris, is attended with many advantages; it is less liable to be injured, and admits of a secure joint without the appearance of one. Fig. 69 shows a joint of this description, which should always be used in passages. Fig. 70 represents a very good joint for an exterior angle, whether it be a long or a short one. Such a joint may be nailed both ways. But the joint represented by fig. 71 is superior to it; the parts, being drawn together by the form of the joint itself, can be fitted with more accuracy, and joined with certainty. The angles of pilasters are often joined by this last method. Interior angles are commonly joined as shown in fig. 72. If the upper or lower edge be visible, the joint is mitred, as in fig. 67, at the edge only, the other part of the joint being rebated, as in fig. 70. In this manner are put together the skirting and dado at the interior angles of rooms, the backs and backlinings of windows, the jambs of door-ways, and various other parts of joiners’work. Fig. 73 is an excellent method of joining angles for drawers, frames for lead cisterns, boxes, &c., and is commonly called a dovetail. If a portion of the junction is cut off at an angle of 45°, as fig. 74, while the portion at b is dovetailed, it is called a mitre dovetail; while if the portion at a (in fig. 75) passes the other portion at right angles, it is called a lap-dovetail. A very good joint is shown in fig. 76, the angles being brought together at an angle of 45°, two or more saw curfs are cut with a dovetail saw, and thin pieces of wood glued in as shown; this is called a keyed mitre.

Fig. 77 shows four methods for securing planks together as practised in France during the mediaeval period, from Viollet le Due’s Dictionnaire. He does not appear to show the junction formed by running a tongue of one piece through another piece and pinning it on the outside, as practised now in England in furniture, as tables, <fcc.

Glue is a viscid tenacious matter used as a cement to connect objects together. The common or animal glue is made from certain portions of animals reduced after certain processes by boiling to the required consistency, and dried in cakes. The best marine glue is composed of caoutchouc dissolved in naphtha, to which shellac is added, and heated until amalgamated. It is insoluble in water, sufficiently solid to give strength, and adhesive to an intense degree. Glue is used principally in putting framed work together, but not at all in fixing; and even for the former purpose it is much less used by good workmen than by bungling hands. When the stuff is well seasoned, and the trying up, setting out, mortising, and tenoning are well and accurately executed, there is no necessity for glue on the tenons and shoulders; the wedges alone need be glued, to attach them to the sides of the tenons, that their effect may not depend on mere compression. Joiners are generally furnished with a cramp, with which to force the joints of framing into close contact; it is either of wood acting by means of wedges, or of iron with a screw. This, too, is unnecessary with good work, every joint of which may be brought perfectly close without great violence of any kind. The cramp will sometimes give bad work the semblance of good, but it cannot make it really so. If any cracking and startiug be heard in the joiner’s work of a new building, it generally indicates one of two things: either the cramp has been required in putting the framing together, or, having been put together, it has' been forced out of winding in fixing, and the constrained fibres are seeking to regain their natural position. A good workman does not require cramp, nor will his work, if he has been supplied with seasoned stuff, ever require to be strained; and consequently the cracking and starting of joiners’ work indicate unfit stuff or bad work, or perhaps both, It is true that glued joints will sometimes fly; but when they do, there need be no hesitation in determining the presence of both bad work and stuff* in an improper state.

It is seldom possible to procure boards sufficiently wide for panels without a joint, on account of heart shakes, which open in drying. In cutting out panels, for good work, shaken wood should be carefully avoided. That part near the pith is generally the most defective. If the panels be thick enough to admit of a cross or feather tongue in the joint, one should always be inserted, for then, if the joint should fail, the surfaces will be kept even, and it will prevent light passing through. A very good way also is to glue a piece of strong canvas on the back of the panel when the work is not intended to be seen on both sides. Sometimes plane surfaces of considerable width and length are introduced in joiners’ work, as in dado, window backs, <fcc.; such surfaces are commonly formed of inch or inch and quarter boards joined with glue, and a cross or feather tongue ploughed into each joint. When the boards are glued together, and have become dry, tapering pieces of wood, called keys, are grooved in across the back with a dovetailed groove. These keys preserve the surface straight, and also allow it to shrink and expand with the changes of the weather. It would be an endless task to describe all the methods that have been employed to glue up bodies of such varied forms as occur in joinery; for every joiner forms methods of his own, and merely from his being most familiar with his own process, he will perform his work, according to it, in a better manner than by another, which to an unprejudiced mind has manifestly the advantage over it. The end and aim of the joiner, in all these operations, is to avoid the peculiar imperfections and disadvantages of his materials, and to do this with least expense of labour or material. The straightness of the fibres of wood renders it unfit for curved surfaces, at least when the curvature is considerable. Hence, short pieces are glued together as nearly in the form desired as can be, and the apparent surface is covered with a thin veneer; or the work is glued up in pieces that are thin enough to bend to the required form. Sometimes a thin piece of wood is bent to the required form upon a cylinder or saddle, and blocks are jointed and glued upon the back; when the whole is completely dry it will preserve the form that had been given to it by the cylinder. The curve should be made a little “quicker” than the curve intended, as the stuff will always spring back a trifle on being released. A piece of work glued up in thicknesses should be very well done; but it too often happens that the joints are visible, irregular, and in some places open; therefore other methods have been tried.

Large pieces of timber should never be used in joinery, because they cannot be procured sufficiently dry to prevent them splitting with the heat of a warm room. Therefore, the external part of columns, pilasters, and works of a like kind, should be formed of thin pieces of dry wood; and, if support be required, a post, or an iron pillar, may be placed within the exterior column. Thus, to form columns of wood, so that they shall not be liable to split, narrow pieces of wood are used, not exceeding 5 inches in width. These are jointed like the staves of a cask, and glued together, with short blocks glued along at each joint. Fig. 78 is a plan of the lower end of a column glued up in staves; the bevel at A is used for forming the staves, that at B is used for adjusting them when they are glued together. A similar plan must be made for the upper end of the column, which will give the width of the upper end of the staves. The bevels taken from the plan, as at A and B, are not the true bevels; but they are those generally used, and are very nearly true when the columns are not much diminished The same method may be adopted for forming large pillars for tables, <fcc. If a column have flutes, with fillets the joints should be in the fillets, in order to make the column as strong as possible; also, if a column be intended to have a swell in the middle, proper thickness of wood should be allowed for it. When columns are small they may be made of dry wood, and turned in a lathe, when they can be moulded at the same time. Balusters for stairs are made thus. To secure small columns against splitting, a hole should be bored down the axis of each column

If a piece of wood be boiled in water for a certain time, and then taken out and immediately bent into any particular form, and it be retained in that form till it be dry, a permanent change takes place in the mechanical relations of its parts; so that though, when relieved, it will spring back a little, yet it will not return to its natural form The same effect may be produced by steaming wood; but though both these methods have been long practised to a considerable extent in the art of ship-building, we are not aware that any general principles have been discovered either by experiment or otherwise, that will enable us to apply them in joinery, where so much precision is required. They do not seem to have been tried; and before they can be rendered extensively useful, the relation between the curvature to which the wood is bent, and that which it assumes when relieved, should be determined, and also the degree of curvature which may be given to a piece of a given thickness. The time that a piece of wood should be boiled or steamed, in order that it may be in the best state for bending, should be made the subject of experiments; and this being determined, the relation between the time and the bulk of the piece should be ascertained. A novel and very simple and effective way of boiling sash-bars or thin articles has been adopted, as shown in fig. 79. Take a p∣ece of common cast-iron pipe of sufficient diameter, stop up one end with a plug of wood driven tight, fill the pipe with water, raise one end in a sloping position, leaning it on a pile of bricks, and kindle a fire under the pipe. For the joiner’s purposes the process might perhaps be greatly improved by saturating the convex side of each piece with a streng solution of glue immediately after bending it. By filling, in this manner, the extended pores, and allowing the glue to harden thoroughly before relieving the pieces, they would retain their shape better.

The object in framing is, to reduce the wood into narrow pieces so that the work may not be sensibly affected by its shrinkage; and, at the same time, it enables us to vary the surface without much labour. Besides this, as the strains from the grain of the wood are in different directions, the work is prevented from winding on its face. From this view of the subject, the joiner will readily perceive that neither the parts of the frame nor the panels should be wide. And as the frame should be composed of narrow pieces, it follows that the panels should not be very long, otherwise the frame will want strength. The panels of framing should not be more than 15 inches wide and 4 feet long, and panels so large as this should be avoided as much as possible. The width of the framing is commonly about one-third of the width of the panel. Frames in joinery are usually connected by mortise and tenon joints, with grooves to receive the panels. Wainscoting, doors, window-shutters, &c., are framed in this manner.

In framing or framed work, the outer vertical bars which are mortised are called styles; and the transverse, those on whose ends the tenons are formed are called rails (Plate XXVI. fig. 2). In doors the open spaces or squares formed internally by the rails and styles are divided in the width by bars parallel to the styles. These are tenoned into the rails, and are called munnions or mountings, or, vulgarly, muntins. The frame being formed by trying up, setting up, mortising, and tenoning, the inner or face edges of the styles, and of the highest and lowest rails, and both edges of the muntins and of the inner rails, are grooved with the plough to receive the edges and ends of the filling-in parts or panels of the framework. Panels are either flat, raised, or flush (Plate XXVI. fig. 3). Flat panels are no thicker than the grooves into which they are fitted, and consequently their faces are as much below the surface of the framing as the groove is in from each side of the styles and rails. Raised panels are thicker than the groove in the framing, but are not so thick as to reach the surface; nor is the panel thickened through its whole extent. It fits exactly into the groove, and thickens gradually for an inch or two, and then sets off at a right angle with the surface, increasing suddenly three or four sixteenths of an inch. A panel may be raised on one side only, or on both sides. Flush panels are rebated down from one face to the distance the plough groove is in from the surface of the framing; and the back of a panel thus rebated on one side is worked down to be even with the other edge of the groove, leaving a tongue to fit it exactly; for if it be required to make panels flush on both sides, this is generally effected by filling in on the back or flattened side with an extraneous piece. Panels of external doors and shutters may be rendered more secure by boring them, and inserting iron wires, as noticed in the Transactions of the Society of Arts, vol. xxv. p. 106. Framing is not, however, often finished in the manner above described, especially with raised and flush panels; mouldings are generally introduced, and are either struck or worked in the solid substance of the framing, or are in separate pieces or slips, and laid in with brads. If a moulding be struck or laid in on one side only, and the other is left plain, the framing is described as moulded and square, a flat panel being in that case understood; if the panel be raised the framing will be described as moulded with a raised panel on one side, and square or flush on the other. It may be moulded with a flat panel, or moulded with a raised panel, on both sides; and the moulding may, as before intimated, be either struck in the solid or laid in any of the preceding cases. Mouldings which are laid in round the panels of framing are neatly mitred at the angles, and bradded, to appear as much as possible as if they were struck in the solid. In nailing or bradding the mouldings, the brads should be driven into the framework, and not into the panels. Framing with sunk panels, in some kinds of work, has the edges of the rails and styles either stop-chamfered or slightly curved. With a flush panel the moulding is always either a bead, or a series of beads called reeds; and is, in the case of a single bead, which is most common, always struck on the solid frame, and the work is called bead-flush; but reeds are generally struck on the panel in the direction of the grain, and laid in on the panel across it, or along the ends; this is termed reed-flush.

Flush panels in inferior works have a single bead struck gh their sides in the direction of the grain alone, the ends abutting plainly, and this is termed, bead-butt, the fact that the panels are flush being inferred.

The plainest quality of framing, in which it is square on both sides, is used in the fittings of inferior bed-rooms, inner closets, and the plainer domestic offices, but always internally; framing moulded on one or both sides, in rooms and places of a greater degree of importance, and in places where the work may be more generally seen; in some cases a flat panel may be enriched by a small moulding laid on its surface, leaving a margin between it and the larger moulding at its extremities. This may be done in drawingrooms and apartments of that class, especially if they be in an upper story; and raised panels should be confined to the framed fittings of dining-rooms and other apartments on a ground or principal story. Framing with flush panels is almost restricted to external doors, &c., one side of a door being bead-flush, and the other flat and moulded, perhaps, or the face may be moulded with a raised panel, and the back bead-flush; and this for principal entrances. Bead-butt framing is found in external doors to offices, &c. Partitions between rooms are often made of framing as above described. Lately some sliding partitions have been put forward, one of which consists of two or three large sliding framings, and felt is relied upon to render them sound, proof. This is by Stone; while that by Williams consists of a series of framings pivoted at top and bottom, and with the pivots running on grooves at top and bottom, so that the shutters may be formed into a pilaster-like mass at the side of the room.

It is of the utmost'importance in framing that the tenons and mortises should be truly made. After a mortise has been made with the mortise chisel, it should be rendered perfectly even with a float,—an instrument which differs from a single cut or float file only by having larger teeth. An inexperienced workman often makes his work fit too tight in one place, and too easy in another, hence the mortise is split by driving the parts together, and the work is never firm; whereas if the tenon fill the mortise equally, without using any considerable force in driving the work together, it is found to be firm and sound. The thickness of tenons should be about one-fourth of that of the framing, and the width of a tenon should never exceed about five times its thickness, otherwise, in wedging, the tenon will become bent, and bulge out the sides of the mortise. If the rail be wide, two mortises should be made, with a space of solid wood between; fig. 80 shows the tenons for a wide rail. If the tenon occurs at the end of a piece of framing, it must be set back a little, so as to allow sufficient solid wood to form a sound mortise; this is called a haunching (see e, fig. 81). In thick framing, the strength and firmness of the joint is much increased by putting a cross or feather tongue in on each side of the tenon; these tongues are about an inch in depth, and are easily put in with a plough proper for such purposes. The projected figure of the end of a rail, as in fig. 80, shows these tongues put in; in the style there are grooves ploughed to receive them. Sometimes these projections are left in the solid wood itself, in which case they are called stump tenons. Sometimes, in thick framing, a double tenon in the thickness is made; but we give the preference to a single one, when tongues are put in the shoulders, as we have described; because a strong tenon is better than two weak ones, and there is less difficulty in fitting one than two. The panels of framing should be made to fill the grooves, so as not to rattle, and yet to allow the panels to shrink without splitting. When the mouldings are stuck on the framing, as is often the case in large stuff, it becomes necessary to find the lines to bring the angles together. In square framing, this is done simply by cutting ab,cd, as in fig. 81, at a mitre; but if the framing be oblique angle, it is done by scribing; the angle at a b being determined by the eye, cd is cut parallel to it. Where large projecting or bolection mouldings are used, the French have a very excellent way of framing (fig. 82), which it would be well to imitate in this country. Here C is the panel round which the moulding B is framed and mitred, the whole is then framed into A, which is a section both of the styles and rails. When a frame consists of curved pieces they are often joined by means of pieces of hard wood called keys. Fig 83 is the head of a Gothic window frame joined with a key, with a plan of the joint below it. A cross tongue is put in on each side of the key, and the joint is tightened by means of the wedges, a, a. It is, however, a better method to join such pieces by means of a screw bolt instead of a key, the cross tongues being used whichever method is adopted. Where the ends of the bolts cannot be allowed to project, they should be fixed as bed bolts. JDoors are made two and four panelled for the most part when the panels are flat and the framing square, six-panelled when the latter is moulded, and six, eight (as figs. 2 and 3, flate XXVI., to which the details in the following description will apply), or even ten-panelled when the framing is of the superior descriptions. Doors which are hung in two equal widths to occupy the doorway, and are hung to the opposite side posts or jambs of the frame, are said to be folding-doors or double-margined,—that is, the styles or margins are repeated necessarily in the middle where they meet. The style, muntin, and rails to doors are the same as in framing or wainscoting; and the panels may be moulded in the same manner. Doorways are fitted with jamb linings, and architraves or pilasters. Jamb linings, as A in fig. 86, when they exceed 9 or 10 inches in width, should always be so framed to correspond with the door on the outer faces; or they may be made solid. Narrow and plain jamb linings to inferior rooms are rebated on one side of the lining only, and the rebate forms the frame into which the door is fitted. To superior work they are rebated on both sides, as if it were intended to put a door on each side. The jambs are fixed to the inner edges of the grounds, which are’fixed to the wall to receive the architrave or other decorations to the opening, and to stop the plastering; if they are wide, and not framed, backings are put across to stiffen them; and these backings are dovetailed into the edges of the grounds.

It requires a considerable degree of care to hang a door, a shutter, or any other piece of work in the best manner. In the hinge, the pin should be perfectly straight, and truly cylindrical, and the parts accurately fitted together. The hinges should be placed so that their axes may be in the same straight line, as any defect in this respect will produce a considerable strain upon the hinges every time the hanging part is moved, will prevent it from moving freely, and is injurious to the hinges. In hanging doors, centres are often used instead ,of hinges; but, on account of the small quantity of friction in centres, a door moves too easily, so that a slight draught of air accelerates it so much in falling to, that it shakes the building, and is disagreeable. This may be in some degree remedied by placing a small spring to receive the shock of the door.

The greatest difficulty, in hanging doors, is to make them to clear a carpet, and be close at the bottom w hen shut. To do this, that part of the floor which is under the door when shut, or the width of the jambs, may have a piece of wood about a quarter of an inch thick above the general level of the floor, which, with placing the hinges so as to cause the door to rise as it opens, will be sufficient unless the carpet should be a very thick one. Several mechanical contrivances have been used for either raising the door, or adding a part to spring close to a floor as the door shuts. The best method now in use, and the simplest, is the invention of the rising or skew-butt hinge. The parts of this which bear on each other are made with a double bevel, so that, if more than half opened, the door falls against the wall by its own weight; if less than half open, it closes itself.

Various kinds of hinges are in use. Sometimes they are concealed, as in the kinds of joints called rule joints; others project, and are intended to let a door fold back over projecting mouldings, as on pulpit doors and outside folding shutters. When hinges project, the weight of the door acts with an increased leverage upon them, and they soon get out of order, unless they be strong and well fixed. The door of a room should be hung so that, in opening the door, the interior of the room cannot be seen through the joint. This may be done by making the joint according to fig. 84. The bead should be continued round the door, and a common butt-hinge answers for it

The proper bevel for the edge of a door or sash may be found by drawing a line from the centre of motion C (fig. 85) to e, the interior angle of the rebate; e d drawn perpendicular to C e gives the bevel required. In practice the bevel is usually made less, leaving an open space in the joint when the door is shut; this is done on account of the interior angle of the rebate often being filled with paint.

The extension of the principle of ploughing and tonguing work together is one of the most important of the improvements that have been introduced by modern joiners. It is an easy, simple, and effectual method of combination, and one that provides against the greatest defect of timber-work, its shrinkage. By means of this method, the bold mouldings of mediaeval architecture can be executed with a comparatively small quantity of material; and even in the mouldings of modern architecture it saves much labour. For example, the moulded part of an architrave may be joined with the plain part, as shown by fig.

86. . If this method be compared with the old method of glueing one piece upon another, its advantage will be more evident

Architraves and pilasters are variously sunk and moulded according to the fancy of the designer. They are fixed to the grounds with their internal edges exactly fitting to the rebates in the jambs, and they form the enriched margin or moulding of the frame in which the door is set. Architraves are mitred at the upper angle, but pilasters have generally a console or an enriched block or cap resting on them, to which they fit with a square joint; both the one and the other either run down and are scribed to the floor, or rest on squared blocks or bases, -which may be the height of the skirting board, or of the whole base.

The architraves, skirtings, and surbase mouldings, are fixed to pieces of wood called grounds, as A, fig. 86; and as the straightness and accuracy of these mouldings depend upon the care that has been taken to fix the grounds truly, it will appear that fixing grounds, which is a part often left to inferior workmen, in reality requires skill and attention; besides, they are almost always the guide for the plasterer. Where the plasterer’s work joins the grounds, they should have a small groove ploughed in the edge to form a key for the plaster. In old work the ground was generally hidden, but in modern work it is frequently shown, which is a saving of stuff; thus, instead of architraves being prepared as in fig. 86, they are made as shown in fig. 87, whero A is the rebated and beaded door-jamb, and B the ground, which is generally splayed at the back as a key to the plastering instead of being grooved. On this a thin piece of stuff is bradded to form the double-faced architrave, instead of sinking out of the solid, and on this the ogee or ovolo moulding is nailed. Again with base mouldings, A (fig. 88) is the ground fixed against the wall, on the top of which is nailed the upper moulding B, and C shows the skirting and lower moulding, fixed against a fillet on the floor.

We have thus far spoken chiefly of joinery as performed at the bench; but by far the most important part remains to be considered; for, however well a piece of work may have been prepared, if it be not properly fixed, it cannot fulfil its intended purpose. As in the preceding part, the general principles will be stated that ought to be made the basis of practice; and these illustrated by particular examples. When the carcass of a building is ready for the joiner, the first thing to be done is to cut the bond timber out of the openings, set the sash frames, and fill them with old sashes or with oiled paper on frames, to exclude the weather, but admit light. The flooring joists are then proved with straight-edges, and any inequalities in them are removed with the adze; the flooring boards are next cut down to their places, and are turned -with their faces downwards until the ceilings are done. First, however, the pugging is done, if any be intended. This is to prevent sound passing through the floor when finished, and is sometimes called deafening sound-boarding. It is effected by nailing fillets to each side of the joists, near the bottom, and laying on these pieces of rough boards across and close together; then there is put a layer of mortar mixed with chopped straw, or sometimes clay, sawdust, or small shells.

The preparation given to flooring boards in superior work is planing the face, shooting the edges, and gauging to a thickness,—the common fillister or stop rebate plane being used to work down to the gauge mark, from the back of every board, and about half an inch in on each edge. When a board is to be laid, it is turned on its face in the place it is to occupy, and the workman with his adze cuts away from the back over every joist down to the gauge rebate, so that on being turned over it falls exactly into its place, and takes the same level with all its fellows, which have been brought to the same gauge; then follows the process of laying, and the result must, if the work be done well, be a perfectly even and level surface. The slight inequalities of surface which may occur are reduced with a smoothing-plane, the brads being previously punched below the surface if the floor be face-nailed. Floors are in ordinary cases either laid straight joint or folding, and are edge-nailed, as fig. 89, or face-nailed. According to the folding method, two boards are laid, their heading joints all on the same joist, and of course in the same straight line, and nailed at such a distance apart that the space is a little less than the aggregate width of the three, four, or five boards intended for it; these boards are then put to their places, and, on account of the narrowness of the space left for them, they rise like an arch between its abutments. The workmen force them down by jumping upon them. Accordingly, the boards are never soundly fixed to the joists, nor can the floor be laid with any kind of evenness or accuracy. This method should be avoided in all good work. Straight joint flooring is when every board is laid separately, or one at a time, the heading joint or joints being broken or covered regularly in every case. Dowelling is the drivingpins of wood or iron half their length, into the edge of the last laid board, the outer edge of which has been skew-nailed, their other ends running into holes prepared for them in the inner edge of the next board, in the way the head of a cask is held together, and then its outer edge is skew-nailed in the same manner, and so on. Tonguing is effected by grooving both edges of every board, and fitting thin slips and tongues into them. The boards are usually forced together by pressure as with a clamp applied to the outer edge. The nail used in face-nailing floors is called a flooring brad; it has no head, but a mere tongue projecting on one side of the top of the nail, which is put in the direction of the grain, that it may admit of being punched in below the surface level, otherwise the superficial inequalities could not be reduced when the floor was completed, because of the projecting heads of the nails. For side or edge nailing, however, clasp-nails, nails whose heads extend across on two of the opposite sides, are used.

As boards can seldom be got long enough to do without, joints, it is usual, except in very inferior work, to join the ends with a tongued joint, as shown in fig. 89, where B is the joint. The etched board is first laid, and edge-nailed to the joist. In oak floors the ends are forked together sometimes, as shown at A (fig. 90), in order to render the joints less conspicuous. The joints should be kept as distant from one another as possible.

In laying floors the advice of Evelyn only to tank the boards down the first year, and nail them down for good the next, is certainly the best method when it is convenient to adopt it; but, as this is very seldom the case, we must expect the joints to open more or less as the wood lias been more or less seasoned. Now, these joints always admit a considerable current of cold air; and also, in an upper room, unless there be a counter floor, or pugging, the ceiling below may be spoiled by spilling water, or even by washing the floor. To avoid these disagreeable results, the boards should be ploughed and a tongue inserted into each joint, according to the old practice. When the boards are narrow, they might be laid without any appearance of nails, in the same way as a dowelled floor is laid, the tongue serving the same purpose as the dowels. In this case the cross or feather tongues for the joints should be used. A new system of flooring has for some years been used in London, to which the name of “Victoria floors” has been given. A rough floor of boards, three-quarters of an inch thick, is first laid, and the rest of the joiners’ work fixed, and the plastering finished. When all is done, a floor formed of inch or inch and quarter plank, ripped down the middle, and consequently very little more than 5 inches wide, is laid; the rough boarding being first covered with a layer of shavings, or old newspapers, or other waste paper. These boards are dowelled on one edge and nailed on the other, and a very sound floor is thus formed, which neither springs nor creaks. A wainscot floor can be laid well on this principle.

Another early operation in joinery is the fixing of the framed grounds for the doors and windows, and for the skirting (Plate XXVI. fig. 5, and woodcuts, figs. 86, 87, and 88) to which the plasterers may float their work. The skirting grounds are generally dovetailed at the angles, and are well blocked out, so that they may not vibrate on being struck, or yield to pressure when the plasterer’s straight-edge passes roughly over the surface; they must also be set with the utmost truth and precision. When the floors are cut down and the grounds fixed, the joiner’s operations in a building should be suspended until the plasterers have finished, or nearly so, and then the floors may be laid. By deferring this operation until that period, the workmen of the two different trades are prevented from interrupting each other, and indeed injuring each other’s work; and joiners always find employment in the shop preparing, as before intimated.

If the part to be fixed consists of boards jointed together, but not framed, it should be fixed so that it may shrink or swell without splitting or winding. The nature of the work will generally determine how this may be effected. Let us suppose that a plain back of a window is to be fixed. Fig. 91 is a section showing B the back of the window, A the windowsill, D the floor, C the skirting, and E the wall of the house. The back is supposed to be prepared as previously stated, and is kept straight by a dovetailed key a. Now, let the back be firmly nailed to the window-sill A, and let a narrow piece d, with a groove and cross tongue in its upper edge, be fixed to bond timbers or plugs in the wall, the tongue being inserted also into a corresponding groove in the lower edge of the back B. It is obvious, that the tongue being loose, the back B may contract or expand, as a panel in a frame.

In getting out skirtings, if the work be of a superior description, the boards should be tried up as for framing in every way except bringing to a width, which need not be done. The face edges, however, must be worked with great precision, and moulded or rebated as the case may require. Rebating or tonguing will be perhaps necessary when the skirting consists of more than one piece, that the different pieces may be made to fit neatly and firmly together; and all but the lowest piece must of necessity be brought to a width, as well as tried up in other particulars. A skirting in a single width is called by that term; but when it is made up of more than one part it is designated a base; the lowest board is then called the skirting board, and the upper the base moulding or mouldings (Plate XXVI. figs. 1 and 5). The skirting board is not brought to a width because the labour would be lost according to the ordinary mode of fixing it. The board is applied to its place with its lower edge touching the floor; but as the most perfectly wrought floors are found to have some slight unevenness of surface so close to the wall, a straight edge would not fit closely down to it in every part. The board is therefore propped up at one end or the other until the upper or faced edge is perfectly parallel with the average line of the floor, or rather so as to be perfectly level. A pair of strong compasses, such as are used by the carpenter, is taken, and opened to the greatest distance the lower edge of the skirting board is from the floor throughout its length; the outer edge near the point of one leg of the compasses is then drawn along the floor, whilst the point of the other, being kept vertically above it, is pressed against the face of the board, on which it marks a line exactly parallel to the surface of the floor, indicating, of course, every, even the slightest, irregularity there may be in it. If the floor be not a very uneven one, the excluded part may be ripped off with the hand or the panel saw, which may generally be made to follow the traced or inscribed line exactly; if, however, the line be a very irregular one, having quick turns in it, the hatchet must be used. This operation is called scribing, and the result of it is evidently to make the skirting fit down on the floor with the utmost precision. Care must be taken in performing the operation that the upper edges of the skirtings be not only level, but that all which are in immediate connection be scribed to the same height, that their upper edges may exactly correspond.

In the principal rooms of a house, the skirting C (fig. 91) is usually grooved into the floor D, and fixed only to the narrow piece d, called a ground. (See also Plate XXVI. fig. 5.) By fixing in this manner, the skirting covers the joint, which would otherwise soon be open by the shrinking of the back, and from the skirting being grooved into the floor, but not fastened to it, there cannot be an open joint between the skirting and floor. When it is considered that an open, joint in such a situation must become a receptacle for dust and a harbour for insects, the importance of adopting this method of fixing a skirting will be apparent. As grooving a floor is attended with considerable labour, and as the boards will sometimes twist, it is more common now to nail a small fillet to the floor, against which the back of the skirting rests, and, of course, has full room for expansion. Before skirtings are fixed, vertical blocks are put at short intervals, extending from the floor to the narrow grounds, and made exactly flush with and true to the latter, and are firmly nailed. These form a sound backing, to which the skirtings may be bradded or nailed, and so prevented from warping or bending in any manner. If, however, the skirting be not very wide, and be sufficiently stout to stand without a backing, a fillet only is nailed along the floor as a stop for its lower edge; but this is rendered unnecessary if the skirting be tongued into the floor, as the tongue will answer every purpose of a stop (fig. 5, Plate XXVI.) The ends of skirtings should be tongued into each other when it is necessary to piece them in length; and on returns or angles the end of one should be tongued into the returned face of the other in the square parts, and mitred in the oblique-angled or moulded parts.

The dado of a room should be fixed in the same manner as explained above for window backs (fig. 91). When a chair-rail or surbase is required, grounds similar to those for the base are fixed to range like them with the face of the plastering; the surbase itself must be wide enough to cover the grounds and the joints formed by them and the plastering completely; it is in effect a cornice to the stereobate (or pedestal, as the three parts may be termed of base, dado, and surbase), and the space or dado between it and the base is generally understood to be wainscoted, though it is more frequently plastered.

In fixing any board above 5 or 6 inches wide, similar precautions are necessary as those detailed in fig. 91, otherwise it is certain to split when the house becomes inhabited. We may, in general, either fix one edge and groove the other, so as to leave it at liberty, or fix it in the middle and leave both edges at liberty. Sometimes a wide board, or a piece consisting of several boards, may be fixed by means of buttons screwed to the back, which turn into grooves in the framing, bearers, or joists, to which it is to be fixed. If any shrinking takes place the buttons slide in the grooves. In this manner the landings of stairs are fixed, and it is much the best mode of fixing the top of a table to its frame.

The parts of the outside frame of a sash are distinguished by the terms applied to the similar parts of common framing. The upright sides are styles, and the transverse or horizontal ones, which are tenoned into the ends of the styles, are rails; but the inner framework or divisions for the panes are called merely upright and cross bars (these bars, according to the way they are moulded, are called lamb’s tongue, ovolo, beaded, &c.),—the upright being the mortised, and the cross bars the tenoned, as with the outer framework (Plate XXVI. fig. 1). Sashes are got out like common framing; the parts are tried up, set out, and mortised and tenoned, exactly in the same manner, allowance being made in the length of the rails and all tenoned pieces in the setting out, as in common framing also,for the portions of the mortised styles and upright bars which are worked away in forming the moulding and rebate. The meeting rails of sashes which are in pairs, to be hung with lines, are made thicker than the other parts by the thickness of the parting bead, and they are bevelled or splayed off, the one from above and the other from below, that they may meet and fit closely. When the framework is completed, although it cannot be put together because of what has just been referred to, the rebate is formed by the sash fillister on the further part of the face edge, and the moulding struck on its hither angle. These things being done, the moulded edges are either mitred or scribed at the shoulders and haunches, and the sash may be put together. If sash bars are mitred at the joints, they require dowels in the cross bars to act as tenons; but if they can be scribed, dowelling is not necessary. Sashes are either hung upon hinges or hung with lines, pulleys, and weights. Fixed sashes are put into frames, of which every part may be solid but the stop, which must be put in behind the sash to detain it. Sashes hung with hinges are usually called casements, and require solid rebated frames; but there can be no stops to them, except their own movable fastenings, and the outer stop, which of course the rebate furnishes. These are usually known as French casements, or sash doors, as they are called when they open down to the ground or floor; they have now taken the place of sash windows, where they may lead from the room to garden paving, or to a balcony, or may be used for similar purposes. The ordinary arrangement for an aperture is that of two leaves working on hinges at the sides inwards or outwards, meeting in the centre of the opening. With the former, which is the usual mode, one leaf is secured to the head and sill by bolts either round or sunk in; the other leaf, when closed, is secured to the first by a handle fixed on the second and turning over a staple fixed on the first. If the casement should be a high one, this second leaf often requires a bolt at top and bottom, to secure it against the force of the wind, which by bending it admits the cold air and wet. When it is placed towards an exposed aspect, and is thus subject to driving rains, it is necessary to take many precautions for the prevention of wet being blown through the meeting surfaces all round the casements. To effect this object, the styles, rails, and frames are sunk and beaded in various ways. Figs. 92 and 93 represent sills and bottom rails; and fig. 94, meeting rail, styles, and frame, which last is an ordinary arrangement in France. An improvement to the mere handle for securing the leaf of the casement is that of affixing an upright metal rod, which is turned by the handle C, fig. 92, on the leaf being closed, and by hooks at top and bottom as B, fig. 95, catching into a plate fixed for them, and effectually fastening it. A simpler method has been shown where, in lieu of the rod, a reeded bar, as D, fig 96, is moved to and fro as the leaf is required to be opened or shut, the top and bottom of the bar being rounded as shown at E, fig. 97, so as to slide into two segmental plates F, secured to the sill and lintel. Fig. 96 is a plan of the two casements, and 97 a plan of the head and sill. The metal rod, which is of brass, is called the Espagnolette bolt. Another mode of securing the casements has lately been introduced, whereby a flat plate, the whole height of the opening, is inserted in a groove formed in one edge of the meeting style of a leaf; and on this being closed the plate is shot forward by a handle into a groove in the other leaf, fastening the two together, the plate forming a stop against both the wind and the rain. This is a patent arrangement of Arch. Smith and Co. Fig. 98 is a plan of the usual French casement used at Paris. A shows the two leaves of the casement when shut; B is a plan of the shutters in their boxing, CC the shutters when closed, D the bolt, E the inside architrave and F the Persiennes, or outside blinds, shut against the stone reveals, and so provided for by the architect, instead of being an addition made by the upholsterer after the work is done, and perhaps spoiling the design. The ordinary mode is for them to be hung with projecting hinges to admit of their being folded back into the face of the wall, which is a hideous arrangement for any façade, except perhaps one of plain brickwork or plain cement. GG shows the position of the blinds when shut, and H is the outside architrave. Much difficulty arises in preventing the rain and wind from penetrating under sUclι doors. The French raise the doors very much to secure this, as shown in figs. 92 and 94. In England various methods have been adopted by forming second sills of metal cast into shapes to form gutters and throats; perhaps the best arrangement is the “patent sill or water bar” (fig. 99), as now manufactured by

Archibald Smith and Co. A metal plate A is screwed to the face of the bottom rail. An arrangement in metal B is screwed to the upper weathering of the wood sill C, having on its outer edge a plate D hinged to it. When the door is opened this plate falls down, and when the door or leaf is shut, a pin E, let into the underside of the bottom rail, forces up the hinged plate D, and presses it against the first named plate A, making all tight. Fig. 100 is a section of a mediaeval moulded bottom rail found in France. When the window lights are carried up over the casements, as is very often the case, the upper lights are generally fixed; but it is better that one or two of them should be rendered available for ventilating the apartment when it is not desirable to have the door itself open. This will be effected by hinging the light on the bottom rail, with the necessary means of opening and closing it, or placing it on centre hinges at the sides.

Sashes hung with lines require cased frames (Plate XXVI. figs. 1, 4), to receive the pulleys and weights. The sill of the frame is made, as in the former cases, solid, is sunk and weathered, and is generally made of a more durable material than the rest of the frame; the sides in the direction of the thickness of the frame are of one and a quarter or one and a half inch board, very truly tried up, and grooved to receive a parting bead; for it must be obvious that sashes hung with lines to run vertically up and down within the height of the frame must be themselves in two heights, and must pass each other in separate and distinct channels. The ends of these boards are fixed into the upper face of the solid sill below, and into a similar board parallel to the sill which forms a head above, and they are called pulley pieces, or styles, because they receive the pulleys, which are let into them near their upper ends.

Linings from 4 to 6 inches in width, and from three-fourths of an inch to an inch in thickness, are nailed on to the edges of the pulley pieces, and to the sill and head above and below, inside and outside, in the direction of the breadth of the sash frame, and are returned along the head in the direction of its length. The outside linings are made to extend within the pulley pieces about half an inch, to form a stop for the upper and outer sash; and the inside linings are made exactly flush with their inner faces. The casing is completed by fixing thin linings on the outer edges of the outside and inside linings, parallel to the pulley pieces, to prevent anything from impeding the weights. Thin slips called parting-beads are fitted tightly into the grooves previously noticed in the pulley pieces, but they are not fixed, as the upper sash can be put in or taken out only by the temporary removal of the parting-bead. An inner or stop bead is mitred round on the inside to complete the groove or channel for the lower sash; the stop bead covers the edge of the inside linings on the sides and head, and is fixed by means of screws, which may be removed without violence when it is required to put in or take out the sashes. A hole covered with a movable piece large enough to allow the lead or iron weight to pass in and out, is made in each of the pulley pieces, so that the sashes may be hung after the frames are set, and to repair any accident that may occur to the hangings in after use (Plate XXVI. fig. 4). It may be remarked that sash frames require greater truth and precision from the workman than anything else in the joiners’ work of a building; and unless the stuff employed be quite sound and perfectly seasoned all the workman’s care will be thrown away.

Sashes, it may be remarked, are never fitted until these frames are immovably fixed, so that if there be any inaccuracy in the latter, the sashes are cut away or pieced out to make them fit; but, as they are intended to traverse, the fitting in that case can only apply to one particular position, and in every one but that there must be something wrong. Any incorrectness in the sash-frame, again, must throw the shutters and their back flaps out; indeed, the sash-frame, though apparently a secondary part of the arrangement, is that which affe< Is all the rest beyond anything else. When sashes have been fitted, a plough groove, wide and deep enough to receive the sash-line, is made in the outer edges of the styles, for about two-thirds of their length, at their upper ends. They are then primed and glazed, and when the putty is sufficiently set the joiner hangs them. He is furnished with sash-line, which is made of the best flax well plaited together, tacks, and iron or lead weights, which are generally made cylindrical, with a ring at one end, to which the line may be attached. A sash is weighed, and two weights are selected which together amount to within a few ounces of a counterpoise. The line is then passed through the pulley, which was previously fixed in the pulley style; the end is knotted to a weight which is passed in at the hole left for the purpose; and at a sufficient distance, which a common degree of intelligence will readily determine, the line is cut off and the end tacked into the groove in the style of the sash. Other modes of attaching the sash-line to the sash are also used.

Of recent inventions connected with windows there are some for enabling the parting-beads to be taken out, or are dispensed with, so that sashes may be readily cleaned without the operator standing on the sill, a dangerous practice, and without the use of the glazier’s horse, which tends to injure the inside painting. A contrivance for easily opening and closing sashes of large size by an arrangement of cords and pulleys, which likewise secure it when shut, is patented by Mr Meakin. Another, having counterbalancing rack slips for hanging sashes, dispenses with the use of sash lines, pulleys, and sash weights. An objection to this invention may be that both upper and lower sashes must be opened at the same time. There are other useful arrangements for opening windows, such as those used in the wards of hospitals, where the opening is divided into about four horizontal lights working on pivots, all opening to any required extent by a rack and pinion. A sash fastener with a second spring, which clips the projection on the lower sash when the fastening is closed, and another where the shape of the arm of the fastener is altered, both prevent the sash being opened from without by a knife, a common mode of forcing an entrance into buildings. Patent wrought windows, and patent wrought iron water-tight windows and frames suitable for churches, parsonage houses, <kc., are readily obtainable.

The fittings of a window which has boxed shutters consist of back linings, grounds, back elbows and soffit, together with shutters and back flaps, and architraves (or pilasters) round on the inside to form a moulded frame (figs. 1 and 4, Plate XXVI.) Back linings are generally framed with flush panels; they fit in between the inside lining of the sash frame and the framed ground, to both of which they are attached, and form the back of the boxing into which the shutters fall back. They are tongued into the inside lining by their inner edge, and on the outer edge the ground is nailed, and they are set at right angles to the sash-frame, or obtusely outwards, as the shutters may be splayed or not. The back is the continuation of the window fittings from the sash-sill to the floor on the inside; the elbows are its returns on both sides under the shutters, and the soffit is the piece of framing which extends from one side of the window to the other across the head, or from back lining to back lining. These are all framed to correspond with the shutters on the face; but, as they are fixed, their backs are left unwrought. Window shutters are framed in correspondence with the door and other framed work of the room to which they belong, in front, and generally with a flush panel behind; the back-flaps are in one or two separate breadths to each shutter, according to the width of the window and the depth of the recess; they are made lighter than the shutters themselves, and they should, when shut to, present faces exactly corresponding with those of the shutters, both . intèrnally and externally. The shutters are hung to the sash-frame with butt hinges, and the back flaps are hung to their outer styles with a hinge called a back-flap, from its use. The shutters and their back flaps are hung in one, two, or more heights, as may be found convenient. The moulded margin round the boxings of a window on the inner face are made to harmonize generally with the similar parts of the doors of the room or place to which it belongs. See other examples of shutters and their boxing in fig. 98. The fixing and hanging of window fittings or dressings are hardly less important, for the accuracy required, than the making and fixing of the sash-frame itself; the slightest infirmity or inaccuracy in any part will be likely to derange some essential operation.

To this old manner of forming shutters must be added the rolling shutters of Clark, Bunnett, Francis, Snoxell, and others. These can be fixed either at the top, bottom, or side of the window as convenient, and are made of wood, steel, iron, or of wood and iron, many of them requiring machinery to raise and to lower them. The advantages consist in the small space occupied, the great security obtained, and the rapidity and ease in opening and shutting them. They are, however, apt to stick, and some are noisy, but one is called the “noiseless self-coiling revolving steel shutter.” One variety consists in a sheet of well-tempered corrugated steel, which coils up on itself like a roll of paper; another is a self-acting wood revolving shutter, with hardened steel bands.

The construction of stairs is generally considered the highest department of the art of joinery. The principal object to be attended to is that the stairs should afford a safe and easy communication between floors at different levels. The strength of a stair ought to be apparent as well as real, in order that those who ascend it may feel conscious of safety. To make the communication safe, it should be guarded by a railing of proper height and strength; in order that it may be easy, the rise and width (or tread) of the steps should be regular and justly proportioned to each other, with convenient landings; there should be no winding steps, and the top of the rail should be of a convenient height for the hand. The first person that attempted to fix the relation between the height and width of a step, upon correct principles, was, we believe, Blondel, in his Cours d ’ Architecture. His formula is applicable to very large buildings, but not to ordinary dwellings. Mr Ashpitel, who investigated the subject at length, gives the following rules for buildings of seven different classes :— [table]

These dimensions give angles of ascent varying from 24 to 37°. Of course the projection of the nosing is not reckoned.

Hawksley’s patent treads for staircases to public thoroughfares are composed of iron frames, in which small blocks of wood, placed the end way of the grain, are so secured as to present to the foot a roughened surface. They appear to be durable, and to admit of easy renewal of the wood when worn or injured.

The forms of staircases are various, commencing with a straight flight, which should only be used to a low story. In towns, where space cannot be allowed for convenient forms, they are often made triangular, circular, or elliptical, with winding steps, or are made of a mixed form, with straight sides and circular ends. In large mansions, and in other situations where convenience and beauty are the chief objects of attention, winding steps are never introduced when it is possible to avoid them. Good stairs, therefore, require less geometrical skill than those of an inferior character. The best architectural effect is produced by rectangular staircases, with ornamented railing and newels. In Gothic structures scarcely any other kind can be adopted with propriety for a principal staircase. Modern architecture admits of greater latitude in this respect,—the end of the staircase being sometimes circular, and the hand-rail continued, beginning from either a scroll or a newel.

When a rectangular staircase has a continued rail, it is necessary that it should be curved so as to change gradually from a level to an inclined direction. This curvature is called the ramp of the rail. The plan of a staircase of this kind is represented by ABCD in fig. 101; and fig. 103 shows a section of it, supposing it to be cut through at ab, on the plan. The hand-rail is supposed to begin with a newel at the bottom, and the form of the cap of the newel ought to be determined so that it will mitre with the hand-rail. Let H in fig.

102 be the section of the hand-rail, and ab the radius of the newel; then the form of the cap may be traced at C. The sections of hand-rails are of various shapes; some of the most common ones are too small; a hand-rail should never be less than would require a square of which the side is 2⅜ inches to circumscribe it. For the level landings of a staircase the height of the top of the hand-rail should never be more than about 40 inches, and in any part of the inclined rail the height of its upper side above the middle of the width of the step should be 40 inches, less the rise of one step when measured in a vertical direction. To describe the ramps, let r s in fig. 103 be a vertical line drawn through the middle of the width of the step; set r u equal to r s, and draw u t at right angles with the back of the rail, cutting the horizontal line st in t ; then from the point t, as a centre, describe the curve of the rail. When there is a contrary flexure, as in the case before us, the method of describing the lesser curve is the same.

The hand-rail of a stair generally begins with a scroll, and the first step of the stair is generally finished with what is called a curtail, a form corresponding closely to the scrolL There are a great variety of geometrical spirals; but as they all finish on a point, and as all architectural scrolls and volutes finish on a circle or eye, the usual mathematical scrolls are inapplicable. The earliest spiral adapted to architecture was that of De Lorme. Since his time several systems have been invented, particularly that of Goldmann; the best is that derived from the Ionic volute (fig. 104).

The height, eye, and number of revolutions of the spiral being given to describe the curve, let AB be the total height, and AC the intended height of the eye, and let the spiral be required to make two revolutions. Divide BC into four times as many parts as there are revolutions required (4 × 2 = 8), because there are four quadrants in every revolution. Draw any line DE equal to the height of the spiral. Set down from D half the number of the parts and one more (4 + 1 = 5); this is the top of the eye. Set down half AC at O, and describe the eye; then at 0 set up half a part to F, and make FG, FH = OF; then, as in fig 105, draw OG, OH, GI, and from 0 draw a line parallel to GH, and divide the same into as many parts as there are to be revolutions. Fig. 105 is for one, and fig. 106 for two revolutions. Bisect 01 at X; make 21 = 2X, and join XI; and through 1 draw MN parallel to OF to meet OG and XI. Draw the quarter circles, as in the diagram,—HD being the first opening of the compasses, GP the next, and H, G, I, K j L, M, and N being the centres. To describe the scroll let AB, as in fig. 107, be the width across, usually about 10 or 12 inches; let EB be the intended diameter of the eye; and let the scroll be required to make one revolution and a half, or six quadrants (these are shown at greater size by the side of fig. 108), then proceed as last directed, and complete the scroll, also dot in the lines of the nosings and risers. For the curtail step transfer the lines of nosings a, and the lines of the risers b, to another place, as in fig. 108, and set out the thickness of the veneer within the line of nos ing, the part within this represents the solid block of the curtail. The places of the balusters are shown in fig. 107.

It is obvious that in every geometrical staircase, the half of a cylinder placed upright in the well-hole would touch the wreathed string in all parts, another a little less would touch all parts of the hand-rail. Let us suppose ACB, as in fig. 109, to be the plan of half a cylinder so set upright in the wellhole, and let us suppose A'E to be the height of the same. Divide the curved line ACB into any convenient number of parts, and set the same off by compasses on the straight line from C to A ’ and C to B'. Or, in case ACB is a semicircle, divide the line AB, draw the diameter CD, making αD equal to three-fourths of the radius, and draw DA, DB', and the rest of the lines through the points of division, as shown in the diagram. Then A'B' is the stretch out or length of the circumference ACB unrolled. But A'E is said to be the whole height. From E set down the respective heights of the winders, step by step, as shown. Now let G be the representation of the cylinder, with the different lines squared up and across, these will give a representation of the curve at which the winders must ascend, and which, of course, must regulate the hand-rail. The other faint lines show the edge of the covering.

Fig. 112 represents the plan of a staircase, beginning with a scroll, and having steps winding round the circular part of the well-hole. In the first place, let the end of the steps be developed according to the method we have just given (fig. 110 shows this development). Now the hand-rail ought to follow the inclination of a line drawn to touch the nosings of the steps, except where there is an abrupt transition from the rake of the winding to that of the other steps; at such places it must be curved,—the curve may be drawn by the help of intersecting lines, as in fig. 111. The part which is shaded in fig. 109 represents the handrail and ends of the steps when spread out, and the handrail is only drawn close to the steps for convenience, as it would require too much space to raise it to its proper position. This development of the rail is called the fallingmould. We will now refer to fig. 113, and will suppose the inner semicircle of ACB to be the plan of the wellhole, and eA, αB, the width of the rail; then the outer shaded part ACB will be the plan of the rail on the level; ADEB is the cylinder referred to before— ADE being the angle at which the stairs ascend.

Now since by the principles of Conic Sections the oblique section of a circular cylinder is an ellipse, if the cylinder be circular the lines may then be found by a trammel. Be it of what section it may, the delineation of a cylinder cut at any angle ADE may be found by dividing it into equal parts, and setting up the ordinates al, b2, <fcc., as shown. This delineation is a plan “on the oblique,” or the facemould of the rail, to be cut “on the plumb.”

The wood used for hand-rails being of an expensive kind, it becomes of some importance to consider how the plank may be cut so as to require the least quantity of material for the curved part of the rail. Now, if we were to suppose the rail executed, and a plain board laid upon the upper side of it, the board would touch the rail at three points; and a plank laid in the same position as the board would be that out of which the rail could be cut with the least waste of material. Let it be required to find the moulds for the part ab of the rail in fig. 112, and to avoid confusing the lines in the small figure, the part a b has been drawn to a larger scale in fig. 114. The plain board mentioned above would touch the rail at the points marked C and B in the plan; draw the line CB, and draw a line parallel to CB, so as to touch the curve at the point E. Then E is the other point on the plan; and e, and b', are the heights of these points in the development in fig. 110. Erect perpendiculars to CB, from the points C, E, and B (fig. 114), and set off Ca' in fig. 114 equal to de in fig. 110, Ee ’ equal to de', and Bδ' equal to fb'. Through the points C and E, draw the dotted line Ch ; through a', e', draw a line to meet CE in h; and through the points a', b', draw a line to meet CB in g ; then join hg, and make Cz perpendicular to hg. Now, if Cd be equal to Ca, and perpendicular to Ci, and d i be joined, it will be the angle which the plank makes with the horizontal plane, or plan. Therefore, draw FD parallel to Ci, and thence find the section, which is the same thing as would be obtained by projecting vertical lines from each point in the hand-rail against the surface of a board laid to touch it in three points. The inexperienced workman will be much assisted in applying the moulds if he acquires a clear notion of the position when executed.

To find the thickness of the plank, take the height to the under side of the rail cr in the development (fig. 110), and set it off from s, in the line Ci, to r, in fig. 114; from the point r draw a line parallel to d i, and the distance between those parallel lines will be the thickness of the plank. The mould (fig. 114), which is traced from the plan, is called the face mould. It is applied to the upper surface of the plank, which being marked, a bevel should be set to the angle i d C, and this bevel being applied to the edge will give the points to which the mould must be placed to mark out the under side. It is then to be sawn out, and wrought true to the mould. In applying the bevel, care should be taken to let its stock be parallel to the line d i, if the plank should not be sufficiently wide for d i to be its arris. In the method fig. 113, ADE, on the rise of the stair, is the bevel. After the rail is truly wrought to the face-mould, the falling-mould (fig. 110), being applied to its convex side, will give the edge of the upper surface, and the surface itself will be formed by squaring from the convex side, holding the stock of the square always so that it would be vertical if the rail were in its proper situation. The lower surface is to be parallel to the upper one. The sudden change of the width of the ends of the steps causes the soffit line to have â broken or irregular appearance; to avoid this, the steps are made to begin to wind before the curved part begins. Different methods of proportioning the ends of the steps are given by Nicholson, Roubo, Rondelet, and Krafft. We cannot in this place enter into a detail of these methods, nor can we give the varied systems of cutting the rail in the spring and in the plumb, about which so much has been written, but for the reader’s information a list of the principal writers on Staircases and Hand-Railing is subjoined.

Nothingappearstohave been written on joineryuntil Joseph Moxon, a fellow of the Royal Society, published a work entitled Mcchanick Exercises, or the Doctrine of Handy works, 4to, 1677. The introduction of the geometrical staircase, or stair supported on one side by the wall, invented, says Palladio, by the famous Luigi Cornaro (the first English example of which is said to be that erected in stone by Sir Christopher Wren in St Paul’s Cathedral), led to the greatest changes in the art of joinery, inasmuch as the lines for setting them out necessitated a very considerable knowledge of geometry. The hand-rails of these stairs offered most difficulties, and an imperfect attempt to remove them was first made by Halfpenny, in his Art of Sound Building, published in 1725. Price, the author of the British Carpenter, published in 1733-35, was more successful, and his remarks show a considerable degree of knowledge of the true nature and object of his researches. The publication of this book must have produced a considerable sensation in the trade, for it was soon followed by many other works of different degrees of merit. Of these the publications of Langley and of Pain were the most popular, and were followed by Roubo, L'Art de Menuisier, folio, 1771; Skaife, Key to Civil Architecture, 8vo, 1774; Transactions of the Society of Arts, &c., for 1814; Treatise on the Construction of Staircases and Hand-Rails, 4to, 1820; Rondelet, Traité de l'Art de bâtir, tom. iv. 4to, 1814; Krafft, Traité sur l'Art de la Charpentier, part ii., folio, 1820; Jeakes, Orthogonal System oj Hand-Railing, 1849; Ashpitel, On Hand-Rails and Staircases, 4to, 1851; Galpin, Joiner's Instructor, Staircasing and Hand-Railing, 4to, 1853; and Riddell, Hand-Railing Simplified, folio, Philadelphia, 1856 and 1860.

The establishment of the principles of joinery on the sound basis of geometrical science was reserved for Nicholson. In his Carpenter's New Guide and Carpenter and Joiner's Assistant, published in 1792, 4to, he has made some most valuable corrections and additions to the labours of his predecessors. This writer has been the founder of all the subsequent works on the subject; his books have been published again and again, in various forms, with additions from time to time, by different hands, as Galpin’s Joiner's Own Book, showing Improvements since the Days of the late Mr Nicholson, 4to, 1856. Corresponding improvements were also made in the practice of joinery, for which we are much indebted to an architect, Mr James Wyatt.

For revived mediaeval and Elizabethan joinery, particularly as adapted to windows and staircases, see Weale ’ s Carpentry, 4to, 1849, and Shaw, Details of Elizabethan Architecture, 4to, 1839. Many modern improvements are given in Laxton’s Examples of Building Construction, fol., 1855-58, and in Newland’s Carpenter and Joiner's Assistant, fol., Liverpool, 1860.

The principles of joinery were cultivated in France by a very different class of writers. The celebrated Blondel, an architect of great eminence, had given details for the construction of shutters, wainscoting, doors, hinges, fastenings, &c., in his work Distribution des Maisons de Plaisance, 4to, 1737-38. In the extensive work of Frezier, entitled Coupé des Pierres et des Bois, 3 vols. 4to, 1739, all the leading principles are given and explained with tedious minuteness, offering a striking contrast to the brevity of English writers. The first elementary work on that part of geometrical science which contains the principles of joinery appeared in France in 1705, from the pen of the celebrated Gaspard Monge, who gave it the name of Géométrie Descriptive. The most celebrated French work which treats of joinery is Rondelet’s L’Art de bâtir, which occupied fourteen years (from 1802 to 1816) in publication. It is also the best foreign work on the subject; but it is little adapted to the state of joinery in England. In practice the French joiners are very much inferior to the English workmen. Their work is rough, slovenly, and often clumsy, and at the best is confined to external effect. The neatness, soundness, and accuracy, which is common to every part of the works of an English joiner, is scarcely to be found in any part of the works of a French one. The little correspondence, in point of excellence, between their theory and practice leads us to think that their theoretical knowledge is confined to architects, engineers, &c., instead of being diffused among workmen, as it is in England. See also ThioUet et Roux, Nouveau Recueil de Menuiserie, 1837; Viollet-le-Duc, Diet. Raisonné du Mobilier Français, 8vo, 1858, &c.; and Nosban, Manuel de Menuiserie, 4to, 1849. Much also may be learned from Emy, Traité de la Charpente, foL, 1847—particularly with regard to fra ming. The publications of other nations do not call for particular notice.

Cabinet-making.

Cabinet-making, or that part of the art of working in wood which is applied to.furniture, has some affinity with joinery, the same materials and tools being employed ip both, and the mode of execution being the same. Correctness and strict uniformity are not so essential in movable, as in the fixed parts of buildings; they are also more under the dominion of fashion, and therefore are not so confined by rules as the parts of buildings. Cabinet-making offers considerable scope for taste in appropriate and beautiful forms, and also in the choice and arrangement of coloured woods. It requires considerable knowledge of perspective, and also that the artist should be able to sketch with freedom and precision. If the cabinet-maker intend to follow the higher departments of his art, it will be necessary to study the different styles of architecture, in order to make himself acquainted with their peculiarities, so as to impress his works with the same character as that of the rooms they are to furnish.

In cabinet-work the French workmen are certainly superior to the English, at least as far as regards external appearance; but when use as well as ornament is to be considered, the latter certainly carry away the palm. The appearance of French furniture is much indebted to a superior method of polishing, which is now generally known in England. The method of making and using French polish is minutely described in Dr Thomson’s Annals of Philosophy, vol. xi. pp. 119 and 371. For many purposes, however, copal varnish (such as coachmakers use) is preferable; it is more durable, and bears an excellent polish. Foreign oak is much used for cabinetwork; and lately, the fine curled oak that is got from excrescences produced by pollard and other old trees has been used with success in furniture. When well managed it is very beautiful, and makes a pleasing variety. It is relieved by inlaid borders of black or white wood, but these should be sparingly used. Borders of inlaid brass, with small black lines, give a rich effect to the darker coloured kinds, as in buhl-work. Cedar is occasionally used for small fittings, or for cupboards where woollens and furs are stored. Ebony and imitation ebony are useful for cases. Russian birch has of late years been largely in request for bedroom furniture from the cleanly appearance of it. But of all woods mahogany has maintained its place since the first introduction of it in the end of last century. The japanner is now seldom employed to give a colour to wood, as variety can be obtained by staining, heightened by varnishing; or the plain deal or pine is polished or varnished like mahogany or oak. Patterns or lines are stencilled or burnt in according to one or other of the many patents now before the public.

Many curious works on furniture were published in the reigns of Louis XIV. and XV.; those by Sir W. Chambers and the Adams also deserve attention. Cruden’s Joiner's and Cabinet-maker's Darling, 8vo, 1770, is a curious book. In ornamental composition much benefit may be derived from Tatham’s Etchings of Ancient Ornamental Architecture, London, 1799; Percier and Fontaine’s Recueil des décorations intérieures comprenant tout ce qui a rapport à I' Ameublement, Paris, 1812; and, for general information, Sheraton’s Cabinet Dictionary, 1803, and his Cabinet -ι naker and Upholsterer's Drawing-Book, 4to, 1793, may be referred to. Bridgen’s Designs for Furniture, fol. 1826, and Shaw’s Details of Elizabethan Architecture, 4to, 1839, are of much value. But the most important works that can be consulted at the present time are the various illustrated publications relative to the Great Exhibitions in London and Paris (1851, 1855, and 1862), where some of the finest specimens of carpentry in the world were exhibited. The most accessible to the English reader are the Art Journal and the Illustrated London News. Slater-work.

The slater works his material, slates, for the protection of a building by covering the roof timbers with it, in the same manner as a bricklayer works his tiles. Besides this, which is his chief business, he supplies sawn slates for shelving in larders and dairies, for tanks and cisterns, for pavements, steps, and landings, for panels of doors, for covering hips and ridges, and a few other purposes. Enamelled slate for chimney-pieces, lavatories, and similar applications is of great utility.

The slater’s principal tool is a large knife or chopper called a saixe, sax, or zax, with which, before he begins to work on a roof, he shapes and trims the slates on the ground, sitting on one end of a stool, which forms a sort of bench and has uprights by which to square the slate. With this knife he strikes off the unevenness on one side of a slate, making it as nearly straight as he can; he then runs a gauge along it, marking the greatest width the slate will bear, and, cutting to that line, makes it perfectly parallel. He next, with a square, brings the thickest and best end to right angles with the sides, generally by chopping, but sometimes by sawing; and then marking upward from the squared foot or tail, makes two nail holes, where, by calculating the gauge the slate in hand will bear, he knows the batten must come. He also uses a drag, which is a long flat piece of iron having a cutting edge at the top and hooked on each side; when he has to strip a roof, he forces it between the slates, and pushes out or cuts off the heads of the nails, and thus the slate is loosened. He has also a couple of knee pads to kneel upon while at work.

The best slate obtained in Britain is from the quarries of Bangor in Carnarvonshire. The Llangollen quarries are remarkable for the size of the slates that can be obtained. The Delabole quarries in Cornwall have been worked for a considerable period, and supply a grey blue slate. Good slate is also procured in the neighbourhood of Tavistock in Devonshire. An esteemed pale blue green slate is obtained from Kendal in Westmoreland. Cumberland sea green slates are shipped from Maryport. Whitland Abbey green slates are much in vogue. The Ballachulish quarries in the north of Scotland are extensive, and supply a good quality. In Ireland are several, of which the Valentia, co. Kerry; Killaloe, co. Tipperary; Benduff, co. Cork; and those in co. Wicklow, are the best.

The best slate is of a bluish-grey colour, which breaks before the zax like well-burnt pottery, and will ring in the same manner on being struck. Whitish or light greycoloured slate is for the most part stony; dark blue or blackish slate, on the other hand, cuts very freely, but it absorbs moisture and decays rapidly. The best slates have a hard and rough feel, whilst an open absorbent slate feels smooth and greasy.

Though slate is classed among the incombustible materials, it must not be depended upon for resisting fire, as unfortunately it will crack and fall to pieces at no very high temperature.

The scantlings of slate are cut in the quarries to set sizes, and these are split into tablets, thicker or thinner according to the size of the slab and the nature of the slate; for the inferior qualities are neither so compact in material, nor so clearly laminated or schistose, as the superior, and will not therefore rend so freely. The sizes of slates best known in the British market are distinguished by the names of ladies, countesses, duchesses, and queens. Ladies measure 15 inches by 8, countesses 20 inches by 10, duchesses 24 inches by 12, and queens 36 inches by 24, and they are valued in proportion to their magnitude. Besides these, there is a slate which equals the queen in extent of surface, but is of very much greater thickness; this is called Welsh rag. A smaller slate, again, which is less indeed than the lady, and is cut from the refuse of large scantlings, is called a double; in size it does not often exceed 12 inches by 6. Westmoreland slates are thick and heavy like the Welsh rag, but do not generally run so large.

The principle on which slates are laid is the same as that which is employed in plain tiling. To a roof with projecting eaves a wide board is placed over the ends of the rafters; but when the eaves tail into gutters, the gutter-board is made wide enough to receive the eaves-course For light slating it is necessary to board a roof all over with three-quarter inch rough boarding. This is done by the carpenter; but for strong heavy slates, fillets or laths or battens are considered sufficient; and these are laid by the slater himself, to suit the length of his slates. Three inches wide and one inch thick is a sufficient size for them, if the rafters be not more than 12 inches apart. Against gable or party-walls, a feather-edged board called a tilting fillet is laid to turn the water from the wall. A preferable plan, however, is to board all roofs; it gives a better bed for the slates, and fewer are broken if there be occasion for workmen to walk over them in repairing or in cleaning out the gutters. The expense, too, is but trifling beyond that of the laths. A still further benefit is obtained by bedding the slates in mortar or in hay, which fills up the spaces left by the thickness of the first slate, and with the boarding tends to keep the roof cooler in summer and warmer in winter, a very desirable result for the habitable rooms close under them. Where the roofs are finished with diagonal boarding on purlins without rafters, it makes a very sound bedding for slates. All the slates being gauged to a width, and dressed as above described, and sorted in lengths, they are then taken up to the roof in rotation, beginning with the longest and largest for the lowest courses. The first course the slater lays is little more than half the length of that which is intended to cover it, and is necessary to break the joints at the eaves. This is called the doubling eaves-course; and the covering eaves-course is brought to the same foot line, completely to cover it. Then to ascertain the gauge :— from the length of the slate deduct the bond, which should never be less than 2 inches, and need not be more than 3∣ inches, and the half of what remains will be the gauge. Thus, if the bond be fixed at 3 inches, and the slate is 2 feet 3 inches in length, the gauge will be 1 foot. This gauge or margin is set up from the foot of the eaves-course at each end, and a line strained to mark it along the whole length, and so on, to the ridge or top, where another half-course is required to complete the work, and that is in its turn secured by a covering of sheet lead with a roll. To a hipped roof care is taken to complete every course up to the angle, by cutting slates to fit its slope; and these are also covered by an overlap of sheet lead with a roll, it being nailed or screwed to the hip rafter, and the head bossed over.

Slate ridging with a roll, as fig. 115, or with a groove for receiving an ornamented cresting, is now very usual, and even a common ridge tiling is necessary to prevent theft of the lead in some localities. Fig. 11G shows specimens of the ornamental red ridging tiles occasionally used, continuously or some lengths of a plain tile apart. In fig. 115, A, A are the two portions of the slate roll ridging, B being the roll with a hole drilled at each end for the insertion of a piu to fix the lengths; C the ridge piece fixed in the head of the king-post D; E the rafter; F the lath on which G, the slating, is nailed. In nailing a slate, it must not be strained or bent in the slightest degree, or it will certainly fly in some sudden atmospheric change, to which it is of course constantly liable, even if it escape fracture from being trodden on by the workmen themselves or by others. Copper, being less liable to oxidize from exposure to common causes than any other metal that will answer the purpose, should always be used for slate nails. Zinc is also occasionally used; and iron tinned and painted nails are sometimes substituted by dishonesty on the part of the workman or builder, or bad economy on that of the proprietor. The French method of fixing slates by means of wire clips which hold the bottom of the slates is unusual in England. A method has lately been introduced of effecting it with lead clips, which is said to dispense with a certain proportion of slates. Each slate is held in something of the same manner which the slater now adopts when a broken slate has to be replaced, and the main advantage is supposed to be that the slates are firmer.

The mode above described of ascertaining the gauge or margin by the bond, is equally applicable to every sort of roof-covering that is made up of small inflexible parallelogramic slabs or tablets; and it should be borne in mind that the greater the angle is at which the rafters rise, or, in technical language, the higher the pitch of the roof, the less the bond may be, and vice versa. With slabs or tablets that vary in length, too, as slates generally do as they are brought to market, it is the bond which it is of importance to observe; but if they are of an invariable length, as tiles are, it is sufficient that the gauge or margin be attended to.

A very light and neat covering is produced by laying wide slates side by side, and covering their joints with narrow slips bedded in putty, the overlap at the ends being no more than the bond is with the usual mode. It is known as patent slating, and was introduced by Mr Wyatt, who never, however, obtained a patent for it. Indeed it is in principle the mode which was adopted in ancient Greece in covering the roofs of temples. Neither boards nor fillets are used, the slates bearing from rafter to rafter, which may be 2 feet or more apart, and to the rafters the slates are screwed. The covering slips are also screwed, as well as bedded in putty. Slating of this kind may be laid at no greater elevation than 10°, whereas for slating in the ordinary way the angle should never be much less than 25°, though large slates with a 3∣ inch bond, carefully laid and pointed, may perhaps be trusted at a rise of 20°. This mode of applying slate is not without the disadvantage attending the fixing of any substance that freely takes up and readily parts with heat. In expanding and contracting, the joints are too often destroyed, aud leaks are tho comm'on consequence.

Thatching is an admirable covering for securing warmth in winter and coolness in summer; but it is subject to injury by birds, and to risk from fire. It is still occasionally used in picturesque cottages, arbours, and similar buildings, and was much used for churches in Norfolk and Suffolk. The thatcher requires a common stable fork, to toss up the straw together before being made into bundles; a thatcher’s fork, to carry the straw from the heap up to the roof; a thatcher’s rake, to comb down the straw straight and smooth; a knife, or eaves knife, to cut and trim the straw to a straight line; a knife, to point the twigs; a half glove of leather, to protect the hand when driving in the smaller twigs or spars; a long flat needle; a pair of leather gaiters to come up above the knees, used when kneeling on the rafters; and a gritstone to sharpen the knives. Wheat straw lasts from 15 to 20 years, and oat straw about 8 years. Reed thatching, as done in the West of England, is the truss after the ears have been cut off, leaving the clean, sound pipe straw, of which a thickness of 3 inches is laid on the common thatching with spars only. The materials required are straw or reeds, laths, nails, withes, and rods. A load of straw, laid on about 12 to 16 inches in thickness, will do a square and a half; a bundle of oak laths, 1⅛ inches wide, and from to fths thick, nailed about 8 inches apart, 1 square; a hundred of withes, 3 squares; a pound of rope yarn, 1 square; a hundred of rods, 3 squares; and 2⅜ hundred of nails, 1 square. Probably thatched roofs were formerly ornamented by a species of cresting, for in some parts of the country the withes or willow twigs that bind the thatch are sometimes arranged on the tops of ricks and cottages in an interlacing manner, terminating at the apex or at each end with a spike with a rudely formed cock. Viollet-le-Duc, in his Dictionnaire, alludes to the custom of forming the ridge in mud, in which plants and grasses were inserted to prevent the earth being dissolved and washed away by the rain.

Plumber-work

Lead, as the name imports, is the material in and with which the plumber works. The principal operations of this trade are directed to the covering of roofs and flats, laying gutters, covering hips, ridges, and valleys, fixing water trunks, making cisterns and reservoirs, and laying on the requisite pipes and cocks to them, fixing water-closet apparatus, setting up pumps, and applying indeed all the hydraulic machinery required in economic building. The plumber’s tools are knives, chisels, and gouges for cutting and trimming, rasps or files and planes for fitting and jointing, a dressing and flatting tool for the purposes its name expresses, iron hammers and wooden mallets for driving and fixing, ladles in which to melt solder, grozing irons to assist in soldering, a hand-grate or stove which may be conveniently moved from place to place for melting solder and heating the grozing irons, a stock and bits for boring holes, and a rule of two feet in length divided into three parts, two of boxwood, the third of steel, for passing into places he may have to examine; also compasses, lines, and chalk for setting out and marking, and centre-bits of all sizes for making perforations, together with weighing apparatus, as the quantities of most of the materials used by the plumber must be either proved or determined by weight. The waste of lead in working is very trifling, as cuttings all go to the melting pot again with little or no loss but that of refounding or casting; and even old lead is taken by the lead merchant in exchange for new at a very trifling allowance for tare and the cost of reworking. A plumber is always attended by a labourer, who does the more laborious work of carrying the materials from place to place, helps to move them when necessary, melts the solder and heats the grozing irons, attends to hold the one or the other, as neither may be set down or put out of hand when in use, and assists in some of the minor and coarser operations.

In boarding roofs, flats, and gutters for lead, clasp-nails or flooring brads should be used; and the first care of the plumber should be to punch them all in from an eighth to a quarter of an inch below the surface, and stop the holes carefully and completely with putty, or a chemical process will ensue on the slightest access of moisture should the iron heads of the nails come in contact with the lead, and the latter will, in the course of no long period, be completely perforated over every one of them. Neither should lead in surfaces of any extent be soldered, or in any manner fastened at the edges, without being turned up so as to make sufficient allowance for the expansion and contraction which it is constantly undergoing during the various changes in the temperature of the atmosphere. It may be taken, indeed, as a general rule, that solder should be dispensed with as much as possible. Like glue to the joiner, it is indispensable in many cases; but like glue also, it is in common practice made to cover many defects, and much bad work, that ought not to exist. The soft solder used by plumbers on account of its melting easily is a composition of tin and lead in equal parts, fused together, and run into moulds in shape not unlike the bars of a gridiron. In the operation of soldering, the surfaces of the metal intended to be joined are scraped and rendered very clean; they are then brought close together, and sprinkled with resin or borax at the joints to prevent oxidation while soldering. The heated solder is then brought in a ladle and poured on the joint, and smoothed and finished by a hot grozing iron and rubbed down with a cloth.

Sheet lead, whether cast or milled, is supplied of various weight or thickness, and is always described as of such weight (4 to 12 pounds) to the superficial foot. There are very few purposes, indeed, in building, in which lead of less than 6 lb to the foot should be used, and very few in which the weight needs to exceed 10. For roofs, flats, and gutters, under ordinary circumstances, 7 or 8 ft> lead is a very fair and sufficient average; for hips and ridges, lead of 6 ft> to the foot is thick enough; and for flashings 5 ft> lead need not be objected to. Cast lead has been preferred for the former purposes, because its surface is harder, but milled lead is of more even thickness throughout, bends without cracking, which is not always the case with cast lead, and makes neater work. Sheets of cast lead run from 16 to 18 feet long and 6 feet wide; milled sheets are made of about the same width, and 6 or 8 feet longer than cast sheets. Neither the one nor the other may be safely used on flats, or in gutters exposed to the wide range of temperature of our climate, in pieces of more than half the length and half the breadth of a sheet; that is to say, from 8 to 12 feet long, and 3 feet wide, are the limits within which sheet lead will expand and contract without puckering and cracking; and to allow it to move freely it is laid with rolls and drips in such a manner that any extent of surface may be covered with the effect of continuity, though the pieces of lead forming the covering be of such small sizes as above stated. But all fixing, whether by soldering or otherwise, is to be carefully avoided. A roll is a piece of wood made about 2 inches thick and 2∣ inches wide, rounded on one edge, and fixed with that edge uppermost, so as to come 4 inches within half the width of a sheet, that the edges may be turned up and folded round and over it, being lapped by, or lapping the edge of the adjoining sheet (Plate XXVI. fig. 7). Lead sufficiently stout, dressed neatly and closely down to the boards under it, and over the rolls at its edges, will require no fastening of any kind, unless it be so light as to be movable by the wind. Bolls are used mostly in roofs and flats; drips principally in gutters, though they may bo required in long flats. The drip is formed in the first instance by the carpenter in laying the , gutter boards, according to an arrangement with the plumber. It is a difference made in the height of the gutter of from 1∣ inches to 3 inches, where one sheet terminates in length, and meets another in continuation. The end of the lower is turned up against the drip, and that of the upper is dressed down over it, so as effectually to prevent the water from driving up under it. Where the fall is not great, a piece should be cut out across the higher gutter board, so that the top of the under-lead may lie level with the board. Gutters should have a fall of at least an eighth of an inch to the foot, and in flats it should be rather more, for such a covering is only so called in contradistinction to the pitch of a roof; ends and sides which are against a wall should turn up against it from 5 to 7 inches, according to circumstances; and the turning up under the slates, tiles, or other roof covering, to a gutter, should be to the level of that against the wall at the least. The turning up against the wall should be covered by a flashing. This is a piece of lead let into one of the joints of the wall above the edge of the gutter lead, and dressed neatly down over it, to prevent water from getting in behind it (Plate XXVI. fig. 6). Parallel or box-gutters are necessary next parapets where a curb roof is formed, and are useful in valleys of small roofs where the depth for it can be obtained. Fig. 117 is a section of such a gutter next to a parapet wall, in which A is the wall plate; B the tiebeam of the roof; C a bearer for carrying one end of the gutter bearer D, the other end being tenoned into the pole plate K; E the gutter boards carried by its bearers; G the lead gutter, laid in somewhat of an oval shape by the small angle fillets, which are useful in preventing the lead being returned at a right angle, where it is sometimes cracked in laying; H the flashing; I the eaves’ board for raising the last row of slates, over which the lead is fixed; L the common rafter; M the slating; N the principal rafter forming part of the truss of the roof; O the saddleback coping of the wall, throated on both sides. Where thick walls could be obtained, it was usual to form this sort of gutter below the timbers of the roof, whereby they were kept dry, and damage from the overflowing of the gutter prevented. The same result is occasionally achieved by a cornice projecting more than usual, the gutter being formed on it in place of a real blocking course. If the gutters and flats are to be often walked upon, they should be protected by deal lattice work raised on fillets but not fixed. ' Snow falling down the slopes is prevented by this from stopping the gutters, and it also lessens the action of the sun upon the lead-work. Lead on ridges and hips and the top and sides of dormers, not being in sufficient masses to be secured by its own weight, must be fastened by nails bossed over.

In making cisterns and reservoirs, unless they be cast (and these are now disused), the sheets of lead must of necessity be joined by soldering; but the water they are intended to contain protects the lead from the frequent and sudden changes to which in other and more exposed situations it is exposed. The lead-work forms a lining to a wood case, which has grooved and tongued sides and a bottom. But cisterns are now commonly made of zinc, or of galvanized iron, or of slate; the last two do not require a casing, but may perhaps be enclosed in a closet. Service or water pipes to and from the cisterns, as also waste or overflow pipes, are also made of lead, and described by their bore, as ⅜ in., ⅜ in., inch, and so on. They are generally supported and attached to the wall by means of iron holdfasts. Iron water pipes are fixed where lead will probably be stolen. The opinion that some waters are injured by coming in contact with the lead of cisterns and pipes, has led to the formation of pipes of tin encased in lead. The water companies are now requiring a water regulator to be put to each closet, or a water waste preventor where the constant supply is obtained, but these are a very troublesome addition to the plumber’s work, on account of the difficulty of keeping them in working order. The constant supply system requires taps of a different construction from those used in other cases; these are called “screw down valves,” from their action, and resist the pressure of the water. As repairs must occasionally be needed to the main pipes, it is recommended that, to prevent inconvenience, one or more cisterns be always provided in the house for containing two days’ supply of water.

Rain-water trunks and pipes are made of a certain number of pounds weight to the yard in length, according to the bore or calibre that is required. The pipes are fitted with large case heads above, to receive the water from the gutter spouts, and with shoes to deliver the water below; they are fixed or attached to the walls of buildings of stone usually with flanges of lead, which are secured by means of spike nails,—iron and other metals having superseded lead where brick is used or economy requires the substitution.

The varieties of water-closet apparatus, of which Under· hay’s patent is one of the best, are too numerous to be here described. Pumps of all kinds and powers are amongst the other matters coming within the plumber’s province, together with cocks, bosses, ferules, washers, valves, balls, grates, traps, funnels, service boxes, and a numerous collection of other articles.

A metal occasionally used for roofs in lieu of lead is known by the name of Wetterstedt’s patent marine metal. It is composed of lead and antimony. Its advantages are its malleability, great tenacity, elasticity, and durability, and its resistance to acids, oxidation, and the action of the sun and atmosphere. It is manufactured in sheets of certain sizes, from 3 ft> to 8 ounces per foot, according to the purposes for which it is required, the latter weight being useful for lining damp walls. It should be secured with wrought copper nails. A patent metallic canvas is also manufactured of various substances and strength, serving for waterproof and secure covering.

Sheet copper was formerly used on account of its lightness to cover roofs and flats. The thickness generally varied from 12 to 18 ounces per square foot. It was laid like lead, but the plates being of small size were soldered together. It will be well to notice that water collected from copper channels must not be used for culinary purposes, as a film of verdigris is formed, which is poisonous. Copper is much used for roofing in foreign countries.

Lead and copper, where economy is required, are superseded by zinc, which is not only much cheaper, but when good is nearly as durable, and is not so liable to be corrugated by the action of the sun. Zinc is subject to oxidation; but the oxide, instead of scaling off as that of iron does, forms a permanent coating on the metal. Its expansion and contraction are greater than those of any other metal. Zinc sheets as manufactured vary in quality, some being very brittle. That supplied by the Vielle Montagne Zinc Mining Company possesses a high reputation for purity and excellence. Zinc must be laid like lead, without fixing either by nails or solder. No. 13 gauge, weighing 19 oz. 10 drs., is the least for roofs, flats, and gutters on boarding. No. 14, a medium thickness, weighing 21 oz. 13 drs., is used for roofs and flats; and No. 15 or 16, weighing 24 oz. and 26 oz. 3 drs. per foot superficial, for best work and roofs without boards. Zinc pipes are extensively used as chimney pots; stamped and moulded ornamental zinc for dormers, Mansard roofs, vanes, guttering, and rain-water pipes, cisterns, &c.; and perforated zinc for blinds and for ventilation.

Tin cannot class with the building materials in England, although it is extensively used for covering roofs in America and in Russia.

The best publications on this trade are the makers’ price books and lists of articles made and sold by them. See also the article Metallurgy.

Plaster-wobk.

No art in the economy of building contributes more to produce internal neatness and elegance, and no one is less absolutely important, so far as the use and stability of a structure are concerned, than that of the plasterer. The very general application of plaster is of comparatively late date; for wainscoted walls, and boarded or boarded and canvased ceilings, or naked joists alone, are frequently found in houses of rather over a century old, both in England and on the Continent; and a return to this state of completion in the present day is the result of the attempts of the mediaeval school of architects, and their cry of “no shams,” which has not been quite successful among themselves, for plaster and cement are used by many. The walls of houses were formerly plastered above the wainscoting and coloured, while the ornamented plaster ceilings of the time of Henry VIII., Elizabeth, and .Tames I., are still the admiration of lovers of the art. Still earlier specimens of the plasterer’s skill are extant in the pargetted and ornamented fronts of halftimber houses.

For the more common operations of plastering comparatively few tools and few materials are required. The plasterer is attended by a labourer, who supplies his boards with mortar, and by a boy on the scaffold with him to feed his hawk, which is a piece of wood about 10 inches square with a handle under it, for carrying up small portions of plastering mortar to the wall or ceiling, to be there delivered and spread by the trowel, a thin plate of hardened iron or steel with a wooden handle, similar to that used by the bricklayer. The plasterer is obliged to keep this implement particularly clean and dry when he is not actually using it, lest it rust in the slightest degree, as it is clear that the brown oxide of iron would sadly discolour his finer work on touching it again with the trowel. He is necessarily furnished with a lathing hammer, a hand float, a quirk float, and a derby or darby, which is a long two-handled float for forming the floated coat of lime and hair; brushes for fine or rough work; three or four jointing trowels for mitres, &c.; jointing rules; moulds for cornices, which are of wood, but for work of any importance the frame is made of wood and the outline cut out of a copper (or more usually zinc) plate,—these are inserted in the wooden stock, and narrow pieces of wood are fixed to the moulds transversely to guide and steady them along the screeds; a straight edge, wherewith to bring the plastering on a wall or ceiling to a perfectly even surface by traversing it in every direction; a screen, having metal wires to act as a sieve for separating the coarser materials which enter into the composition of plastering mortar,—these are thrown against its outer face, to separate the particles which are too large for the purpose from the finer,—the sand and lime, too, are mixed much more efficiently and completely by screening them together than in any other manner; a spade and hod like those of the bricklayer’s labourer; a rake to separate the hair used in the mortar and distribute it throughout the mass; and a server for the hawk boy to beat up the mortar, and to deliver it in small pats on the hawk.

The plasterer, as the term imports, works in plastic, adhesive compositions, which are laid on walls, both internally and externally, to stop crevices, reduce inequalities, and produce an even, delicate surface, capable of receiving any decoration that may be applied to it, either in colour or otherwise. These compositions are as various as the modes of applying them, the rudest being a compost of loam, a marly clay, and lime; this is used only for the commonest purposes, and being laid on in one coat, is washed over with a thin mixture of lime and water, a process termed lime-whiting. There are many grades from this to the highest work of the plasterer,—the making imitations of marbles and other costly stones, from the purest calcined gypsum mixed with a solution of gum and isinglass and colouring matter to produce the required imitation. His materials are laths, lath nails, lime, sand, hair, and plaster, a variety of stuccoes and cements, together with various ingredients to form colouring washes, &c. Scaffolding is not generally required for new work, but with old work it is sometimes necessary. Under ordinary circumstances, the plasterer is enabled to wash, stop, and whiten the ceilings and walls of rooms from trestles, with boards laid across them. In lofty saloons and halls, churches, &c., scaffolding is indispensable. It is necessary, too, to a front that is to be plastered in any way; but this may be afterwards washed, repaired, and coloured from a ladder, without the intervention of a scaffold, except perhaps the suspended scaffold now so much used.

Laths are narrow strips of some straight-grained wood, generally of fir, though oak laths are sometimes used, in lengths of 3 and 4 feet, or to suit the distances at which the joists of a floor or the quarterings of a partition are set, and in thickness from ⅜th to f ths of an inch; those of the greater thickness are called lath and a half. Lath nails are either wrought or cut; cut nails are in common use in England with fir laths. Coarse stuff is composed of ox or horse hair from the hide, in addition to lime and sand mortar; this is intended to act as a sort of mesh to net or tie it together, and form a coarse but plastic felt. The hair should be long, and free from all grease and filth. Road drift is unfit to be used in place of clean sharp sand in mortar, unless it be completely cleansed from all animal and vegetable matter, and of mud and clay. Fine stuff is made of fine white lime, exceedingly well slaked with water, or rather macerated in water to make the slaking complete; for some purposes a small quantity of hair is mixed up with this material. The mere paste, when allowed to evaporate until it is of a sufficient consistence for working, is called putty. Gauge stuff is composed of about three-fourths of putty and one-fourth of calcined gypsum or plaster of Paris; this may be mixed only in small quantities at a time, as the plaster or gauge renders it liable to set very rapidly. Bastard stucco is made of two-thirds fine stuff, without hair, and one-third of very fine and perfectly clean sand. Common stucco is composed of about three-fourths of clean sharp sand and one-fourth of the best lime, well incorporated. This must be protected from the air from the time it is made up until it is required to be laid on the walls. Parker’s (or Parker’s Roman) cement, when of good quality, with fine clean sharp sand, in the proportion of about three of sand to one of cement, and well executed, forms a very good external coating for walls. It is vulgarly called “comps,” a contraction of “composition.” Portland cement, so called because the mortar formed by it when mixed with sand is supposed to present the appearance of stone from the Portland quarries, is in much esteem for an outside stucco, as the colour to which it dries is sufficiently agreeable to the eye without any colouring wash, whereas Parker’s cement is too often of a dark dirty tint, requiring painting or colouring to render it tolerable. Portland cement is also much valued as being proof against water when used as a mortar in setting brickwork, and in the composition of concrete for foundations. The patent selenitic cement already described (page 459), is stated to be an excellent substitute for Portland cement; it takes double the usual quantity of sand, and is stronger even then than ordinary mortar. Plastering is finished in much less time than by the common mode.

A class of cements capable of taking a brilliant polish resembling marble, and consequently very suitable for internal decoration, deserves to be mentioned. The chief of these are Keene’s marble cement and Parian cement. They become excessively hard in a short time, and are capable of being painted in a few days. The principal component is said to be obtained by the precipitation of alum by an alkali, which gives a white powder of great brilliancy. Tints can be made up with these cements for coloured decorative work. Cements made by the mixture of oil with various substances were formerly much used both here and abroad. The best known in England was called Hamelin’s mastic, that in France the mastic de Dhil. These cements being very expensive, and requiring to be constantly painted, have now gone nearly out of use. For outside plastering they form a very fine clean surface, as may be seen in the quadrant in Regent Street and other buildings of that date, but in many instances it has been taken otf and Portland cement substituted.

Blue lias lime was formerly greatly esteemed as a cement for outside work, but the carelessness of the burners has tended much to limit its use, there being a large proportion of underburnt stone left in it. The workmen also would not take the requisite pains for slaking this lime, and manufacturers therefore ground it, by which operation the core becomes mixed up with the properly burnt material, and the efficiency of the lime is destroyed. The lumps should be broken as small as nutmegs, then immersed in water on a sieve until air-bubbles freely rise to the surface; the lime so wetted is to be left in a heap covered by damp sand for twenty-four hours, after which time it should be screened and mixed with the proper quantity of sand and the least possible quantity of water. To one of lime may be put not more than from two to two and a half of sand. When slaked it does not increase in bulk.

The various coatings of plastering are distinguished thus. On laths, plastering in one coat simply is said to be laid, and in two eoats, laid and set. In three-coat plastering on laths, however, the first is called the pricking up, the second is said to be floated, and the third set. On brick or stone walls, plastering in one plain coat is termed rendering; with two coats, a wall is said to be rendered and set; and in three, rendered, floated, and set.

Before beginning to lath a ceiling, the plasterer proves the under face of the joists, to which he has to work, by applying a long straight edge, and makes up for any slight inequalities in them, when the work is not to be of a very superior description, by nailing on laths or slips to bring them as nearly even as he can. When the inequalities are great, or if the work is to be of fine quality, he recurs to the carpenter, who takes off inordinate projections with his adze, and nails on properly dressed slips w here the joists do not come down low enough, and thus brings the whole to a perfect level. This operation is called firring, or furring. If it be a framed floor with ceiling joists the plaster has to work to, it is tolerably sure to be straight; but the carpenter must have firred down on the beams or binders to the level of the ceiling joists, unless the ceiling joists have been nailed to the beams or binders, when nothing of this kind is necessary. If a ceiling is to be divided into compartments or panels, the projecting or depending portions must be bracketed or cradled down to receive the laths. It is an important point to be attended to in plastering on laths, and in ceilings particularly, that the laths should be attached to as small a surface of timber as possible, because the plastering is not supported or upborne by its adhesion or attachment to the wood, but by the keying of the mortar itself, which passes through between the laths, and bends round over them. If then the laths are in constantly recurring contact with thick joists and beams, the keying is as constantly intercepted, and the plastering in all such places must depend entirely on the portions between them which are properly keyed. Under a single floor, therefore, in w hich the joists are necessarily thick, a narrow fillet should be nailed along the middle under the whole length of them all, to receive the laths and keep them at a sufficient distance from the timber to allow the plastering to key under it; thus too the surface may be made more perfectly even, as it is in single floors that inequalities mostly occur. This being all arranged, the plasterer commences lathing. The laths should be of the stronger sort. Thin weak laths, if used in a ceiling, are sure to produce inequalities, by sagging with or yielding to the weight attached to them; one or two weak ones in a ceiling of otherwise strong laths may be the ruin of the best piece of work. They should be previously sorted, the weak, crooked, and knotty, if there be such, being reserved for inferior works, andthe best and straightest selected for the work of most importance, so that the workman shall find none to his hand that is not fit to be brought in. Taking a lath that will reach across three or four openings, he strikes a nail into it on one of the intermediate joists, at about three-eighths of an inch from the one before it, and then secures the ends of that and the one that it meets of the last row with one nail, leaving the other end of the lath he has just set to be secured in the same manner with that which shall meet it of the next bay in continuation. It is of importance also that in ceiling-w ork he pay attention to the bonding of his work. In lathing on quartering partitions and battened walls, the bonding is not a matter of much importance; nor is the thickness of the timbers behind the latter of so much consequence as in a ceiling, because the toothing which the thickness of the lath itself affords to the plastering is enough to support it vertically; but, nevertheless, the more complete the keying, even in works of this kind, the better, as the toothing above will not protect it from any exciting cause to fall forwards, or away from the laths. The thinner or weaker sort of lath is generally considered sufficiently strong for partitions.

When the lathing is completed, the work is either laid or pricked up, according as it is to be finished with one, two, or three coats. Laying is a tolerably thick coat of coarse stuff or lime and hair brought to a tolerably even surface with the trowel only; for this the mortar must be well tempered, and of moderate consistence,—thin or moist enough to pass readily through between the laths, and bend with its own weight over them, and at the same time stiff enough to leave no danger that it will fall apart,—a contingency, however, that in practice frequently occurs in consequence of badly composed or badly tempered mortar, unduly close lathing, or sufficient force not having been used with properly consistent mortar to force it through and form keys. If the work is to be of two coats, that is, laid and set, when the laying is sufficiently dry, it is roughly swépt with a birch broom to roughen its surface, and then the set, a thin coat of fine stuff, is put on. This is done with the common trowel alone, or only assisted by a wetted hog’s bristle brush, which the workman uses with his left hand to strike over the surface of the set, while he presses and smoothes it with the trowel in his right. If the laid work should have become very dry, it must be slightly moistened before the set is put on, or the latter, in shrinking, will crack and fall away. This is generally done by sprinkling or throwing the water over the surface from the brush. For floated or three-coat work, the first, or pricking up, is roughly laid on the laths, the principal object being to make the keying complete, and form a layer of mortar on the laths to which the next coat may attach itself. It must, of course, be kept of tolerably equal thickness throughout, and should stand about one-quarter or three-eighths of an inch on the surface of the laths. When it is finished, and while the mortar is still quite moist, the plasterer scratches or scores it all over with the end of a lath in parallel lines from 3 to 4 inches apart. The scorings should be made as deep as possible without laying bare the laths; and the rougher their edges are the better, as the object is to produce a surface to which the next coat will readily attach itself. When the pricked up coat is so dry as not to yield to pressure in the slightest degree, preparations may be made for the floating. Ledges or margins of lime and hair, about 6 or 8 inches in width, and extending across the whole breadth of a ceiling or height of a wall or partition, must be made in the angles or at the borders, and at distances of jιbout 4 feet apart throughout the whole extent; these must be made perfectly straight with one another, and be proved in every way by the application of straight edges; technically these ledges are termed screeds. The screeds are gauges for the rest of the work; for when they are ready, and the mortar in them is a little set, the interspaces are filled up flush with them; and a derby float or long straight edge being made to traverse the screeds, all the stuff that projects beyond the line is struck off, and thus the whole is brought to a straight and perfectly even surface. To perfect the work, the screeds on ceilings should be levelled, and on walls and partitions plumbed. When the floating is sufficiently set and nearly dry, it is brushed with a birch broom as before described, and the third coat or set is put on. This for a fine ceiling that is to be whitened or coloured must be of putty; but if it is to be papered, which is very unusual, ordinary fine stuff, with a little hair in it, will be better. Walls and partitions that are to be papered are also of this latter, or of rough stucco, but for paint the set must be bastard stucco trowelled. This coat must be worked of exactly the same thickness throughout, to preserve to the external surface the advantage that has been obtained by floating. For all but the last-mentioned, the set on floated work, the trowel and brush are considered sufficient to produce fine and even work; but trowelled stucco must moreover be hand floated. In this operation the stucco is set with the trowel in the usual manner, and brought to an even surface with that tool to the extent of two or three yards. The workman then takes the handfloat in his right hand, and rubs it smartly over the surface, pressing gently to condense the material as much as possible. As he works the float he sprinkles the surface with water from the brush in his left hand, and eventually produces a texture as fine and smooth almost as that of polished marble.

But lathing and plastering on laths as practised in England is at best a very flimsy affair, and greatly requires improvement. Stronger laths than the laths commonly employed, put on further apart, and with headed wrought nails, and the plastering laid on upon both sides in upright work, or both above and below the ceilings at the same time, two men working against one another, will produce work in some degree worthy of the name. The practice of the French in this respect is well worthy the consideration, and to a great extent the imitation, of English plasterers.

The process of plastering on the naked brick or stone wall differs but little, except in name, from that we have described as the mode on lath. The single coat is called rendering, and it need differ only in the quantity of hair, which may be less than is necessary for laying on lath, and in the consistence of the mortar, which may be made more plastic, to work easier, and because in a moister state it will attach itself more firmly to the wall; the wall, however, must itself be well wetted before the rendering is applied. The set is the same, and is put on in the same manner as to two-coat work on lath. For three-coat or floated work, the first or rough rendering should be made to fill up completely whatever crevices there may be in the work behind it, and be incorporated with it as much as possible. As its name imports, its surface may, indeed should, be rough; but it is not scratched or lined as the similar coat on lath is. For this, too, the wall must be previously wetted, that the mortar may the better attach itself to it. For the floating, screeds must be formed as before described, and the consecutive process is exactly the same as on lath, both for the floated and for the set coat. In almost every case in which plastering is to be floated, the workman finds a guide for the feet of his wall screeds in the narrow grounds which the joiner has previously fixed for his skirtings; from these he plumbs upwards, and makes his work perfectly flush with them.

Mouldings and cornices (as large combinations of mouldings and flat surfaces immediately under the ceilings of rooms are called) are formed with running moulds, and are generally executed before the setting coat is put on the walls and ceiling. If the cornice do not project more than about an inch and a half, or 2 inches, from the ordinary work, a backing of lime and hair will be sufficient; and if any one part only happen to be more than ordinarily protuberant, a row of nails from 6 to 12 inches apart stuck into the wall or ceiling in the line of that part will give it sufficient support. But if the general mass of the cornice be more than that amounts to, and extend more than 6 or 8 inches along the ceiling, it must be bracketed out, and the bracketing lathed and pricked up, as for ordinary work. This pricking up, or other preparation, must of course be perfectly set before the cornice is run; and there should be one-fourth of an inch at least of clear space between the preparation and the mould in the nearest part. A wooden screed or parallel straight edge is tacked on with brads to the wall, and another on the ceiling, if the cornice be large and heavy, as guides or gauges for the mould, whose rests are chased to fit them; and then one man laying on gauge stuff in an almost fluid state with an angular trowel, another works the mould backwards and forwards over it, which strikes off what is superfluous, and gives the converse of its form to the rest. The mould is never taken down from the work at right angles to the line of it, but is drawn off at the end, so that none of the parts of the moulding or cornice is injured or torn by it, which must otherwise frequently be the case, from the peculiar forms at times given to the details. If a cornice be too large and heavy to be executed at once, it may be done in the same manner at two or more times, in so many parts; and if any part or parts of a moulding or cornice is to be enriched, the space for it is left vacant by the mould, and the enrichment is afterwards supplied. As a cornice cannot be completed up to the angles by the mould, it is worked by hand in those situations to a joint. The joinings are termed mitres, and in forming them the plasterer uses the jointing tools we have already described.

Models for enrichments are made by the modeller, according to the design or drawing submitted to him, and from them the plasterer makes wax or gelatine moulds, or, as in ordinary practice, the modeller supplies the moulds in which the ornament is cast in plaster of Paris. If the ornament be in recurring lengths or parts, as is usually the case, only one length or part is modelled, and casts of as many as are required are taken from the mould; some single ornaments, again, which are very large, require to be moulded and cast in parts, which are put together by means of cement. When the cast ornaments are sufficiently dry the pieces are scraped and trimmed, and the joints made clean and even; and they are set in the cornice with plaster of Paris, with white lead, or with a composition called iron cement, as the case may require. If the castings have something in the cornice to rest upon, the first will do; but if there is nothing to retain or attach them but the cement, one of the last two must be used. Flowers and other ornaments on ceilings which are too large and heavy to be trusted to adhesive matter alone, must be screwed to wooden cradling behind and above them.

In plastering a wall with common stucco (and its use is mostly for outside work), the first thing to be done is to remove the dust from it by brushing, and then to wet very completely with water If the wall to be stuccoed be an old one, or one of which the joints have been drawn, the mortar of the joints must be chipped or even raked out, and the bricks picked, to expose a new and porous surface to the plastering before brushing and wetting. The wall is then covered with stucco in a fluid state, applied with a broad and strong hog’s bristle brush, like common whitewashing. When this is nearly dry the stucco must be laid on as in common rendering, unless the work is to be floated, when the process is nearly similar to that in floated plastering. Screeds must be formed at ehe highest and lowest extremities of the wall, or of that part of the wall which is in the same vertical line, and is not intercepted by string courses, and be returned at the angles, putting the whole surface into a sort of frame. These must be made perfectly straight and plumb, so as to be quite out of winding by the careful application of the plumb-rule and straight edge. Inner vertical screeds must then follow at three or four feet apart across the whole surface, and be made to range exactly with the outer ones, and then the interstices must be filled in as before. As the work is made good it must be well rubbed with the hand float, as in the execution of trowelled stucco internally, to compress the material, and produce a hard, even, and glossy surface. Preparations for cornices and other projections from the straight surface of the work must have been previously made in or on the brick or stone-work by the protrusion of bricks, tiles, or whatever may be best suited to form a core; and the mouldings and cornices are run with moulds, in the manner described for the same things internally, only that in work of this kind no plastic material but the stucco itself is used,—that is, there is no preparation of any softer material than the stucco itself put under it. In running cornices in this material, workmen are very apt to mix a little plaster of Paris with the stucco to make it set under the mould, and thus give sharpness and fulness to the mouldings; but this should not be permitted; for the plaster is not qualified to stand the weather as the stucco is, and, if mixed with it, will produce premature decay. When the stucco is perfectly dry, it may be painted in oil colours, or be coloured in distemper; and in either case it is generally (though not invariably) ruled over the surface with a lead point, to give it the appearance of gauged stone-work.

Rendering in the Roman and Portland cements is executed almost exactly in the same manner as stucco rendering is, only that it is laid on the saturated wall directly, without the preliminary operation of roughing in, or washing the surface with a solution of the material. The same process, too, is followed in floating this cement, and with the same exceptions; and as, in addition to its superior hardness and capacity for duration, it is a quicksetting cement, it is far preferable to any of the common stuccoes for running cornices, mouldings, <fcc. These cements may, like stucco, be painted in oil, or coloured; but instead of a size colour, which is used for almost every other purpose in plastering, the colour for this composition is mixed with diluted sulphuric acid. This too may be lined and tinted to imitate stone and stone-work of any description.

It may not be amiss here to refer to some of the causes of the premature decay which takes place in stuccoes and cements when used externally as a coating to walls. The primary cause is the presence of muddy earth and decayed animal and vegetable matter in the sand used with the lime and cement. To this may be added frequent impurities in the limes and cements themselves, particularly of argillaceous matter in the former, and sometimes the too great proportions of lime or cement to sand. These things might, however, remain quiescent for a long time, if the work were well protected from access of moisture, which is the grand exciting cause. The paint, or distemper wash, on the surface, is generally sufficient to prevent the rain which may beat against a vertical face from penetrating, especially if the work have been well hand-floated and trowelled, to make it close and compact; but the evil arises from exposure above, and from the numberless horizontal unfloated surfaces which are constantly presented. These receive and collect the water, and convey in streams over the vertical surfaces what is not immediately absorbed; and the work thus becoming saturated, frost seizes and bursts it, or warmth calls the vegetative powers of the impurities in it into action, and the whole is covered with a green sward. Let the sand of which a plaster composition is to be formed, whether with lime or cement, be washed until it no longer discolours clean water, and be well compounded with cementitious matter free from impurities with which it is so frequently charged; let the work be well hand-floated and trowelled, particularly on the backs or upper horizontal surfaces of projections, and protected above by projecting eaves or otherwise; and the work, with common care and attention to paint or distemper at intervals, will last as long as anything of the kind can be expected, or is found, to last auywhere.

A cheap and useful covering for external walls, which are protected by projecting eaves, in plain buildings, is rough cast. This is executed in the following manner :—The surface is first roughed, or indented, and then well brushed with a stiff brush to remove all dust or loose earth. It is then covered with the rough cast, which consists of a small quantity of mortar diluted with water, to which a trowel of pure lime is added to make it about the thickness of cream. After the workman has done all within his reach the scaffolding is lowered, and he proceeds with the remainder. Another process is somewhat dearer. After having been roughed or indented, the wall is sprinkled with water, and then rendered with lime and hair; and when that is set, another coat of the same material is superadded, laid as evenly as it can be without floating, and as soon as a piece of two or three yards in extent is executed, the workman lays on it an almost fluid mixture of clean fine gravel and strong lime, which have been well mixed together. This is immediately washed with any ochreous colour that may be desired, and the whole dries into one compact mass. A third process, called stuccoing, is performed by the workman laying on a few trowels of stucco, which he spreads as much as possible; a second workman provided with a brush and a small wood float follows him, and after sprinkling the mortar with water he rubs over that part he has wetted with the float, and at the same time it may be whitened with lime alone. When the lime is very good this makes very good work.

In renovating and repairing plastering the whole surface is first well washed to remove the dirt which may have attached itself, and as much of the earthy matter of the previous coat of whitening or colouring as will come away; any injuries the work may have received, such as cracks and fractures, are then repaired; and when the new stuff is quite dry, the joinings are scraped to produce an even surface, and the whole is again whitened or coloured once or twice or offener as may be required, to make it bear out well. Stuccoed walls which have been painted must be well rubbed with pumice stone, to take off the old paint as much as possible before the new work is proceeded with.

For a decoration to rooms having plastered walls, instead of papering or flat painting, or for a suitable ornamentation for the interior of churches built at small outlay, the old system of pargetting has been revived. The usual stucco or other plaster finish is, while still wet, stamped over with a pattern made of brass, or for rougher work of wood, to any geometrical or other form in accordance with the style of architecture; this indents the surface. It may be left all of one colour, or the open portions of the device may be filled in with another coloured plaster.

Another revived method, especially for outside work, now much in use is called sgraffito. It was in vogue with the Italian artists about two centuries since, who executed some very elaborate specimens of ornamentation with it. The process is briefly as follows :—First, mix with the mortar some colouring substance of the tint desired for the pattern of the design; then apply a thin coat of it to the wall. When this coat is nearly dry, apply on it another coat similarly prepared but of the colour intended for the grounding, and then, a mould having been prepared in zinc of the exact outline of the pattern, it is to be applied to the surface, its outer edge marked round, and with a sharp tool as much of the upper coat of plaster is cut away as comes within the pattern, down to the face of the lower coat. By a careful arrangement of pattern, a considerable variety of colouring may be employed; and even three coloured coats can be put on, cutting through sometimes one, sometimes two, as may be desired to represent the design. As the colour is in the material itself, there is no fear of its scaling and so presenting a bad appearance; and it is a comparatively cheap process for the decoration of a new surface which cannot be painted for some time. The process has been adopted in England with coloured cements for outside work.

Under the plasterer’s trade it may be desirable to mention some of the varieties of artificial marbles, scagliola, and other similar work for the decoration of buildings. Scagliola is a species of plaster or stucco invented about 1600-50 in Italy. The work is lathed and plastered as usual, and then the artist commences, preparing his material, which is composed of the purest gypsum broken into small pieces and calcined, passed through a very fine sieve and mixed up with glue, isinglass, &c. In this solutiou the colours are diffused that are required to be imitated in the marble; or the colours are prepared separately, and afterwards mingled and combined nearly in the same manner that a painter mixes the primitive colours on his palette to compose his different tints. When the gypsum is prepared and mingled, it is laid on the plaster, and then floated with proper moulds of wood, the artists during the floating using the colours necessary for the imitation, by which means they become mingled and incorporated with the surface. The process of polishing follows, first by means of pumice stone, then with tripoli and charcoal and fine and soft linen; after this the surface is rubbed with a piece of felt dipped in a mixture of oil and tripoli, and last of all with pure oil. The imitation may be so good that except by fracture or by sound it cannot be discovered to be a counterfeit.

Marezzo marble is made of cement mixed with fibre for strength and to resist a blow. Slabs are bedded on plaster of Paris, and with cramps and dowels like marble. Every variety of marble can be imitated in it, and it receives a high and permanent polish. The Marbre Universel Company have put forward a new manufacture of a similar description.

Modelling, Carved Work, and Gilding.

The modeller copies the drawings of the designs which may have been prepared for the enrichments, in whatever material they ai e to be cast, whether in plaster, in metals, or in composition of any kind, for the plasterer, smith, or decorator. The model is made of soft wood, by the usual chisels and gouges, or in a finely-tempered and plastic clay called modelling clay, or in wax. The modeller works the clay with his fingers, assisted by a few ivory, bone, or steel tools for finishing off neatly and sharply, and for working in parts which he cannot reach with his fingers. The best workman is one who can do most towards producing the required forms with his fingers, unassisted by artificial tools, as a greater degree of ease and freedom almost always results from the use of the hands alone. The model being completed, it is moulded, that is, a mould or moulds are made from it of a preparation of resin or of gelatine, sometimes of plaster of Paris; the moulds, if they have to be formed in portions, are fitted exactly to each other at the edges, and in these moulds casts in plaster of Paris or other material are made to any extent that may be required. For smith’s work the wood model is sent to the founder for casting in metal. For carved work, such as caps of columns, shields, medallions, consoles, <kc., the model may be sent to the mason or stone carver for the completion of the block, which may have been left in a boasted state by the mason when setting it.

The modeller having some pretensions to be considered an artist rather than a mere artificer, is for the most part paid according to his merits, rather than for so much time, according to the ordinary mode of determining the value of artificers’ works.

The carver is strictly an independent artist, whose business it is to cut ornaments and enrichments in solid and durable material, such as stone and wood, so that, like the modeller, he must be paid according to the taste and power he may exhibit in his works, rather than as a common artificer. The art of carving has, however, been in a great measure superseded by modelling and casting. In works of a free style, or of a mediaeval character, the carver is often left free to exercise his own taste and fancy or talents in the execution, with or without a sketch by the architect before him. The decorator, in addition to casts in plaster of Paris, now makes use of composition ornaments, which are formed of a mixture of whiting and glue pressed into moulds; or of papier mâché, which is paper pressed into moulds; or of a composition of a thin coat of plaster of Paris poured into the mould, and then covered with coarse canvas, the result being to all appearance a plaster cast, but it is far lighter in weight,—a figure the size of life being readily moved about by one person. It was an old process revived by the late Mr Owen Jones, and well carried out for him by Μ. Desachy, in the elaborate ornamented ceiling at St James’s Hall, Piccadilly.

Gilding is applied to castings as well as to carvings; but the former being, almost as a matter of course, less sharp and spirited in their flexures and details, as well as less firm in substance than the latter, castings can less bear to be further subdued by the application of foreign matters to their surfaces than carvings may. Gilding is the application of gold leaf to surfaces, which require, however, to be previously prepared for its reception. The work is first primed with a solution of boiled linseed oil and carbonate of lead, and then covered with a fine glutinous composition called gold size, on which, when it is nearly dry, the gold leaf is laid in narrow slips with a fine brush, and pressed down with a piece of cotton wool held in the fingers. As the slips must be made to overlap each other slightly, to insure the complete covering of the whole surface, the loose edges will remain unattached; these are readily struck off with a large sable or camel-hair brush, fitted for the purpose; and the joints, if the work be dexterously executed, will be invisible. This is called oil gilding, and it is by far the best fitted for the enrichment of surfaces in architecture, because it is durable, and is easily cleaned, and does not destroy or derange the forms under it so much as burnished gilding does. The latter requires the work to be covered with various laminae of gluten, plaster, and bole, which last is mixed with gold size, to secure the ad hesion of the leaf.

Glazing.

The business of the glazier, the manufacture of whose material has of late years improved and progressed in a very remarkable degree, may be confined to the mere fitting and setting of glass; even the cutting of the plates up into squares being generally an independent art, requiring a degree of tact and judgment not necessarily possessed by the building artificer.

The glazier is supplied with a diamond or other cutting tool, laths or straight-edges of various lengths, a square, a glazing-knive, a hacking knife, a hammer, a duster, a sash-tool, a two-foot rule, and a machine called a glazier’s horse, which he fixes outside a window sill, and stands on to reach the upper panes for glazing or cleaning purposes, without removing the sash, and so injuring the beads and paint.

His materials are simply glass, putty, and priming or paint. The glass is supplied by the glass-cutter, of the qualities and sizes required for the particular work to be executed. The putty is made by the glazier himself, or by a labourer, of fine clean powdered chalk or whitening, well mixed and combined with linseed oil, and kneaded to the consistence of dough. No more putty should be made at once than is likely to be worked up in the course of a few days, as, the oil drying out, it becomes hard and partially set, and is therefore less available for its purposes. Priming is a thin solution of white (with a little red) lead, mixed in linseed oil. For ordinary glass, the sashes are sent to the glazier from the joiner, after having been fitted into their places, and only require to be glazed before they are permanently set or hung. Supposing that no preliminary process is required, such as stopping (the result of bad joiners’ work) and knotting (and knotty stuff should not be admitted in sashes), the sashes require to be primed. The priming is laid on every part of the sash except the outer edges of the styles and of the bottom and top rails, with the sash tool or painting brush, that is, if the sashes are intended to be painted; for if not, the rebates only 1nu3tbe primed. The object of this is to prepare the material of which the sash is composed for the reception of the putty, which would not otherwise attach itself so firmly as it does after this preparation. The priming being sufficiently dry, the workman cuts the panes of glass down into their places, making every one fall readily into the rebates without binding in any part; indeed the glass should fit so nicely as not to touch the wood with its edges anywhere, and yet hardly allow a fine point to pass between it and the sash-bar or rebate, the object being to encase it completely in putty, and yet that the putty should not be in greater quantity than is absolutely necessary. The glass being fitted or cut down, the workman takes the glazing-knife in his right hand, and a lump of putty in the palm of his left, the sash being laid on its face, that is, with the rebates upward, before him; with the knife he lays a complete bedding of putty on the returning narrow stops of the rebates, all round to every pane. This being done, the panes of glass are put on it as they have been fitted, and every one is carefully rubbed down with the fingers, forcing the putty out below and round the edges of the glass, until they are nearly brought into contact with the wood or other material of the sash. The rebates are then filled in with putty behind, the mass forming exactly a right-angled triangle, its base being the extent of the stop of the rebate, and its perpendicular the depth from the glass to the outer edge of the rebate; and the third side or hypothenuse is neatly smoothed off. The sash being then turned on its edge and held upright by the left hand, the protruded putty of the bedding, or back putty as it is called, is struck off with the knife, and the section of it neatly drawn. The sashes are now deposited on their faces to allow the putty to set, and then they may be hung and painted.

To very large squares, and to plate glass, needle points, or small nails called sprigs, are used to retain the material securely in its place while the putty is soft and yielding. These have to be carefully inserted, for if they fix the glass it is apt to fly at any sudden vibration. Large squares and plate glass are usually inserted after the sashes are hung, to prevent risks of breakage. Where the bar and frame can be made to allow of it, large squares are secured in their place by wood beads screwed to the rebate in lieu of putty. In this case the edge of the glass is first covered with a piece of flannel, or thin india-rubber, to fill up crevices, and so prevent admission of dust, and stop any current of air.

Lead-work, as it is termed, is the glazing of frames rather than of sashes with small squares or quarries of glass, which are held together by reticulations of lead; and these are secured to stout metal bars, which are fixed to the window frames. Leaden reticulating bars are grooved on their edges to receive the quarries, and are tied by means of leaden ribands or wires to the saddle bars, which, in their turn, are affixed to the stouter bars before mentioned, if the bay or frame be so large as to require both. This is now extensively carried on in the painted glase window shops, where the glass is cut to patterns, and shows outlines of figures, costumes, <fcc. “Stained glass” is obtained by mixing colours in the pot while in the furnace, hence the term “pot metal” for it. A kind of coloured glass has only a skin of colour on one side of the white material, and hence is termed “flashed glass.”

Besides all the varieties of clear glass, the glazier has now at his command the many qualities of obscured glass, beyond the ground and painted glass of former days; the lace-pattern glass, executed by laying a pattern on the material which'has been covered with a varnish, placing it in a box filled with a fine powder, which when shaken adheres to the varnished portions, and then putting it in a kiln where it becomes fixed; the patent rough plate for conservatories, workshops, <fcc,, and its fluted varieties; the rough cast plate for workshops and storehouses; the stained ornamented quarry for church windows, &c. Lastly, there is the engraving on glass by aid of the sand blast,—a new and easily managed method, consisting in a jet of air blown violently through a tube, carrying with it particles of fine sand. The action is very rapid, and it reduces the surface in a few minutes to the condition of ground glass. A piece of lace, however, is sufficient to arrest the action of the sand. Reece’s patent embossed and coloured glass is useful for screens and for windows which are not meant to be looked through.

Coming within the scope of the glazier’s business is the novel pavement light, consisting of a frame of iron cast with small many-sided apertures, into which are placed a series of dome-shaped or prism-shaped blocks of glass, reflecting the light falling upon them. They distribute the light to a greater extent than a piece of rough plate-glass, and like Chappuis’s and other reflectors require to be kept clean. Moore’s window ventilator allows of the admission of air through its louvres, which are worked by a wire or cord as necessary. Hartley’s patent perforated glass attempts to gain the same end by small slits formed in the pane.

For publications relating to the glazier’s chief material, see the article Glass. For patterns of lead-work, see Shaw’s reprint of W. Gidde, Booke of Sundry Draughtes, 8vo, 1615.

Smith-work and Gasfitting.

The smith is the worker in wrought metals of all kinds required chiefly by the carpenter and joiner, λvho fixes them in the building. Smithery is the art of uniting several lumps of iron into one lump or more, and forging them to any desired shape. The earlier parts are done at the forge and on the anvil with the hammer, and hence is produced “wrought work,” whether for useful or for ornamental purposes. Machinery has been brought extensively to the smith’s assistance, for rolling, drilling, planing, &c. The ornamental portion of his work is wrought iron shaped by hand into devices and patterns according to the various styles of architecture, as in gates, railings, standards, hinge bands, locks, handles, knockers, lanterns, candlesticks, and other lighting contrivances, which are also executed in brass-work and in cast-iron.

The founder’s work is all cast metal, such as for ornamental gates and railings, rain-water pipes, cistern heads, and other portions, guttering, stable-fittings, coal-plates, &c. These commonly require to be fitted and fixed by the smith. The founder supplies all fire-grates, stoves, and other apparatus for warming and also for ventilation.

The gasfitter is a smith who supplies and fixes cast-iron pipes for diameters above two inches, and wrought iron for those of smaller bore, where gas is required to be used. A three-quarter inch pipe is considered by some as the least size to be used even for supplying rooms on an upper story; tin or composition metal pipes are fixed for sizes under half an inch, and also flexible tubes. It is recommended that no pipes should be embedded in the plastering, as is usually the case. In Paris the gas pipes must be seen for their whole length, and where passing through a floor or partition they must be let through a larger pipe having both ends open. Lights should not be fixed within 36 inches beneath wood-work. The solar or sun light is one of the modern additions for lighting large halls, as well as for dwellingrooms; the globe lights, and some others of the same kind, all assist also in ventilating the apartments by tubes carrying off the products of combustion, which tubes are ordinarily fixed in the thickness of the floor; and as the air therein is raised to a very high temperature, great precautions are required to prevent danger by fire to the timbers, and also where the tubes pass through the roof. The effect of continued hot air on wood is little understood by the public generally. The star light, an invention of the late Mr Owen Jones, consists of a number of jets placed either horizontally or slightly inclining upwards at the jets; this is productive of a pleasing and brilliant light. There are many varieties of gas burners, such as the one called a fish tail, from which the form of the flame is the worst as regards economical results; the bat’s-wing is better, and the argand is the best. The latter is a metal ring, pierced with numerous small holes, which divide the flame and allow of the proper combustion of the gas. Besides the common metal burners, there are some made with a soapstone or other cap, to prevent corrosion; and one of the better class is Bronner’s patent burner, into which the gas is admitted through a very small opening adapted for supplying only a certain quantity of gas per hour. The usual burners have a large opening up to where the gas is consumed, and hence a waste of it.

For publications relating to the smith and founder’s trade, see the article Iron; also Brandon, Analysis of Gothic Architecture, 4to, 1847; Viollet-le-Duc, Diet. Bais., s.v. Grille and Serrurerie; Wyatt, Metal Work, fol., 1852; Jousse, La fidèle ouverture de Tart du Serrurerie, fol., 1627; L'Art dit Serrurerie, in Description des arts et metiers, fol., 1767; Fordrin, Livre du Serrurerie, fol., 1723; Cottingham, Smith, Founder's, A∙c., Directorate, 1823; Pugin, Designs for Iron and Brass Work, 4to, 1835; Shaw, Examples of Ornamental MetalWork, 4to, 1825; Welldon, The Smith’s Eight Hand, 8vo, 1765; Leconte, Choix de nouveaux modèles de Serrurerie, fol., 1838; Scott, Ornamental Designs, fol., 1852; King, Orfeυrerie et ouvrages au moyen age, fol., 1853-60; Tijou, A Neτo Booke of Drawings, fol., 1693; Bordeaux, Serrurerie du moyen age, 4to, 1858; Bury et Hoyau, Modèles de Serrurerie, fol., 1826; Thiollet, Modèles, <kc., fol., no date; Lachave, Balcons, &c., fol., 1864; Normand, Oeuvres, <Lc., fol., 1824.

Hoüse-Painting.

The real object of painting is to protect wood, metals, and stuccoes from the action of the atmosphere, by covering them with a material which is capable of resisting it. A continued succession of moisture and dryness, and of heat and frost, soon effects the decomposition of woods, causes oxidation in most of the metals used for economic purposes, and destroys the generality of stuccoes if their surfaces be exposed nakedly to it. A solution of ceruse or white lead in linseed oil spread over them prevents these injuries in a great measure, and for a considerable period of time; and as the application of such an unction can be repeated without much trouble or expense as often as occasion may require, it may be said to furnish a protection against the contingencies named. In addition to the utility of painting, it is also available as an ornament, by bringing disagreeably or diversely coloured surfaces to a pleasing and uniform tint, or by diversifying a disagreeable monotony of tint, to suit the taste and fancy; and this is done in a great measure by the addition of various pigments to the solution before mentioned.

The painter works with brushes of various sizes, made of hog’s bristles, or of hair with a mixture of bristles, and pencils made of badger’s hair; these, with the addition of pots to hold his colours, a grinding-stone and grinder or muller for grinding or triturating them, a pallet and a pallet knife, dusting brushes and a scraping knife for cleaning iron-work before repainting, are almost his only implements. In painting the outside of windows he sometimes uses the glazier’s horse. His materials are comparatively few also; but for some purposes these require a great variety of ingredients, the preparation and combination of which, however, now devolves principally on the manufacturer or colourman, and not on the painter himself. The colours are ground with a muller, which is worked on the stone until they become a very fine powder; with some, the more they are ground the better is the colour. The powder is moistened with a little water or oil, as necessary, from time to time. They should all be ground separately; it is not good to produce a tint by mixture until they are well prepared. Only the quantities necessary for the work undertaken should be got ready. Common colours are those which are produced by the addition to white lead (or zinc white) and oil of lamp-black, red lead, or any of the common ochres; blues, greens, rich reds, pinks, and yellows, &c., being more costly, are taken as such. Unflatted white is a common colour; flatted it classes with the rich colours. If the same surface be painted of two different tints, it is said to be in party colours. The substance generally constituting nine-tenths of the body of paint is carbonate of lead, commonly called white lead, the quality of which is therefore of the greatest importance to the durability of the work. It is said to improve by being kept for several years before use. Three qualities are manufactured, and there are six or more chief modes of adulteration recorded, which accounts in some measure for the great difference in painters’ prices, and the relative values of their work when done. The other metallic white paint occasionally used, especially in water colour painting, is zinc white. It is well known for its intense whiteness, its resistance to sulphurous and other deteriorating causes, and its harmless qualities to the workman and the inmates of the house under decoration. Zinc white possesses less body than white lead, and great care is requisite that the colour when ground in oil is of sufficient consistence to be laid on a flat surface without showing through; any oil in excess will form a slight glutinous coating on the surface, retaining every particle of dust brought in contact with it, until it has evaporated. In general this white does not dry so quickly as the other colour, but this defect is remedied by the application of proper drying oils. It is asserted that in consequence of the great durability of the colour, the paint may be washed for a succession of three, four, and even five years; and that after each successive washing the surface will be found as clear and bright as when fresh painted.

In painting or laying on the colour, the brush must be constantly at right angles to the face of the work, only the ends of the hairs, in fact, touching it, for in this manner the paint is at the same time forced into the pores of the wood and distributed equally over the surface. If the brush be held obliquely to the work, it will leave the paint in thick masses wherever it is first applied after being dipped for a fresh supply into the pot, and the surface will be daubed, but not painted. Painting, when properly executed, will not present a shining, smooth, and glossy appearance, as if it formed a film or skin, but will show a fine and regular grain, as if the surface were natural, or had received a mere stain without destroying the original texture. Imitative grainings, however, and the varnishes which are intended to protect them, and make them bear out, necessarily produce a new and artificial texture; and for this reason some consider them to a greater or less extent disagreeable, however well the imitations may be effected. Carved mouldings and other enrichments have to be picked out with a pencil or small brush, that the quirks, <fcc., be not choked up.

As it must be presumed that all the wood submitted to the operations of a painter, which has passed through the hands of the joiner, is already well seasoned and properly dry, it is only necessary to say generally, that the work should be free from moisture of any and every kind before paint is applied to it, or it will at the least prove useless, and probably injurious rather than beneficial. This remark applies alike to wood and to plastered work, both internal and external; that is, whether they be subjected to the more violent changes of the weather or not. Dampness or moisture in woods, stopped in or covered up with paint, will, under ordinary circumstances, tend to their destruction; and in stuccoes it will spoil the paint, and most probably injure the plastering itself also. The first thing the workman has to attend to in painting new wood-work is to prepare its surface for the reception of paint, by counteracting the effect of anything that may tend to prevent it from becoming identified with the material. Thus, in painting pine-wpods, the resin in the knots which appear on the surface must be neutralized, or a blemish will appear in the finished work over every resinous part. In best work the knots should be cut out to a slight depth at the bench, and the holes filled up with a stiff putty made of white lead, japan, and turpentine. The next best way is to cover them with gold or silver leaf. The usual method is to cover them with a size knotting, which is a preparation of red lead, white lead, and whitening made into a thin paste with size. The common coating of red ochre is worth nothing. The next process is that of priming, which consists in giving a coat of white lead with red lead and a little drier in linseed oil. This is the first coat, upon which the look of the finished work much depends. Inequalities or unevennesses of surface must be reduced with sand-paper or pumice-stone, or made up with putty. The necessary process for killing knots will generally leave a film, which must be rubbed down; and the heads of nails and brads having been punched in, will present indentations, which should be stopped, as well as any cracks or other imperfections, with putty. A second coat is then given, consisting of white lead and linseed oil. It should have a good body, and be laid even. This coat, when thoroughly dry, is in best work rubbed down with fine sand paper and carefully examined to ascertain if any further stopping be required; and then the third coat or ground colour is applied, of a somewhat darker tint than wanted when finished, having sufficient oil for easy working, but not too fluid,—about two-thirds oil and one-third turpentine are used. The flatting coat follows, the object of which is to do away with the gloss or glaze of the oil, by obtaining a flat appearance. White lead is mixed with turpentine, with sometimes a little copal varnish; the colouring matter is added, but always lighter than the ground colour, or it would when finished appear in a series of shades and stripes. Flatting must be executed quickly, on account of the evaporation of the turpentine, and the brush is generally, if not always, carried up the wall and not across it. Some painters use a large quantity of turpentine in the several coats for quick work, as it dries more rapidly; but for good and lasting work no turpentine should be used. Flatted work is generally done only to best apartments, chief staircases, entrance halls, &c., and omitted in the upper rooms, in bedrooms, and in basements. All new wood-work should be painted a sufficient number of coats to “bear out” as it is called; this is a precaution against each coat being so much diluted with turpentine or other fluid as not to cover sufficiently, which is seen by a deadness in one part and a glaze in another. The priming coat and three others should be sufficient. Sometimes plaster and new wood are first done over with clearcole, which is white lead ground up in water and size added. This prevents absorption of the oil, but the paint added subsequently is apt to blister or to crack off; it therefore should not be allowed.

Plaster and stucco to be painted requires some care in the workmanship of it, as noticed under “Plaster-work,” sτιpra, to prevent bubbles, and must be quite dry. Some persons recommend a priming or a second coat of strong double size; the next coat then consists of white lead in oil as stiff as possible, and then another coat of size, and so on; but such work should be repudiated. A good first coat of priming, as much as the stucco will absorb, is essential.

All new outside work should be primed with red lead or litharge, mixed in linseed oil; the second coat is of the same mixture if four-coat work is to be done, and in this coat all defects are to be made good; the third and fourth coats, as may be determined upon, are generally of the tint required.

In painting old work, where two coats are generally considered sufficient, the surface must be well washed to get rid of all dirt and grease, and then rubbed down with pumice-stone to remove all inequalities. The work then receives one coat, after which any holes are stopped by the painter with putty; the second and perhaps a third coat, or a flatting coat, are then applied. Sometimes each of the earlier coats is rubbed down.

Old ceilings and soffits of stairs are either washed to clean off the dirt and grease, stopped (which is cutting out the cracks and stopping them with new plaster), and whitened by a coat of whitening or Spanish white mixed with size; or after the two first operations they are finished in distemper, which is white lead and size; it presents a better appearance. Colouring is also done to plastered walls, the white being mixed in half linseed oil and half turpentine, and some earth added to make the tint required. Limewhiting is done by the bricklayer’s labourer. Stucco or plaster-work, which is intended to be painted, but which is not sufficiently dry to receive the oil, may have a coating of water colours, or distemper colour, as it is called, in order to give a more finished appearance to that part of the building. The colour selected should be grouud very fine, and incorporated with the whiting and parchment, or other strong size. Two coats will be required to make it bear out uniformly. When the stucco is sufficiently dry, and it is desired to be painted, the whole of the above colouring has to be washed off, and the painting proceeded with as described for new work.

Metal-work, not being absorbent, only requires when new to have a priming, and one, two, or three coats of oil paints, as may be considered necessary. It should have a coat as soon after it leaves the founder or smith as possible, to prevent early stages of oxidation. Old w ork should be cleaned, scraped, and filed if necessary, to remove rust, broken paint, and dirt.

Graining is understood among painters to be the imitating of the several different species of ornamental woods, as satin-wood, rose-wood, king-wood, air-wood, mahogany, wainscot or oak, and others. After the necessary coats of paint have been put on to the wood, a ground is then laid of Naples yellow and ceruse, diluted with turpentine if for satin-wood, which is left to dry. The painter then prepares small quantities of the same yellow and ochre with a little brown, and boiled oil and turpentine, and having mixed this, spreads it over some small part of his work. The flat hog’s hair brushes being dipped in the liquid and drawn down the newly laid colour, the shades and grainings are produced. To obtain the mottled appearance, the camel’s hair pencils are applied, and when completed the work is left to dry, and afterwards covered by a coat or two of good copal varnish. Imitation wainscot requires the use of combs of various degrees of fineness to obtain the grain (whence the process is called combing by some persons), and the flower is got by wiping off the colour with a piece of rag. When dry it is over-grained to obtain a more complete representation of the natural wood, and then varnished. If the work be done in water colour and not in oil, beer grounds to act as a drier are mixed with the colour; this sets it ready for varnishing. A “patent graining-machine,” a sort of roller with a pattern upon it, has lately been introduced. The writer of this article suggested some years ago that deal well sized to prevent absorption might be at once grained either wainscot or pollard oak, without the preliminary operation, delay, and smell of painting. When dry it is to be varnished as usual. The effect is somewhat better than that obtained by the usual method of graining.

Marbling is the imitation of real marbles, granites, &c., some of which are represented by splashing on the carefully prepared ground, which should have been painted and often rubbed and polished to obtain an even surface; others have to be painted in colours, and then well varnished. The most expert at this sort of imitation do their work so as to prevent its easy detection except by the touch.

Ornamental painting embraces the execution of friezes and the decorative parts of architecture on walls and ceilings in chiaroscuro (or light and shade) or monochrome colouring. The ground is well prepared, and of the tint of the proposed work; the ornament and figures are drawn upon it, and are then painted and shaded to give them their due effect. This kind of work is sometimes painted on cloth and then fastened up. When the ornamental work is of a similar pattern throughout, as mouldings, fretwork, a running ornament, <fcc., it is effected by stencilling. This method consists in drawing a certain length of the pattern on paper, which is pricked through with a large sized needle, then laid on the wall to be ornamented, and struck with a small linen bag containing powdered chalk; the chalk enters the apertures, and fixes itself against the paint. The painter then draws it, or fills in the pattern with colours. Another method is to cut out the pattern where possible, and the paper, being stiffened with size, is laid on the surface, and a brush filled with the colour passed over it; the paper is carefully removed and laid on a fresh place, and so on. The pattern may then be touched up when dry with another tint, or with gold, or another pattern with minuter detail laid on it, and the operation repeated. A wall surface may be covered with such an ornamentation, of which paper hangings are a cheap substitute.

Many of these methods of decoration having been styled shams, the promoters of real woods advocated the disuse of paints, <fcc. This has led to the increased use of deals and pines for inside doors, wainscots, linings, shutters, and the like, which, if not left as completed by the tradesmen, are sized and varnished or polished. But in such a case a good selection of the wood is necessary, and it has to be picked. Another method is to stain the timber, as of roofs, galleries, and the like, or the joiners’ work, so that it represents various tints of oak, and this is protected by a coat or two of varnish. These systems are open to the objection that the varnish, especially in towns, darkens rapidly, and every coat of it adds to the defect, so that in a few years paint is required to give the work the cleau and lively appearance the wood originally possessed. Real wainscot, mahogany, and other woods are usually polished; the first is sometimes varnished after being properly prepared to prevent the rise of the grain which occurs when it is touched by a liquid.

Varnishing having been frequently referred to, we must notice that there are many varieties useful for various purposes. Like white lead, oil, and turpentine, they are subject to much adulteration, whereby the work is deprived of its proper consistency, and the painter and his employer dissatisfied with the result. There are drying varnishes made with spirit of wine; these are applied to some furniture, mouldings, &c. Varnishes made with essential oils, especially those made with oil of turpentine or ether and pure copal, are very solid, and better than those made with fat drying oils, which, from their colour being dark, are used only with grounds of a dark colour. Varnish can sometimes be tinted to correct defects of colour in graining, &c. For wood-work copal varnish in oil should alone be used.

It is not within our province to enter upon the higher class of painting on walls, which comes under the trade of the decorator, including that of the gilder and the artistic draughtsman and colourist, nor upon the higher class of paper-hangings. Decorations must necessarily depend upon the taste and skill required or employed in producing them. Paper-hangings are paid for by the piece or yard, a piece being made in England twelve yards long and twenty inches wide, and the hanging is charged at so much the piece. A dozen of borders is twelve yards long; they are charged by the yard for the material, and by the dozen for hanging. Sizing and otherwise preparing the walls may be requisite before hanging the papers; and washing old papers from off the walls should always be insisted upon by the owner of a house, as accumulations of paste, colours, and size are apt to breed vermin, and, as some think, to give rise to fevers. French paper-hangings are only eighteen inches wide and nine yards long. Wood-linings, old panelled wainscoting, and other irregular surfaces, require to be canvased and papered before the decorative paper is hung, otherwise it is liable to crack with the shrinking of the wood.

The principal publications on house painting are as follows: —Tingry, Painter's and Varnisher's Guide, 8vo, 1832, 3d edit.; Higgins, Painter's and Decorator's Companion, 4to, 1841; Arrowsmith, House Decorator's and Painter's Guide, 4to, 1840; Field, Rudiments of the Painter's Art, 12mo, 1850, and his Chromatography, 4to, 1841; Smith, The Art of House Painting, 12mo, 1687, improved by W. Butcher, 8vo, 1821; Whittock, Decorative Painter's Guide, 4to, 1841; Moxon, Grainer's Guide, 1842; Barber, Painter's Assistant, 12mo, 1852; Wood and Marble Imitator's Manual, 8vo, Edinb. There are two or three French journals which give examples of imitations of woods and marbles, and illustrations of decorations for apartments. (w. P.) [table]