The grooves of the soundboard are spaces left between wooden bars glued on to the table of the soundboard. There is usually one groove for every key. The grooves of the bass notes, which have to supply wind for large pipes, are broader than those of the treble. The bass bars are also thicker than those of the treble, that they may the better support the great weight which rests on the bass portion of the soundboard. The table forms the top of the grooves. The grooves are generally-closed below with leather, except the opening left in each, which is closed by the key-valve or pallet.

The sliders are connected with the draw-stops or stophandles, which are covered in with stout upper boards, on which the pipes stand. The stophandles are pulled out, and holes are then bored straight down through the upper boards, sliders, and table to admit the wind from the grooves to the pipes. When the sliders are shifted by pushing in the handles, the holes no longer correspond, and the pipes are silenced.

Pipes are divided first into flue-pipes and reed-pipes. Flue-pipes are blown by a wind mouthpiece characteristic of the organ, while in reed-pipes the wind acts on a metal tongue vibrating on a reed, and the motion of the tongue determines the speech of the pipe.

Pipes are made either of wood or of metal. Wood flue-pipes are generally of the form of a rectangular parallelepiped, metal fluepipes of a cylindrical shape. Reed-pipes are conical or pyramidal, and widen towards the top. Some flue-pipes are made with stopped ends; these as a rule sound a note about an octave lower than the corresponding open pipes of the same length. Such are the stopped diapason, bourdon, and stopped flute.

The general elementary theory of the resonance of a pipe is tolerably simple. The effective length of the pipe is determined by measuring from the upper lip to the open end in open pipes, and from the upper lip to the stopper and back again in stopped pipes. To this is added an allowance for the effect of each opening, since the condition of perfect freedom from constraint does not subsist at the opening itself. The corrected length is traversed twice (backwards and forwards) by sound, in the time of one vibration of the resultant note. This describes in a rough and general manner the way in which any disturbance gives rise to the note of the pipe; but the theory of the mouthpieces is a much more difficult matter, into which we cannot here enter.

In reed-pipes which are simply conical the resonance of the body is nearly the same as that of an open pipe of the same length. Where the form is irregular no simple rule can be given. But the resonance of the body of the pipe is generally the same as the note produced. The tongue of a reed-pipe alternately opens and closes the aperture of the reed. In this way it admits pulses of wind to the body of the pipe; these, if they recur at the proper intervals, maintain its vibration, which takes place when the note produced corresponds to the resonance of the pipe. The reed itself has its vibrating length determined by a wire which presses against it. The free end of this wire is touched with the tuning tool until a satisfactory note is produced.

The pitch of the different stops is commonly denoted by the conventional approximate length of the pipe sounded by C, the lowest key of the manual. Even in incomplete stops which have no bass, the length of the pipe which C would have if the stop were extended down serves to indicate the pitch.

The conventional length of the C-pipe for stops having the normal pitch of the keys is 8 feet; a pipe having twice this length sounds the octave below, a pipe having half that length the octave above, and so on. Thus stops which sound the octave below the normal pitch of the keys are spoken of as 16-foot stops. Even where the pipes are stopped so that the actual length is only 8 feet, they are spoken of as having “16-foot tone.” Similarly 32-foot stops sound two octaves below the normal pitch of the keys. But if these notes are produced by stopped pipes, whose actual length is only 16 feet, they are spoken of as having “32-foot tone.” Sixteen-foot and 32-foot stops are specially characteristic of the pedal, where the names also signify the length of the open pipe which would sound the note actually produced by the lowest C. In old organs, where the modern compass was not adopted, it was not unusual to find stops spoken of as of 12 feet or of 24 feet. In these cases the lowest note was frequently F. Old English organs, however, more often had G for their lowest note. The designation of the stops in these cases had become rather anomalous, and need not be entered into. Of stops higher than the normal pitch of the keys, the octave is denoted by 4 feet if made with open pipes, 4-foot tone if stopped; the twelfth is commonly spoken of as 2f, the fifteenth or double octave as 2 feet. Higher-sounding stops are occasionally used, but these generally form part of “mixtures,” and the foot-lengths of the separate ranks are not usually given.

The true or accurate lengths of the pipes vary within considerable limits. The base of the scales (dimensions) varies according to the standard of pitch, and the voicing and the complicated natural laws of pipes produce other deviations from simple relations, so that the conventional dimensions can only be regarded as a simple means of classifying the stops according to their pitch-relations. For this purpose they are essential; they are continually appealed to in discussion and description; and they are almost invariably marked on the stop-handles in all countries, so that a moderate knowledge of foreign nomenclatures, combined with the habit of seizing the meaning of the figures such as 16, 8, 4, on the stop-handles, will frequently suffice as a key to the complexities of a foreign organ.

Each of the manuals, or rows of keys, of an organ constitutes a separate organ, which is more or less complete in itself. The names of the different manuals or organs are great organ, swell organ, choir organ, and solo organ. The fifth manual, where it occurs, is the echo organ. The above is the usual order in point of development and frequency of occurrence, although the solo is sometimes preferred to the choir organ. The great organ is in a certain sense the principal department of the organ. It may be regarded as formed by a completely developed series of those fundamental stops which constitute the solid basis of the tone of the instrument. If an instrument be constructed with only a single manual this necessarily assumes, in general, the characteristics of a great organ. The great organ is called “grande orgue” in French, and first manual or “haupt-werk” in German.

It is proposed to describe the principal organ-stops under the heads of the manuals to which they belong. The enumeration will not be exhaustive, but will include all the usual types.

The great organ commences generally with stops of 16-foot length or tone in large instruments. In some cases a 32-foot sounding stop is introduced, but this cannot be said to be a proper characteristic of the great organ. The foundation tone is of 8 feet; the stops of higher pitch serve to add brilliancy; those of 16 feet, which sound the octave below the normal pitch, serve to add gravity and weight to the tone. Sixteen-foot stops are commonly spoken of as “doubles,” their conventional length being twice that of stops of normal pitch.

The 16-foot stops are the 16 double open diapason, and the 16 bourdon or double stopped diapason, to which, in very large instruments, there may be added a 16 double trumpet. The double open diapason on the great organ consists usually of metal pipes, having moderate “scale” or transverse dimensions. These are of the same general character as the pipes of the ordinary open diapason, though they are made somewhat less powerful. In the better instruments of the second class as to size this stop alone would probably be regarded as representing suitably and sufficiently the class of doubles on the great organ. It gives great body to the general tone, and appears decidedly preferable to the bourdon, which frequently takes its place. The 16 double dulciana may be regarded as a variation of the double open diapason. It is sometimes used where the full effect of a double open is not considered desirable. It possesses the light and not full tone of the dulciana. It does not appear to be peculiarly suitable for the purposes of a double.

The 16 bourdon or double stopped diapason, when used on the great organ, is made of rather small scale and light tone. It gives great body to a large great organ, and affords interesting combinations with other stops, such as the 4-foot flute. It is used either alone in smaller organs of the second class or in addition to a double open in larger instruments. The notes are produced from wooden pipes of rectangular section, stopped at the end, and having half the conventional length,

The 16 double trumpet is a trumpet (large reed stop) sounding the octave below the normal pitch. It is used generally in instruments of the largest size, but is somewhat more common in Germany. It is useful in giving a massive character to the tone of the full great organ, which is otherwise apt to become disagreeable on account of the great development of stops of a piercing character. If, however, the double trumpet is rough in tone, it is apt to communicate to the whole a corresponding impression.

The judicious balancing of such elements as the double trumpet and the piercing stops such as mixtures is one of the principal features of a good German great organ.

We now proceed to the 8-foot stops (the reeds come at the end according to ordinary usage). An ordinary great organ may contain 8 stopped diapason, 8 open diapason (one or more), 8 gamba, and 8 hohlflöte. The 8 stopped diapason on the great organ is usually of wood, of moderate scale, and some considerable fulness of tone. The actual lengths are about half the conventional lengths. These pipes are sometimes made of metal. Few stops admit of more variety and individuality in their quality of tone than the stopped diapason; but too frequently the great organ stopped diapason fails to attract attention on its merits, being regarded simply as an inconsiderable portion of the foundation tone.

If there is any one stop which in itself represents the organ as a whole it is the open diapason. The pipes of this stop are the typical metal pipes which have always been characteristic of the appearance of the organ. A single open diapason stop is capable of being used as an organ of sufficient power for many purposes, though of course without variety. The pipes of this stop are called “principal” in German, this appellation apparently corresponding to the fact that they are the true and original organ-pipes. The English appellation of “diapason” has been taken to mean that these are the normal pipes which run through the whole compass. This, however, does not appear to be the actual derivation of the term; originally it is technically applied to the organ-builder’s rule, which gives the dimensions of pipes; and it appears that the application to the stop followed on this meaning.

The scales, character, and voicing of the open diapason vary with fashion, and are different in different countries. We may distinguish three principal types. The old English diapasons of the days before the introduction of pedal organs into England were characterized by a rich sweet tone, and were not very powerful. They were generally voiced on a light wind, having a pressure equivalent to that of a column of water of from 2 to 2∣ inches. The scale was in some cases very large, as in Green’s two open diapasons in the old organ at St George’s, Windsor; in these the wind was light and the tone very soft. In other cases the scale was smaller and the voicing bolder, as in Father Smith’s original diapasons in St Paul’s Cathedral. But on the whole the old English diapasons presented a lovely quality of tone. English travellers of those days, accustomed to these diapasons, usually found foreign organs harsh, noisy, and uninteresting. And there are many still in England who, while recognizing the necessity of a firmer diapason tone in view of the introduction of the heavy pedal bass, and the corresponding strengthening of the upper departments of the organ tone, lament the disappearance of the old diapason tone. However, it is possible with care to obtain diapasons presenting the sweet characteristics of the old English tone, combined with sufficient fulness and power to form a sound general foundation. And there can be no doubt that this should be one of the chief points to be kept in view in organ design.

The German diapason was of an entirely different character from the English. The heavy bass of the pedals has been an essential characteristic of the German organ for at least two or three centuries, or, as it is said, for four. The development of the piercing stops of high pitch was equally general. Thus foundation work of comparatively great power was required to maintain the balance of tone; the ordinary German diapason was very loud, and we may almost say coarse, in its tone when compared with the old English diapason. The German stop was voiced as a rule on from 3 J to 4 inches of wind, not quite twice the pressure used in England.

The French diapason is a modern variety. It may be described as presenting rather the characteristics of a loud gamba than of a diapason. In other words, the tone tends towards a certain quality which may be described as “tinny” or metallic, or as approaching to that of a string instrument of rather coarse character. Some modern English builders appear to aim at the same model, and not without success.

The tone of a diapason must be strong enough to assert itself. It is the foundation of the whole organ tone. It is the voicer’s business to satisfy this condition in conjunction with the requirement that the tone shall be full and of agreeable quality.

The 8 spitzflöte may be regarded as a variety of open diapason. The pipes taper slightly towards the top, and the quality is slightly stringy. This stop was much used at one time in place of a second open diapason. But it appears better that, where two open diapasons are desirable, they should both be of full diapason quality, though possibly of different strengths and dimensions. The admixture of stringy qualities of tone with the diapasons is always to be deprecated.

The 8 gamba was originally an imitation of the viola da gamba, a sort of violoncello. When made of a light quality of tone it is a pleasing stop; but its use in the great organ instead of a second open diapason is greatly to be deprecated for the reasons just stated. It is frequently found that, where a gamba is provided on the great organ, it is necessary to remove it from the compositions (mechanical arrangements for pulling out the stop-handles in different combinations), as the tone does not blend.

The 8 hohlflöte is an open flute, usually of wood, and of small scale. If made to a moderate scale and fully voiced it possesses a full pleasant tone, which is a useful support to the foundation tone of the great organ. The 8 clarabella differs from the hohlflöte in being usually of rather large scale, and having the open pipes only in the treble. In old organs a separate bass was generally provided; now it is more usual to supply the stop with a stopped bass. The dulciana and keraulophon, though sometimes found on the great organ, are regarded as more appropriately placed elsewhere.

The 4-foot stops of the great organ comprise the 4 principal and the 4 flute. The 4 principal is the octave of the open diapason, generally of somewhat reduced scale and light but bright quality of tone. The use of the word “principal” in connexion with this stop is purely English, and is said to be connected with the use made of it as the standard of tuning for the whole organ. The Germans and French both designate this stop as “octave.”

Of the 4 flute there are several varieties,—open, stopped, wood, metal, and harmonic. The harmonic flute has open metal pipes of double the conventional length, which speak their octave. This is determined partly by the voicing, partly by making a small hole about the middle of the length, which determines the motion as that of the two separate lengths between which the hole lies. Harmonic flutes have a sweet but full and powerful tone. Other flutes are generally rather light, except the waldflöte, which is a powerful stop of a somewhat hooting quality.

The great organ flute is frequently used to give brilliancy to light combinations. Thus it may be used with the stopped diapason alone, or with the 16 bourdon alone, or with any of these and either or both of the open diapasons. Where the diapasons are scarcely strong enough to assert themselves in accompaniment, it is a very common practice to put the 4 flute into the diapason composition.

If any such use is made of the flute it is desirable that it should not be too strong; but its habitual use to give point to the diapasons is in every way to be deprecated. If the diapasons are not strong enough, let them be altered; but that...

The grooves of the soundboard are spaces left between wooden bars glued on to the table of the soundboard. There is usually one groove for every key. The grooves of the bass notes, which have to supply wind for large pipes, are broader than those of the treble. The bass bars are also thicker than those of the treble, that they may the better support the great weight which rests on the bass portion of the soundboard. The table forms the top of the grooves. The grooves are generally-closed below with leather, except the opening left in each, which is closed by the key-valve or pallet.

The sliders are connected with the draw-stops or stophandles, which are covered in with stout upper boards, on which the pipes stand. The stophandles are pulled out, and holes are then bored straight down through the upper boards, sliders, and table to admit the wind from the grooves to the pipes. When the sliders are shifted by pushing in the handles, the holes no longer correspond, and the pipes are silenced.

Pipes are divided first into flue-pipes and reed-pipes. Flue-pipes are blown by a wind mouthpiece characteristic of the organ, while in reed-pipes the wind acts on a metal tongue vibrating on a reed, and the motion of the tongue determines the speech of the pipe.

Pipes are made either of wood or of metal. Wood flue-pipes are generally of the form of a rectangular parallelepiped, metal fluepipes of a cylindrical shape. Reed-pipes are conical or pyramidal, and widen towards the top. Some flue-pipes are made with stopped ends; these as a rule sound a note about an octave lower than the corresponding open pipes of the same length. Such are the stopped diapason, bourdon, and stopped flute.

The general elementary theory of the resonance of a pipe is tolerably simple. The effective length of the pipe is determined by measuring from the upper lip to the open end in open pipes, and from the upper lip to the stopper and back again in stopped pipes. To this is added an allowance for the effect of each opening, since the condition of perfect freedom from constraint does not subsist at the opening itself. The corrected length is traversed twice (backwards and forwards) by sound, in the time of one vibration of the resultant note. This describes in a rough and general manner the way in which any disturbance gives rise to the note of the pipe; but the theory of the mouthpieces is a much more difficult matter, into which we cannot here enter.

In reed-pipes which are simply conical the resonance of the body is nearly the same as that of an open pipe of the same length. Where the form is irregular no simple rule can be given. But the resonance of the body of the pipe is generally the same as the note produced. The tongue of a reed-pipe alternately opens and closes the aperture of the reed. In this way it admits pulses of wind to the body of the pipe; these, if they recur at the proper intervals, maintain its vibration, which takes place when the note produced corresponds to the resonance of the pipe. The reed itself has its vibrating length determined by a wire which presses against it. The free end of this wire is touched with the tuning tool until a satisfactory note is produced.

The pitch of the different stops is commonly denoted by the conventional approximate length of the pipe sounded by C, the lowest key of the manual. Even in incomplete stops which have no bass, the length of the pipe which C would have if the stop were extended down serves to indicate the pitch.

The conventional length of the C-pipe for stops having the normal pitch of the keys is 8 feet; a pipe having twice this length sounds the octave below, a pipe having half that length the octave above, and so on. Thus stops which sound the octave below the normal pitch of the keys are spoken of as 16-foot stops. Even where the pipes are stopped so that the actual length is only 8 feet, they are spoken of as having “16-foot tone.” Similarly 32-foot stops sound two octaves below the normal pitch of the keys. But if these notes are produced by stopped pipes, whose actual length is only 16 feet, they are spoken of as having “32-foot tone.” Sixteen-foot and 32-foot stops are specially characteristic of the pedal, where the names also signify the length of the open pipe which would sound the note actually produced by the lowest C. In old organs, where the modern compass was not adopted, it was not unusual to find stops spoken of as of 12 feet or of 24 feet. In these cases the lowest note was frequently F. Old English organs, however, more often had G for their lowest note. The designation of the stops in these cases had become rather anomalous, and need not be entered into. Of stops higher than the normal pitch of the keys, the octave is denoted by 4 feet if made with open pipes, 4-foot tone if stopped; the twelfth is commonly spoken of as 2f, the fifteenth or double octave as 2 feet. Higher-sounding stops are occasionally used, but these generally form part of “mixtures,” and the foot-lengths of the separate ranks are not usually given.

The true or accurate lengths of the pipes vary within considerable limits. The base of the scales (dimensions) varies according to the standard of pitch, and the voicing and the complicated natural laws of pipes produce other deviations from simple relations, so that the conventional dimensions can only be regarded as a simple means of classifying the stops according to their pitch-relations. For this purpose they are essential; they are continually appealed to in discussion and description; and they are almost invariably marked on the stop-handles in all countries, so that a moderate knowledge of foreign nomenclatures, combined with the habit of seizing the meaning of the figures such as 16, 8, 4, on the stop-handles, will frequently suffice as a key to the complexities of a foreign organ.

Each of the manuals, or rows of keys, of an organ constitutes a separate organ, which is more or less complete in itself. The names of the different manuals or organs are great organ, swell organ, choir organ, and solo organ. The fifth manual, where it occurs, is the echo organ. The above is the usual order in point of development and frequency of occurrence, although the solo is sometimes preferred to the choir organ. The great organ is in a certain sense the principal department of the organ. It may be regarded as formed by a completely developed series of those fundamental stops which constitute the solid basis of the tone of the instrument. If an instrument be constructed with only a single manual this necessarily assumes, in general, the characteristics of a great organ. The great organ is called “grande orgue” in French, and first manual or “haupt-werk” in German.

It is proposed to describe the principal organ-stops under the heads of the manuals to which they belong. The enumeration will not be exhaustive, but will include all the usual types.

The great organ commences generally with stops of 16-foot length or tone in large instruments. In some cases a 32-foot sounding stop is introduced, but this cannot be said to be a proper characteristic of the great organ. The foundation tone is of 8 feet; the stops of higher pitch serve to add brilliancy; those of 16 feet, which sound the octave below the normal pitch, serve to add gravity and weight to the tone. Sixteen-foot stops are commonly spoken of as “doubles,” their conventional length being twice that of stops of normal pitch.

The 16-foot stops are the 16 double open diapason, and the 16 bourdon or double stopped diapason, to which, in very large instruments, there may be added a 16 double trumpet. The double open diapason on the great organ consists usually of metal pipes, having moderate “scale” or transverse dimensions. These are of the same general character as the pipes of the ordinary open diapason, though they are made somewhat less powerful. In the better instruments of the second class as to size this stop alone would probably be regarded as representing suitably and sufficiently the class of doubles on the great organ. It gives great body to the general tone, and appears decidedly preferable to the bourdon, which frequently takes its place. The 16 double dulciana may be regarded as a variation of the double open diapason. It is sometimes used where the full effect of a double open is not considered desirable. It possesses the light and not full tone of the dulciana. It does not appear to be peculiarly suitable for the purposes of a double.

The 16 bourdon or double stopped diapason, when used on the great organ, is made of rather small scale and light tone. It gives great body to a large great organ, and affords interesting combinations with other stops, such as the 4-foot flute. It is used either alone in smaller organs of the second class or in addition to a double open in larger instruments. The notes are produced from wooden pipes of rectangular section, stopped at the end, and having half the conventional length,

The 16 double trumpet is a trumpet (large reed stop) sounding the octave below the normal pitch. It is used generally in instruments of the largest size, but is somewhat more common in Germany. It is useful in giving a massive character to the tone of the full great organ, which is otherwise apt to become disagreeable on account of the great development of stops of a piercing character. If, however, the double trumpet is rough in tone, it is apt to communicate to the whole a corresponding impression.

The judicious balancing of such elements as the double trumpet and the piercing stops such as mixtures is one of the principal features of a good German great organ.

We now proceed to the 8-foot stops (the reeds come at the end according to ordinary usage). An ordinary great organ may contain 8 stopped diapason, 8 open diapason (one or more), 8 gamba, and 8 hohlflöte. The 8 stopped diapason on the great organ is usually of wood, of moderate scale, and some considerable fulness of tone. The actual lengths are about half the conventional lengths. These pipes are sometimes made of metal. Few stops admit of more variety and individuality in their quality of tone than the stopped diapason; but too frequently the great organ stopped diapason fails to attract attention on its merits, being regarded simply as an inconsiderable portion of the foundation tone.

If there is any one stop which in itself represents the organ as a whole it is the open diapason. The pipes of this stop are the typical metal pipes which have always been characteristic of the appearance of the organ. A single open diapason stop is capable of being used as an organ of sufficient power for many purposes, though of course without variety. The pipes of this stop are called “principal” in German, this appellation apparently corresponding to the fact that they are the true and original organ-pipes. The English appellation of “diapason” has been taken to mean that these are the normal pipes which run through the whole compass. This, however, does not appear to be the actual derivation of the term; originally it is technically applied to the organ-builder’s rule, which gives the dimensions of pipes; and it appears that the application to the stop followed on this meaning.

The scales, character, and voicing of the open diapason vary with fashion, and are different in different countries. We may distinguish three principal types. The old English diapasons of the days before the introduction of pedal organs into England were characterized by a rich sweet tone, and were not very powerful. They were generally voiced on a light wind, having a pressure equivalent to that of a column of water of from 2 to 2∣ inches. The scale was in some cases very large, as in Green’s two open diapasons in the old organ at St George’s, Windsor; in these the wind was light and the tone very soft. In other cases the scale was smaller and the voicing bolder, as in Father Smith’s original diapasons in St Paul’s Cathedral. But on the whole the old English diapasons presented a lovely quality of tone. English travellers of those days, accustomed to these diapasons, usually found foreign organs harsh, noisy, and uninteresting. And there are many still in England who, while recognizing the necessity of a firmer diapason tone in view of the introduction of the heavy pedal bass, and the corresponding strengthening of the upper departments of the organ tone, lament the disappearance of the old diapason tone. However, it is possible with care to obtain diapasons presenting the sweet characteristics of the old English tone, combined with sufficient fulness and power to form a sound general foundation. And there can be no doubt that this should be one of the chief points to be kept in view in organ design.

The German diapason was of an entirely different character from the English. The heavy bass of the pedals has been an essential characteristic of the German organ for at least two or three centuries, or, as it is said, for four. The development of the piercing stops of high pitch was equally general. Thus foundation work of comparatively great power was required to maintain the balance of tone; the ordinary German diapason was very loud, and we may almost say coarse, in its tone when compared with the old English diapason. The German stop was voiced as a rule on from 3 J to 4 inches of wind, not quite twice the pressure used in England.

The French diapason is a modern variety. It may be described as presenting rather the characteristics of a loud gamba than of a diapason. In other words, the tone tends towards a certain quality which may be described as “tinny” or metallic, or as approaching to that of a string instrument of rather coarse character. Some modern English builders appear to aim at the same model, and not without success.

The tone of a diapason must be strong enough to assert itself. It is the foundation of the whole organ tone. It is the voicer’s business to satisfy this condition in conjunction with the requirement that the tone shall be full and of agreeable quality.

The 8 spitzflöte may be regarded as a variety of open diapason. The pipes taper slightly towards the top, and the quality is slightly stringy. This stop was much used at one time in place of a second open diapason. But it appears better that, where two open diapasons are desirable, they should both be of full diapason quality, though possibly of different strengths and dimensions. The admixture of stringy qualities of tone with the diapasons is always to be deprecated.

The 8 gamba was originally an imitation of the viola da gamba, a sort of violoncello. When made of a light quality of tone it is a pleasing stop; but its use in the great organ instead of a second open diapason is greatly to be deprecated for the reasons just stated. It is frequently found that, where a gamba is provided on the great organ, it is necessary to remove it from the compositions (mechanical arrangements for pulling out the stop-handles in different combinations), as the tone does not blend.

The 8 hohlflöte is an open flute, usually of wood, and of small scale. If made to a moderate scale and fully voiced it possesses a full pleasant tone, which is a useful support to the foundation tone of the great organ. The 8 clarabella differs from the hohlflöte in being usually of rather large scale, and having the open pipes only in the treble. In old organs a separate bass was generally provided; now it is more usual to supply the stop with a stopped bass. The dulciana and keraulophon, though sometimes found on the great organ, are regarded as more appropriately placed elsewhere.

The 4-foot stops of the great organ comprise the 4 principal and the 4 flute. The 4 principal is the octave of the open diapason, generally of somewhat reduced scale and light but bright quality of tone. The use of the word “principal” in connexion with this stop is purely English, and is said to be connected with the use made of it as the standard of tuning for the whole organ. The Germans and French both designate this stop as “octave.”

Of the 4 flute there are several varieties,—open, stopped, wood, metal, and harmonic. The harmonic flute has open metal pipes of double the conventional length, which speak their octave. This is determined partly by the voicing, partly by making a small hole about the middle of the length, which determines the motion as that of the two separate lengths between which the hole lies. Harmonic flutes have a sweet but full and powerful tone. Other flutes are generally rather light, except the waldflöte, which is a powerful stop of a somewhat hooting quality.

The great organ flute is frequently used to give brilliancy to light combinations. Thus it may be used with the stopped diapason alone, or with the 16 bourdon alone, or with any of these and either or both of the open diapasons. Where the diapasons are scarcely strong enough to assert themselves in accompaniment, it is a very common practice to put the 4 flute into the diapason composition.

If any such use is made of the flute it is desirable that it should not be too strong; but its habitual use to give point to the diapasons is in every way to be deprecated. If the diapasons are not strong enough, let them be altered; but that...

The grooves of the soundboard are spaces left between wooden bars glued on to the table of the soundboard. There is usually one groove for every key. The grooves of the bass notes, which have to supply wind for large pipes, are broader than those of the treble. The bass bars are also thicker than those of the treble, that they may the better support the great weight which rests on the bass portion of the soundboard. The table forms the top of the grooves. The grooves are generally-closed below with leather, except the opening left in each, which is closed by the key-valve or pallet.

The sliders are connected with the draw-stops or stophandles, which are covered in with stout upper boards, on which the pipes stand. The stophandles are pulled out, and holes are then bored straight down through the upper boards, sliders, and table to admit the wind from the grooves to the pipes. When the sliders are shifted by pushing in the handles, the holes no longer correspond, and the pipes are silenced.

Pipes are divided first into flue-pipes and reed-pipes. Flue-pipes are blown by a wind mouthpiece characteristic of the organ, while in reed-pipes the wind acts on a metal tongue vibrating on a reed, and the motion of the tongue determines the speech of the pipe.

Pipes are made either of wood or of metal. Wood flue-pipes are generally of the form of a rectangular parallelepiped, metal fluepipes of a cylindrical shape. Reed-pipes are conical or pyramidal, and widen towards the top. Some flue-pipes are made with stopped ends; these as a rule sound a note about an octave lower than the corresponding open pipes of the same length. Such are the stopped diapason, bourdon, and stopped flute.

The general elementary theory of the resonance of a pipe is tolerably simple. The effective length of the pipe is determined by measuring from the upper lip to the open end in open pipes, and from the upper lip to the stopper and back again in stopped pipes. To this is added an allowance for the effect of each opening, since the condition of perfect freedom from constraint does not subsist at the opening itself. The corrected length is traversed twice (backwards and forwards) by sound, in the time of one vibration of the resultant note. This describes in a rough and general manner the way in which any disturbance gives rise to the note of the pipe; but the theory of the mouthpieces is a much more difficult matter, into which we cannot here enter.

In reed-pipes which are simply conical the resonance of the body is nearly the same as that of an open pipe of the same length. Where the form is irregular no simple rule can be given. But the resonance of the body of the pipe is generally the same as the note produced. The tongue of a reed-pipe alternately opens and closes the aperture of the reed. In this way it admits pulses of wind to the body of the pipe; these, if they recur at the proper intervals, maintain its vibration, which takes place when the note produced corresponds to the resonance of the pipe. The reed itself has its vibrating length determined by a wire which presses against it. The free end of this wire is touched with the tuning tool until a satisfactory note is produced.

The pitch of the different stops is commonly denoted by the conventional approximate length of the pipe sounded by C, the lowest key of the manual. Even in incomplete stops which have no bass, the length of the pipe which C would have if the stop were extended down serves to indicate the pitch.

The conventional length of the C-pipe for stops having the normal pitch of the keys is 8 feet; a pipe having twice this length sounds the octave below, a pipe having half that length the octave above, and so on. Thus stops which sound the octave below the normal pitch of the keys are spoken of as 16-foot stops. Even where the pipes are stopped so that the actual length is only 8 feet, they are spoken of as having “16-foot tone.” Similarly 32-foot stops sound two octaves below the normal pitch of the keys. But if these notes are produced by stopped pipes, whose actual length is only 16 feet, they are spoken of as having “32-foot tone.” Sixteen-foot and 32-foot stops are specially characteristic of the pedal, where the names also signify the length of the open pipe which would sound the note actually produced by the lowest C. In old organs, where the modern compass was not adopted, it was not unusual to find stops spoken of as of 12 feet or of 24 feet. In these cases the lowest note was frequently F. Old English organs, however, more often had G for their lowest note. The designation of the stops in these cases had become rather anomalous, and need not be entered into. Of stops higher than the normal pitch of the keys, the octave is denoted by 4 feet if made with open pipes, 4-foot tone if stopped; the twelfth is commonly spoken of as 2f, the fifteenth or double octave as 2 feet. Higher-sounding stops are occasionally used, but these generally form part of “mixtures,” and the foot-lengths of the separate ranks are not usually given.

The true or accurate lengths of the pipes vary within considerable limits. The base of the scales (dimensions) varies according to the standard of pitch, and the voicing and the complicated natural laws of pipes produce other deviations from simple relations, so that the conventional dimensions can only be regarded as a simple means of classifying the stops according to their pitch-relations. For this purpose they are essential; they are continually appealed to in discussion and description; and they are almost invariably marked on the stop-handles in all countries, so that a moderate knowledge of foreign nomenclatures, combined with the habit of seizing the meaning of the figures such as 16, 8, 4, on the stop-handles, will frequently suffice as a key to the complexities of a foreign organ.

Each of the manuals, or rows of keys, of an organ constitutes a separate organ, which is more or less complete in itself. The names of the different manuals or organs are great organ, swell organ, choir organ, and solo organ. The fifth manual, where it occurs, is the echo organ. The above is the usual order in point of development and frequency of occurrence, although the solo is sometimes preferred to the choir organ. The great organ is in a certain sense the principal department of the organ. It may be regarded as formed by a completely developed series of those fundamental stops which constitute the solid basis of the tone of the instrument. If an instrument be constructed with only a single manual this necessarily assumes, in general, the characteristics of a great organ. The great organ is called “grande orgue” in French, and first manual or “haupt-werk” in German.

It is proposed to describe the principal organ-stops under the heads of the manuals to which they belong. The enumeration will not be exhaustive, but will include all the usual types.

The great organ commences generally with stops of 16-foot length or tone in large instruments. In some cases a 32-foot sounding stop is introduced, but this cannot be said to be a proper characteristic of the great organ. The foundation tone is of 8 feet; the stops of higher pitch serve to add brilliancy; those of 16 feet, which sound the octave below the normal pitch, serve to add gravity and weight to the tone. Sixteen-foot stops are commonly spoken of as “doubles,” their conventional length being twice that of stops of normal pitch.

The 16-foot stops are the 16 double open diapason, and the 16 bourdon or double stopped diapason, to which, in very large instruments, there may be added a 16 double trumpet. The double open diapason on the great organ consists usually of metal pipes, having moderate “scale” or transverse dimensions. These are of the same general character as the pipes of the ordinary open diapason, though they are made somewhat less powerful. In the better instruments of the second class as to size this stop alone would probably be regarded as representing suitably and sufficiently the class of doubles on the great organ. It gives great body to the general tone, and appears decidedly preferable to the bourdon, which frequently takes its place. The 16 double dulciana may be regarded as a variation of the double open diapason. It is sometimes used where the full effect of a double open is not considered desirable. It possesses the light and not full tone of the dulciana. It does not appear to be peculiarly suitable for the purposes of a double.

The 16 bourdon or double stopped diapason, when used on the great organ, is made of rather small scale and light tone. It gives great body to a large great organ, and affords interesting combinations with other stops, such as the 4-foot flute. It is used either alone in smaller organs of the second class or in addition to a double open in larger instruments. The notes are produced from wooden pipes of rectangular section, stopped at the end, and having half the conventional length,

The 16 double trumpet is a trumpet (large reed stop) sounding the octave below the normal pitch. It is used generally in instruments of the largest size, but is somewhat more common in Germany. It is useful in giving a massive character to the tone of the full great organ, which is otherwise apt to become disagreeable on account of the great development of stops of a piercing character. If, however, the double trumpet is rough in tone, it is apt to communicate to the whole a corresponding impression.

The judicious balancing of such elements as the double trumpet and the piercing stops such as mixtures is one of the principal features of a good German great organ.

We now proceed to the 8-foot stops (the reeds come at the end according to ordinary usage). An ordinary great organ may contain 8 stopped diapason, 8 open diapason (one or more), 8 gamba, and 8 hohlflöte. The 8 stopped diapason on the great organ is usually of wood, of moderate scale, and some considerable fulness of tone. The actual lengths are about half the conventional lengths. These pipes are sometimes made of metal. Few stops admit of more variety and individuality in their quality of tone than the stopped diapason; but too frequently the great organ stopped diapason fails to attract attention on its merits, being regarded simply as an inconsiderable portion of the foundation tone.

If there is any one stop which in itself represents the organ as a whole it is the open diapason. The pipes of this stop are the typical metal pipes which have always been characteristic of the appearance of the organ. A single open diapason stop is capable of being used as an organ of sufficient power for many purposes, though of course without variety. The pipes of this stop are called “principal” in German, this appellation apparently corresponding to the fact that they are the true and original organ-pipes. The English appellation of “diapason” has been taken to mean that these are the normal pipes which run through the whole compass. This, however, does not appear to be the actual derivation of the term; originally it is technically applied to the organ-builder’s rule, which gives the dimensions of pipes; and it appears that the application to the stop followed on this meaning.

The scales, character, and voicing of the open diapason vary with fashion, and are different in different countries. We may distinguish three principal types. The old English diapasons of the days before the introduction of pedal organs into England were characterized by a rich sweet tone, and were not very powerful. They were generally voiced on a light wind, having a pressure equivalent to that of a column of water of from 2 to 2∣ inches. The scale was in some cases very large, as in Green’s two open diapasons in the old organ at St George’s, Windsor; in these the wind was light and the tone very soft. In other cases the scale was smaller and the voicing bolder, as in Father Smith’s original diapasons in St Paul’s Cathedral. But on the whole the old English diapasons presented a lovely quality of tone. English travellers of those days, accustomed to these diapasons, usually found foreign organs harsh, noisy, and uninteresting. And there are many still in England who, while recognizing the necessity of a firmer diapason tone in view of the introduction of the heavy pedal bass, and the corresponding strengthening of the upper departments of the organ tone, lament the disappearance of the old diapason tone. However, it is possible with care to obtain diapasons presenting the sweet characteristics of the old English tone, combined with sufficient fulness and power to form a sound general foundation. And there can be no doubt that this should be one of the chief points to be kept in view in organ design.

The German diapason was of an entirely different character from the English. The heavy bass of the pedals has been an essential characteristic of the German organ for at least two or three centuries, or, as it is said, for four. The development of the piercing stops of high pitch was equally general. Thus foundation work of comparatively great power was required to maintain the balance of tone; the ordinary German diapason was very loud, and we may almost say coarse, in its tone when compared with the old English diapason. The German stop was voiced as a rule on from 3 J to 4 inches of wind, not quite twice the pressure used in England.

The French diapason is a modern variety. It may be described as presenting rather the characteristics of a loud gamba than of a diapason. In other words, the tone tends towards a certain quality which may be described as “tinny” or metallic, or as approaching to that of a string instrument of rather coarse character. Some modern English builders appear to aim at the same model, and not without success.

The tone of a diapason must be strong enough to assert itself. It is the foundation of the whole organ tone. It is the voicer’s business to satisfy this condition in conjunction with the requirement that the tone shall be full and of agreeable quality.

The 8 spitzflöte may be regarded as a variety of open diapason. The pipes taper slightly towards the top, and the quality is slightly stringy. This stop was much used at one time in place of a second open diapason. But it appears better that, where two open diapasons are desirable, they should both be of full diapason quality, though possibly of different strengths and dimensions. The admixture of stringy qualities of tone with the diapasons is always to be deprecated.

The 8 gamba was originally an imitation of the viola da gamba, a sort of violoncello. When made of a light quality of tone it is a pleasing stop; but its use in the great organ instead of a second open diapason is greatly to be deprecated for the reasons just stated. It is frequently found that, where a gamba is provided on the great organ, it is necessary to remove it from the compositions (mechanical arrangements for pulling out the stop-handles in different combinations), as the tone does not blend.

The 8 hohlflöte is an open flute, usually of wood, and of small scale. If made to a moderate scale and fully voiced it possesses a full pleasant tone, which is a useful support to the foundation tone of the great organ. The 8 clarabella differs from the hohlflöte in being usually of rather large scale, and having the open pipes only in the treble. In old organs a separate bass was generally provided; now it is more usual to supply the stop with a stopped bass. The dulciana and keraulophon, though sometimes found on the great organ, are regarded as more appropriately placed elsewhere.

The 4-foot stops of the great organ comprise the 4 principal and the 4 flute. The 4 principal is the octave of the open diapason, generally of somewhat reduced scale and light but bright quality of tone. The use of the word “principal” in connexion with this stop is purely English, and is said to be connected with the use made of it as the standard of tuning for the whole organ. The Germans and French both designate this stop as “octave.”

Of the 4 flute there are several varieties,—open, stopped, wood, metal, and harmonic. The harmonic flute has open metal pipes of double the conventional length, which speak their octave. This is determined partly by the voicing, partly by making a small hole about the middle of the length, which determines the motion as that of the two separate lengths between which the hole lies. Harmonic flutes have a sweet but full and powerful tone. Other flutes are generally rather light, except the waldflöte, which is a powerful stop of a somewhat hooting quality.

The great organ flute is frequently used to give brilliancy to light combinations. Thus it may be used with the stopped diapason alone, or with the 16 bourdon alone, or with any of these and either or both of the open diapasons. Where the diapasons are scarcely strong enough to assert themselves in accompaniment, it is a very common practice to put the 4 flute into the diapason composition.

If any such use is made of the flute it is desirable that it should not be too strong; but its habitual use to give point to the diapasons is in every way to be deprecated. If the diapasons are not strong enough, let them be altered; but that...