Hanl-hammers and sledge-hammers being rigidly limited as to weight by the trifling power which one man—or at most two men—can bring to bear upon them, it long ago became obviously desirable to obtain the force of impact from some more powerful source than human muscles, so that the weight of hammer heads might be largely increased and their blows made proportionately more effective. The first step taken in this direction seems to have been the introduction of the “Hercules,” a ponderous mass of. iron attached to a vertical guide rod, which was lifted originally by a gang of men with ropes, but afterwards by steam power, and allowed to fall by its own weight. This was. a fairly efficient tool for forging large anchors and for similar purposes, the strength of the blow and the point at which it was delivered being easily regulated. But as the demand for wrought iron increased, the necessity for more rapid as well as more powerful hammers to aid in its manu facture increased also. The lift or helve hammer (fig. 2) and the tilt hammer (fig. 3) thus came into use, and under these forms hammers may be said to have ranked for the first time as true machine tools. Each of these consists of a heavy head attached to a beam mounted on gudgeons, which is lifted at regular intervals by suitable cams or pins carried by a revolving shaft driven by steam or other power, their chief points of difference being the relative position of the gudgeons and the portion of the beam at which the power is applied, as shown in the diagrams. Heavy blows are thus obtained with the one, and lighter but much more rapid blows with the other, both, however, invariable in their intensity, the lift being always to one fixed height.

In the steam hammer (fig. 4), which was first patented by Nasmyth in the year 1842, this objection is completely obviated. By the simple device of attaching the hammer head to the lower end of the rod of a piston working in an inverted steam cylinder, he produced a machine capable of being made to deliver its blows with a force to which no limit has yet been found, and yet so perfectly under control as to be able to crack a hazel nut without injuring the kernel. To the introduction of this invaluable tool is due more than to any other single cause the power which we now possess of producing the forgings in iron and steel which are demanded by the arts of modern times; and in one or other of its many forms it is now to be met with in every workshop in which heavy work is carried on. Many modifications of the Nasmyth steam hammer have been introduced. In one of these steam pressure has been applied above the piston to intensify the blow, it being only used in the original form for lifting the “tup” and piston and for regulating their descent. In another the piston and piston-rod have been attached to the framing, and the cylinder made movable, its weight being thu3 added to that of the hammer.

Duplex hammers differ materially from the ordinary steam hammer, inasmuch as no anvil is necessary,—two hammer heads of equal weight (and for some purposes they weigh only a few pounds, for others as much as 30 tons) being made to deliver horizontal blows of equal force simultaneously on opposite sides of the forging, which thus receive perfectly equal treatment. The importance of this may be gathered from the fact that every increase in the weight of the vertical steam hammer necessitates a very much larger increase in the weight and solidity of the anvil which is necessary to afford the requisite inertia for resisting the blow. For instance, the anvil of a 40-ton hammer now in use at Woolwich Arsenal weighs upwards of 160 tons, and has nearly 500 tons of iron in its foundation, whereas the anvil of an 80-ton hammer of which a full-sized model was amongst the most striking objects at the Paris Exhibition of 1878, is of no less than 720 tons weight.

The recent growth of steam hammers to the enormous size just mentioned is due chiefly to the large dimensions, independently of the mere weight, of the forgings which have now to be made for heavy ordnance and for other purposes. As long as the thickness of a forging is moderate, the reaction of the anvil acting upon, its under side has an effect not greatly inferior to that of the hammer on the upper side. But with every increase in thickness some of this reaction is lost and the effect of the blow is more and more confined to the outer portions of the mass, which thus receive more than their share of treatment at the expense of the central portions. On this account the difficulty of obtaining thick forgings thoroughly sound throughout their substance is very great, and it seems as if we had now reached the limit beyond which the hammer cannot be advantageously applied for their production.. It has been found indeed in the case of large shafts that dispensing altogether with the central portion, thus making them tubular instead of solid, is accompanied by an increase in their strength, owing to the possibility of thus forging the metal uniformly throughout. But a much more widely applicable remedy, and one which will doubtless come into general use for heavy work, is the substitution of hydraulic or other pressure for the force of impact, a system which has lately been employed by Sir Joseph Whitworth with wonderfully good results. The reason of the superiority of its effect seems to be mainly this, that a certain amount of time is essential for completing the “flow” of the metal which it is the object of forging to induce. Under continuous pressure this flow can take place uniformly throughout the mass, whereas the instantaneous blow of the hammer, though it acts violently on the surface particles, and to a decreasing extent on the adjacent ones, is entirely expended before the action has had time to reach those at the centre, so that unequal density and consequent weakness is the result. For massive forgings therefore the old saying can be no longer accepted that “there is.no machine like a hammer.” (c. p. b. s.)

It was natural that a scholar who traversed so large a field and wrote so rapidly should lay himself open to the criticism of specialists, and no man was more severely handled by his critics than Von Hammer, to whom Diez, for example (in Unfug und Betrug, 1815), devotes nearly 600 pages of heavy abuse. Von Hammer was undoubtedly inaccurate and superficial at times; he attempted more than he could possibly achieve with thoroughness, and was in the habit of giving his own whimsical view of matters about which he knew next to nothing; and he used to offend his critics as much by his Oriental florid style and want of method as by the occasional inaccuracy of his facts and the inconsequence of his deductions. But in spite of his faults he did more for Oriental studies than most of his critics put together.

When he was seventy-six years of age he planned a second edition of his Encyclopaedia of Oriental Learning , and designed a “preliminary” series of twelve volumes which should clear the ground by expounding the history of Arabic literature, aud for the last seven years of his life he regularly put forth his annual volume. Jules Mohl, going to see him, found the old man hard at work, helped by no colleague, and disdaining the aid of an amanuensis. His early travels in the Levant, and then bis busy life at Vienna, where he held the post of court-interpreter, saved him from the crushing influence of solitary study; and to the last he maintained his singular buoyancy of mind. “C’était un homme généreux, franc jusqu’à l’imprudence, hardi, bouillonnant d’esprit, aimable jusqu’à la coquetterie, doué d’une faculté de travail rare, ambitieux dans les grandes et les petites choses, et d’une vivacité inconcevable—vivacité qui fut la source de sa bonne et do sa mauvaise fortune.” So Mohl pictured him in his address to the Société Asiatique in 1857, when he recorded the death of Von Hammer on November 23, 1856, at the age of eighty-two, a hard worker to the last, like his younger but greater English contemporary Lane, with whom he came into collision in a friendly way on the subject of the origin of The Thousand and One Hights.

Von Hammer’s principal works are his Geschichte des osmanischen Reiches, 10 vols., 1827 (2d ed., 1834-6), translated into French (1835 and 1840); Geschichte der osmanischen Dichtkunst, 4 vols., 1836; Literatur-Geschichte der Araber (unfinished), 7 vols., 1850-6; Les Origines Russes, 1827; Geschichte der Goldenen Horde, 1840; Geschichte der Ilchane, 1842; Geschichte der Chane der Krim, 1856; Geschichte der Assassincn, 1818; Constantinopolis und der Bosporos, 1822; Enzyklopädische Uebersicht der Wissenschaften des Orients, 1804. Texts and translations of— Eth-ΤhaΛlabi, Arab, and Germ., 1829; Ibn Wahshiyah, History of the Mongols, Arab, and Engl., 1806; El-Wassâf, Pers, and Germ., 1856; Esch-Schebistani’s Rosenflor des Geheimnisses, Pers, and Germ., 1838; Ez-Zam-akhsheri, Goldene Halzbändcr, Arab, and Germ., 1835; El-GhazzΛli, Hujjet-el-Islàm, Arab, and Germ., 1838; El-Hamawi, Das arab. Hohe Lied der Liebe, Arab, and Germ., 1854. Translations of— El-Mutancbbi , s Poems; Er-Rcsmi's A ccount of his Em bassy, 1809; Contes inédits des 1001 Nuits, 1828. Besides these and smaller works, Von Hammer contributed numerous essays and criticisms to the Fundgrτιbcn des Orients, which he edited; to the Journal Asiatique; and to many other learned journals; above all to the Transactions of the Akademie der Wissenschaften of Vienna, of which he was mainly the founder; and he translated

Evliya Effendi’s Travels in Europe, for the English Oriental Translation Fund. For a fuller list of his works, which amount in all to nearly 100 volumes, see Comptes Rendus of the Acad, des Inscr. et des Belles Lettres, 1857.