As we must anyway shape the metal into useful implements and other products, it is fortunate that the quality of the metal is benefited by the process. [Illustration: No. 69a. PHOTOMICROGRAPH OF COLD-DRAWN STEEL WIRE SHOWING DISTORTION OF THE CRYSTALS FROM COLD WORKING Hot Working does not produce distortion but makes the grain finer. Annealing relieves this distortion to a great extent. (_Magnification 70 Diameters._) ] Forging [Illustration: [Man]] Undoubtedly the earliest shaping of ferrous (iron) metals was by hammering the small balls of metal into bars, spears or swords. Presumably it was done with stone hammers which later had to give way to hammers made of iron. These had sufficient hardness to serve the purpose well. For hundreds of centuries the shaping of iron, steel and the other metals into tools and weapons must have been done by such forging methods. It is not difficult for us to picture the early smiths at their work, laboriously and yet very skillfully hammering into spear-heads and sword-blades the lumps of iron or Wootz Steel which they had made in their crude furnaces. [Illustration: THE OLD OLIVER FOOT-POWER HAMMER ] [Illustration: AN OLD FORGE HAMMER ] In much the same way, though on a considerably larger scale and with heavier and better hammers and tools, was the same work done up to the time of the invention of Cort’s rolling process—about 1783. Various styles of hammers were used, some with a spring pole attached to raise them for the next stroke which was delivered by foot power, others known as “helve” or “shingling” hammers gave periodical blows as teeth on a revolving wheel lifted and allowed the hammer heads to fall. The heavier ones often gave as many as seventy-five and the lighter ones which were used for “tilting” (forging) shear steel into bars or implements as high as three hundred blows per minute. [Illustration: THE SQUEEZER WAS SOMETIMES USED IN PLACE OF THE HAMMER ] [Illustration: THE OLD TILT HAMMER ] Though Cort’s rolls very materially aided in the shaping of balls of iron from the puddling furnace into bars, the hammering or forging method remained the one by which finished iron and steel articles were made. About 1835 it happened that a very large propeller shaft for a new ship was desired. Being so large, no one was found who could forge it until the matter was put before an English iron-worker named James Nasmyth, who had a reputation for ingenuity. Nasmyth roughly sketched out an immense hammer which he proposed to operate by steam. There was no opportunity to build it, however, for the propeller shaft never was ordered. But the idea of the steam hammer got to certain French engineers, who constructed one which Nasmyth came upon during a visit to a French iron works. Nasmyth realized the importance of his invention, which, luckily, the Frenchmen had not attempted to patent. A patent was granted to Nasmyth. [Illustration: