In 1842 Nasmyth visited France, and was cordially received at Creuzot and shown about the works. “On entering,” he writes, “one of the things that particularly struck me was the excellence of a large wrought-iron marine engine single crank, forged with a remarkable degree of exactness in its general form. I observed also that the large eye of the crank had been punched and drifted with extraordinary smoothness and truth. I inquired of M. Bourdon ‘how that crank had been forged?’ His immediate reply was, ‘_It was forged by your steam hammer!_’... He told me ... that he had taken careful notes and sketches, and that among the first things he did after his return to Creuzot was to put in hand the necessary work for the erection of a steam hammer.... M. Bourdon conducted me to the forge department of the works, that I might, as he said, ‘_see my own child_’; and there it was, in truth--a thumping child of my brain.”[100] Fortunately it was still time to save his patent rights. He moved rapidly and in June, 1842, two months after his visit to Creuzot, a patent was obtained.[101]. The steam hammer soon found its way into all the large shops of the world and greatly increased Nasmyth’s already comfortable fortune. Nasmyth transferred his United States patent to S. V. Merrick of Philadelphia, who introduced the hammer into the American iron works. [100] _Ibid._, pp. 246-247. The self-acting valve motion for the steam hammer was invented by Mr. Wilson, when Nasmyth was absent on business. Wilson was manager at Patricroft and later became a partner. It was much used for a time but with the advent of balanced piston-valves the hand-operated gear supplanted it. Nasmyth’s invention of the hammer was denied by M. Schneider in 1871. For fuller discussion of the history of this hammer see _London Engineer_, May 16, 1890, and a pamphlet by T. S. Rowlandson, entitled “History of the Steam Hammer.” Manchester, 1866. [101] No. 9382, June 9, 1842. Besides work on the hammer and machine tools, Nasmyth made a number of inventions of interest. While still with Maudslay he invented the flexible shaft made of a coiled spring, and speaks with amusement at his finding the same idea in a dental engine many years later credited as an American invention. He invented the ball-and-socket joint for shafting hangers and also the single wedge gate valve. His steam piledriver, an adaptation of the steam hammer, was the invention in which he seems to have taken the most satisfaction. He was working out a method of puddling iron with a blast of steam when he was eclipsed by Bessemer’s brilliant invention, in 1855, of the air blast. Nasmyth was a member of the Small Arms Committee which remodeled the Small Arms Factory at Enfield. His connection with this will be taken up in the consideration of the rise of interchangeable manufacture.