=335. Development of machine tools for working iron.=—Iron was little used, partly because it was hard to get and partly because it was hard to work. There were in England about 1800 only three good machine shops, where small steam-engines were built. The equipment of even the best machine shop would seem now wretchedly inadequate, and Stephenson was greatly hampered, in building his first locomotive, by the lack of good machine tools, for working metals. William Fairbairn said in his presidential address before the British Association at Manchester, “When I first entered this city [about 1813] the whole of the machinery was executed by hand. There were neither planing, slotting, nor shaping machines; and, with the exception of very imperfect lathes, and a few drills, the preparatory operations of construction were effected entirely by the hands of the workmen.” About 1825 to 1830, however, with the growth in demand for iron-working apparatus, there began a rapid development of this branch of manufacture, one step in advance leading rapidly to another. We may trace the process in the description that Nasmyth gives us of his first machine shop, a shed measuring 24 by 16 feet. “I removed thither my father’s foot-lathe, to which I had previously added an excellent slide-rest of my own making. I also added a ‘slow motion,’ which enabled me to turn cast-iron and cast-steel portions of my great Mandsley lathe. I soon had the latter complete and in action. Its first child was a planing machine capable of executing surfaces in the most perfect style; it was 3 feet long by 1 foot 8 inches wide. Armed with these two most important and generally useful tools, and by some special additions, such as boring machines and drilling machines, I soon had a progeny of legitimate descendants crowded about my little workshop, so that I often did not know which way to turn.” Nasmyth himself made one specially important contribution to iron-working machinery, by the invention of the steam hammer in 1839; the old “bit by bit” system of welding became henceforth unnecessary.