Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/334

the edges a little overlapping. It was then placed in a furnace, and being taken out when raised to a welding heat, a triblet, or cylinder of iron, was placed in it, and the whole was passed quickly through a pair of rollers. The effect of this was, that the welding was performed at a single heating, and the remainder of the elongation necessary for extending the skelps to the length of the musket barrel, was performed in a similar manner, but at a lower temperature. The workmen who had combined were, of course, no longer wanted, and instead of benefiting themselves by their combination, they were reduced permanently, by this improvement in the art, to a considerably lower rate of wages: for as the process of welding gun-barrels by hand required peculiar skill and considerable experience, they had hitherto been in the habit of earning much higher wages than other workmen of their class. On the other hand, the new method of welding was far less injurious to the texture of the iron, which was now exposed only once, instead of three or four times, to the welding heat, so that the public derived advantage from the superiority, as well as from the economy of the process. Another process has subsequently been invented, applicable to the manufacture of a lighter kind of iron tubes, which can thus be made at a price which renders their employment very general. They are now to be found in the shops of all our larger ironmongers, of various lengths and diameters, with screws cut at each end; and are in constant use for the conveyance of gas for lighting, or of water for warming, our houses.