“The first planing machine enabled us to produce the second still better, and that a better still, and then slide rests of the most perfect kind came streaming forth from them, and they again assisted in making better still, so that in a very short time a most important branch of engineering business, namely, tool-making, arose, which had its existence not merely owing to the pre-existing demand for such tools, but in fact raised a demand of its own creating. One has only to go into any of these vast establishments which have sprung up in the last thirty years to find that nine-tenths of all the fine mechanisms in use and in process of production are through the agency, more or less direct, of the _slide rest and planing machine_.” Springing out of these inventions, as from a fruitful soil, came the metal-boring machines, one class for turning the outside of cylinders to make them true, and another class for boring and drilling holes through solid metal plates. The principle of the lathe was applied to those machines in which the shaft carrying the cutting or boring tool was held either in a vertical or in a horizontal position. Now flowed forth, as from some Vulcan’s titanic workshop, machines for making bolts, nuts, rivets, screws, chains, staples, car wheels, shafts, etc., and other machines for applying them to the objects with which they were to be used. The progress of screw-making had been such that in 1840, by the machines then in use for cutting, slotting, shaving, threading, and heading, twenty men and boys were enabled to manufacture 20,000 screws in a day. Thirty-five years later two girls tending two machines were enabled to manufacture 240,000 screws a day. Since then the process has proceeded at even a greater rate. So great is the consumption of screws that it would be utterly impossible to supply the demand by the processes in vogue sixty years ago. In England’s first great International Fair, in 1851, a new world of metallurgical products, implements, processes, and metal-working tools, were among the grand results of the half century’s inventions which were exhibited to the assembled nations. The leading exhibitor in the line of self-acting lathes, planing, slotting, drilling and boring machines was J. Whitworth & Co., of Manchester, England. Here were for the first time revealed in a compact form those machines which shaped metal as wood alone had been previously shaped. But another quarter of a century brought still grander results, which were displayed at the Centennial Exhibition at Philadelphia, in 1876.