the wear and tear of continuous motion, as in steam machines, is thus obviated. The power exerted is much more gradual than that of steam, performing the work more thoroughly, and with less liability to strain or otherwise damage the material operated upon, or the tool itself. * * * * * Although hydraulic machinery was successfully introduced by Sir William Armstrong so long ago as 1836, and has since been applied by him and others in almost every direction the application of hydraulic power to machines for constructive purposes is of comparatively modern date. Its early employment as the motive power for machine-tools was in the case of machines which were “stationary” or “fixed” in position when in use. Machines for riveting purposes in boiler shops and locomotive works were the first tools of any note to which hydraulic power transmitted from a distance was applied, but even this dates back only to about 1865. In that year Mr R. H. Tweddell, already referred to, designed hydraulic plant, consisting of pumps, an accumulator, and a riveting machine, which were first used by Messrs Thompson, Boyd & Co., Newcastle-on-Tyne, with satisfactory results. The work was done perfectly, and at about one-seventh of the cost of hand work, and the same power was utilized in actuating hydraulic presses for such purposes as setting or “joggling” angle or tee irons. Excellence and economy of work were thus secured; and in a comparatively short time above 100 machines were at work in various dockyards and large works.