warping-drums or capstans are fitted on a countershaft on the inner side of each frame, which drums can be driven independently of the travelling wheels for moving trucks into position below the crane as they are required for loading and unloading. Smaller cranes may pass with their loads below the gantry, and a number of these large cranes may be assembled so as each to work at the different hatchways of a large screw steamer, or two may be associated together for any exceptionally heavy lift. The value of elevation of the crane is not only in allowing the loaded cars to be brought on tracks beneath it, but in giving it capacity to work over the sides of large vessels, which when light may rise twenty feet above the level of the quay, and to load or discharge from trucks on two lines of rails on the land-side of the gantry, overhead of the trucks on the two lines which run below the gantry.[6] Blake's stone-breaker, though only represented by model in the United States section, where it belongs, is shown by two English firms; and though some Europeans profess to have improved upon its details, no efficient substitute has been found for it, but it remains the premium stone-crusher of the world, and has rendered services in the exploitation of gold quartz and silver ores, and in the crushing of stones for public works and for concretes, which can hardly be exaggerated. In testimony taken in the United States in 1872 it was put in evidence that five hundred and nine machines then in service effected a direct saving over hand-labor of five million five hundred thousand dollars per annum. Steam-pumps are here in force--direct by Tangye and others, and rotary by both of the Gwynnes, whose name has been so long and is so intimately associated with this class of machines. The emery-wheels of Thompson, Sterne & Co. of Glasgow have the same variety of form and application usual with us, but the firm claims that while it uses the true corundum emery of Naxos, the American article is only a refractory iron ore, which soon loses its sharpness and becomes inefficient. This is a question of efficiency or of veracity which we leave to the trade. The machine adapted as a tool-grinder has six emery-wheels for varying characters of work. Four are assorted for gauges of different radii, for moulding-irons, etc. One has a square face for plane-irons, chisels, etc. One is an emery hone to replace the water-of-Ayr stone. In examining the English locomotives exhibited two things were apparent: one half of them have adopted the outside cylinders and wrist-pins on the drivers, three out of four have comfortable cabs for the engineers. These are, as we view them, sensible changes. Outside-cylinder engines are also coming into extensive use in France. The machine tools shown by Sharp, Stewart & Co. of Manchester are remarkably well made, and their locomotive in the same space is an evidence of the efficiency of the tools.