The labor saved by this hammer is immense. One man sits perched up on the frame to direct it, and another stands below to guide the iron on the anvil. The great long bar, white with heat, is pulled out of the furnace, laid on the massive piece of iron under the frame, and, with a dull, heavy sound, down conies the hammer, swiftly or slowly, according to the wishes of the director. From the forge and the foundry the "rough-hewn" iron-work passes to be planed, and its surface to be made "true." The wheel of an engine or a carriage, for example, after being forged by the black-smith, requires to be most carefully cut round the rim, so that the space between the flange--that is, the projecting inner part of the wheel, and the outer part--may be perfectly conical, in order that the least amount of surface may be exposed to the rail, and consequently the least amount of friction produced. Again, when a cylinder comes from the foundry, the interior must be cut and polished to a perfect circle, otherwise it would be useless. In short, there is no part of a locomotive that does not require to be prepared with the most perfect accuracy to fit some other part; and if this accuracy is not gained, the engine will either not work at all, or work very imperfectly. It must be remembered that it is hard metal, like iron and brass, that has thus to be wrought on, not comparatively soft material, like wood and stone. But the machinery employed at Crewe seems capable of cutting any thing, even though it were a rock of adamant. You pass into a shed full of little machines, standing separate from each other, with all manner of curious wheels and belts, driven by steam, of course, and each with a man stationed by its side, gazing attentively at the little machine, as if he were absorbed in thought; and, indeed, were it not for an occasional quick movement of his hands, and a rapid change of position, you might almost suppose that he was sleeping on his legs. But go close up, and you notice that the machine is slowly moving backward and forward, and still more slowly at the same time in a lateral direction. Some curious piece of mechanism is placed on it, and the movements of the machine cause a sharp steel-cutter to pass over the iron surface, which cuts it as easily and truly as a joiner planes a piece of fir. The side motion brings all the surface gradually under the instrument, but the machine, clever and powerful though it is, requires to be constantly watched and regulated, and hence the fixed attention of the man in charge. At a large machine, you will see those long, curious rods called "eccentrics" undergoing this operation; at another, a cylinder is being planed; and at a third, the rims of wheels are being cut. The filings thus made are preserved, and will be seen in large heaps in a yard, ready to be melted down, and "used up" again. In some cases both iron and brass filings are produced, which, of course, are mixed with each