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TWO:"You see, I have found something out," he said. "I rather hoped--indeed, I have still hopes--that the culprit----" More info

TWO:"Do they contain anything likely to help us, Prout?""But how did you know that I had it?" More info

TWO:To make this plainer, the laws of forces, the proportion of parts, strength of material, and so on, are subjects of general knowledge that may be acquired from books, and understood without the aid of an acquaintance with the technical conditions of either the mode of constructing or the manner of operating machines; but how to construct proper patterns for castings, or how the parts of machinery should be moulded, forged, or fitted, is special knowledge, and must have reference to particular cases. The proportions of pulleys, bearings, screws, or other regular details of machinery, may be learned from general rules and principles, but the hand skill that enters into the manufacture of these articles cannot be learned except by observation and experience. The general design, or the disposition of metal in machine-framing, can be to a great extent founded upon rules and constants that have general application; but, as in the case of wheels, the plans of moulding such machine frames are not governed by constant rules or performed in a uniform manner. Patterns of different kinds may be employed; moulds may be made in various ways, and at a greater and less expense; the metal can be mixed to produce a hard or a soft casting, a strong or a weak one; the conditions under which the metal is poured may govern the soundness or shrinkage,��things that are determined by special instead of general conditions.In operating by elastic blows, the steam piston is cushioned at both the up and down stroke, and the action of a steam-hammer corresponds to that of a helve trip-hammer, the steam filling the office of a vibrating spring; in this case a hammer gives a quick rebounding blow, the momentum being only in part [111] spent upon the work, and partly arrested by cushioning on the steam in the bottom of the cylinder under the piston. More info