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which the ropes are passed, for the men to work them.Thus, three sets of men, working without the interven-tion of a capstan, quickly raise the weight to its requiredheight. This species of machine is called Polyspaston,because the facility and dispatch in working it, is obtain-ed by means of many pulleys. One convenience in usinga single pole is, that the situation of the weight in rela-tion to the pole, whether before it or to the right or leftof it, is of no consequence. All the machines above de-scribed, are not only adapted to the purposes mentioned,but are also useful in loading and unloading ships, someupright, others horizontal, with a rotatory motion. Onthe ground, however, without the aid of the poles, shipsare drawn on shore by the mere application of blocks andropes.