« Vitr. 10.2 | Vitr. 10.2 | Vitr. 10.3 | About This Work »
8There is another species of machine, ingenious in respect of its contrivance, and of ready application in practice; but it should not be used except by experienced persons. A pole or log of timber is raised, and kept in its situation by means of four guy ropes in opposite directions. Under the place where the guy ropes at top are made fast to the pole, two cheeks are fixed, above which the block is tied with ropes. Under the block, a piece of timber about two feet long, six inches wide, and four inches thick, is placed. The blocks have three ranks of pulleys latitudinally, so that it is necessary to conduct three leading ropes from the upper part of the machine; these are brought down to the lower block, and are passed through its upper pulleys from the side next the pole. They then are carried to the upper block, passing from the outer sides of the lower pulleys to the inner sides of the lower pulleys of the upper block.
« Vitr. 10.2 | Vitr. 10.2 | Vitr. 10.3 | About This Work »