On Architecture

4. A block should then be attached by a stout cord to the top of the machine, and from that point a rope should be carried to a pile, and to a block tied to the pile. Let the rope be put in round the sheave of this block, and brought back to the block that is fastened at the top of the machine. Round its sheave the rope should be passed, and then should go down from the top, and back to the windlass, which is at the bottom of the machine, and there be fastened. The windlass is now to be turned by means of the handspikes, and it will raise the machine of itself without danger. Thus, a machine of the larger kind will be set in position, with its ropes in their places about it, and its stays attached to the piles. Its blocks and traction ropes are arranged as described above.

5. But if the loads of material for the work are still more colossal in size and weight, we shall not entrust them to a windlass, but set in an axle-tree, held by sockets as the windlass was, and carrying on its centre a large drum, which some term a wheel, but the Greeks call it a)mfi/esis or periqh/kion.

6. And the blocks in such machines are not arranged in the same, but in a different manner; for the rows of sheaves in them are doubled, both at the bottom and at the top. The traction rope is passed through a hole in the lower block, in such a way that the two ends of the rope are of equal length when it is stretched out, and both portions are held there at the lower block by a cord which is passed round them and lashed so that they cannot come out either to the right or the left. Then the ends of the rope are brought up into the block at the top from the outside, and passed down over its lower sheaves, and so return to the bottom, and are passed from the inside to the sheaves in the lowest block, and

7. Passing over these from the outside, they are then carried to the right and left of the drum on the axle-tree, and are tied there so as to stay fast. Then another rope is wound round the drum and carried to a capstan, and when that is turned, it turns the drum and the axle-tree, the ropes get taut as they wind round regularly, and thus they raise the loads smoothly and with no danger. But if a larger drum is placed either in the middle or at one side, without any capstan, men can tread in it and accomplish the work more expeditiously.

8. There is also another kind of machine, ingenious enough and easy to use with speed, but only experts can work with it. It consists of a single timber, which is set up and held in place by stays on four sides. Two cheeks are nailed on below the stays, a block is fastened by ropes above the cheeks, and a straight piece of wood about two feet long, six digits wide, and four digits thick, is put under the block. The blocks used have each three rows of sheaves side by side. Hence three traction ropes are fastened at the top of the machine. Then they are brought to the block at the bottom, and passed from the inside round the sheaves that are nearest the top of it. Then they are brought back to the upper block, and passed inwards from outside round the sheaves nearest the bottom.

9. On coming down to the block at the bottom, they are carried round its second row of sheaves from the inside to the outside, and brought back to the second row at the top, passing round it and returning to the bottom; then from the bottom they are carried to the summit, where they pass round the highest row of sheaves, and then return to the bottom of the machine. At the foot of the machine a third block is attached. The Greeks call it e)pa/gwn but our people “artemon.” This block fastened at the foot of the machine has three sheaves in it, round which the ropes are passed and then delivered to men to pull. Thus, three rows of men, pulling without a capstan, can quickly raise the load to the top.

10. This kind of machine is called a polyspast, because of the many revolving sheaves to which its dexterity and despatch are due. There is also this advantage in the erection of only a single timber, that by previously inclining it to the right or left as much as one wishes, the load can be set down at one side. All these kinds of machinery described above are, in their principles, suited not only to the purposes mentioned, but also to the loading and unloading of ships, some kinds being set upright, and others placed horizontally on revolving platforms. On the same principle, ships can be hauled ashore by means of arrangements of ropes and blocks used on the ground, without setting up timbers.