2We will begin by describing those engines which are chiefly used in the erection of sacred buildings, and other public works. They are made as follows: three pieces of timber are prepared suitable to the greatness of the weights to be lifted, connected at the top by a pin, but spreading extensively at their feet. These are raised by means of ropes made fast to the top, and when raised, are thereby kept steady. To the top is then made fast a block, by some called rechamus. In this block are two pulleys, turning on axles; over the upper pulley passes the leading rope, which, let fall and drawn through under the lower pulley of the bottom block is returned thence over the lower pulley of the upper block: the rope again descends to the lower block, and its end is made fast to the eye of it. We refer the other end of the rope to the description of the lower part of the machine.
2First we shall treat of those machines which are of necessity made ready when temples and public buildings are to be constructed. Two timbers are provided, strong enough for the weight of the load. They are fastened together at the upper end by a bolt, then spread apart at the bottom, and so set up, being kept upright by ropes attached at the upper ends and fixed at intervals all round. At the top is fastened a block, which some call a “rechamus.” In the block two sheaves are enclosed, turning on axles. The traction rope is carried over the sheave at the top, then let fall and passed round a sheave in a block below. Then it is brought back to a sheave at the bottom of the upper block, and so it goes down to the lower block, where it is fastened through a hole in that block. The other end of the rope is brought back and down between the legs of the machine.