The Works of Archimedes

in describing the same incident, says that a helix (spiral) was used. This term must be interpreted as referring to a machine similar to the kochlias (screw) described by Pappus, in which a cog-wheel with oblique teeth moves on a cylindrical helix turned by a handle. Pappus, however, describes it in connection with the baroulkos (weight-drawer) of Heron, and while he distinctly refers to Heron as his authority, he gives no hint that Archimedes invented either the baroulkos or that particular kochlias. On the other hand, the polyspastos (compound pulley) is mentioned by Galen and the trispastos (triple pulley) by Oribasius as one of the inventions of Archimedes, the trispastos being so called either from its having three wheels (Vitruvius) or three ropes (Oribasius). Nevertheless, it may well be that though the ship could easily be kept in motion, once started, by the trispastos or polyspastos, Archimedes was obliged to use an appliance similar to the kochlias to provide the initial impulse.

The name of yet another instrument appears in connection with the phrase about moving the earth. Tzetzes’ version is, "Give me a place to stand on, and I will move the whole earth with a charistion (lever/balance)"; but, as in another passage he uses the word trispastos, it may be assumed that the two words represented one and the same thing.

It will be convenient to mention in this place the other mechanical inventions of Archimedes. The best known is the