GEARING IN THE ANCIENT-WORLD

Gears were invented by the Greek mechanics of Alexandria in the third century B. C., were considerably developed by the great Archimedes, and saw wide use in the Roman world. They found two main applications: in heavy-duty machines such as mills and irrigation wheels, where they transmitted considerable power, and in small-scale water-clocks, calendrical instruments and automata which could be of extraordinary sophistication, incorporating the differential and perhaps the hypoid gear. They became the ancestors of all modern gearing.