‹‹‹ Vitr. 9.8.4 | Table of Contents | Vitr. 9.8.6 ›››
5the water flowing through the hole equably, raises an inverted bowl, called by the workmen phellos, or the tympanum, with which are connected a rule and revolving drum wheels with perfectly equal teeth, which teeth, acting on one another, produce revolutions and measured motion. There are other rules and other wheels, toothed in a similar manner, which acted upon by the same force in their revolutions, produce different species of motion, by which figures are made to move, cones are turned round, stones or oviform bodies are ejected, trumpets sounded, and similar conceits effected.
5A regular flow of water through the orifice raises an inverted bowl, called by mechanicians the “cork” or “drum.” To this are attached a rack and a revolving drum, both fitted with teeth at regular intervals. These teeth, acting upon one another, induce a measured revolution and movement. Other racks and other drums, similarly toothed and subject to the same motion, give rise by their revolution to various kinds of motions, by which figures are moved, cones revolve, pebbles or eggs fall, trumpets sound, and other incidental effects take place.