The Columbia Encyclopedia, Sixth Edition. 2001-07.
Ctesibius
(tsb´s) (KEY) , fl. 2d cent. B.C., Alexandrian Greek inventor. He reputedly was the first to discover and apply the expansive power of air as a motive force. Among the inventions ascribed to him are a water clock (clepsydra), a hydraulic organ, and a force pump.