The Greek inventor and mathematician of Ctesibius (Ktesibios, Tesibius, Κτησίβιος) of Alexandria, supposedly originally a barber, and also possibly the first head of the Museum of Alexandria, made several contributions to hydraulic engineering. He invented the hydraulis, a water organ that is considered the precursor of the modern pipe organ. This instrument was not an automaton since it required a human player.
Ctesibius described one of the first force pumps for producing a jet of water, or for lifting water from wells, examples of which have been found at various Roman sites, such as at Calleva Atrebatum (Silchester) in Britain. The principle of the siphon has also been attributed to him. In his De architectura Vitruvius described the water organ and credited the force pump to Ctesbius.
"The hydraulis was the world's first keyboard instrument and was, in fact, the predecessor of the modern church organ. Unlike the instrument of the Renaissance period, which is the main subject of the article on the pipe organ, the ancient hydraulis was played by hand, not automatically by the water-flow; the keys were balanced and could be played with a light touch, as is clear from the reference in a Latin poem by Claudian (late 4th century), who uses this very phrase (magna levi detrudens murmura tactu . . . intonet, “let him thunder forth as he presses out mighty roarings with a light touch”) (Paneg. Manlio Theodoro, 320–22)" (Wikipedia article on Hydraulis [Water organ], accessed 12-25-2011).