- Warren Anderson
- , revised by Thomas J. Mathiesen
(fl Alexandria, 3rd century bce). Greek inventor. According to earlier scholarship, he was active during the reign of Ptolemy Euergetes I (246–221 bce). A review of the evidence by Perrot, however, supports the conclusion that he was active about 270 bce, the period of Ptolemy Philadelphus. He enjoyed wide fame in antiquity for his mechanical devices operated by the pressure of water or air. Often these were elaborate toys created to amuse the court: one such was a water-clock, with sounding trumpets among its ingenious fittings, made for Ptolemy's queen Arsinoë.
The most famous and significant of Ctesibius's inventions was the Hydraulis, or water-organ. While some references fail to establish him precisely as its discoverer, his claim is strengthened by the weight of the total evidence and the lack of any satisfactory alternative theory. Farmer argued that the case for Ctesibius is supported by the existence of an Alexandrian treatise, surviving only in Arabic translation; this describes and illustrates a hydraulic musical device of a type much earlier than that described by Vitruvius or by Hero of Alexandria. His attempt, however, to identify the author, a certain Muristus (whose name exists in several variant forms), with Ctesibius is highly conjectural and involves difficulties....