Ctesibius in Wikipedia

Ctesibius or Ktesibios or Tesibius (Greek Κτησίβιος) (fl. 285–222 BC) was a Greek[1] inventor and mathematician in Alexandria, Ptolemaic Egypt. He wrote the first treatises on the science of compressed air and its uses in pumps (and even a cannon). This, in combination with his work on the elasticity of air On pneumatics, earned him the title of "father of pneumatics." None of his written work has survived, including his Memorabilia, a compilation of his research that was cited by Athenaeus. Inventions Ctesibius was probably the first head of the Museum of Alexandria. Very little is known of his life but his inventions were well known. It is said (possibly by Diogenes Laertius) that his first career was as a barber. During his time as a barber, he invented a clever counterweight-adjustable mirror. His other inventions include the hydraulis, a water organ that is considered the precursor of the modern pipe organ, and an improved water clock called a clepsydra. The clepsydra kept more accurate time than any clock invented until the Dutch physicist Christiaan Huygens detailed the use of a pendulum to regulate a clock in the 17th century. He described one of the first force pumps for producing a jet of water, or for lifting water from wells, and examples have been found at various Roman sites, such as at Silchester in Britain. The principle of the siphon has also been attributed to him. According to Diogenes Laertius, Ctesibius was miserably poor. Laertius details this by recounting the following concerning the philosopher Arcesilaus: "when he had gone to visit Ctesibius who was ill, seeing him in great distress from want, he secretly slipped his purse under his pillow; and when Ctesibius found it, 'This,' said he, 'is the amusement of Arcesilaus.'" [1]