Ctesibius of Alexandria
Ctesibius of Alexandria was an influential Hellenistic inventor and craftsman known for his pioneering work in the field of pneumatics. Born in Alexandria, Egypt, during the reign of Ptolemy Soter, he came from a modest background, with his father being a barber who likely influenced his early mechanical experiments. Ctesibius is most famously credited with inventing the water organ and the water pump, as well as perfecting the first accurate water clock, which utilized innovative designs for water flow regulation. His work contributed significantly to the cultural and intellectual environment of Alexandria, particularly during the reign of Ptolemy Philadelphus, who supported artistic and scientific endeavors. Though much of his original work has been lost, subsequent technical writers such as Vitruvius and Hero of Alexandria documented his contributions. Ctesibius's inventions not only demonstrated his mechanical genius but also laid the groundwork for future advancements in technology and engineering. His legacy continues to be recognized, highlighting the importance of practical ingenuity in the ancient world.
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Subject Terms
Ctesibius of Alexandria
Alexandrian inventor
- Born: c. 290 b.c.e.
- Birthplace: Alexandria, Egypt
- Died: Probably after 250 b.c.e.
- Place of death: Alexandria, Egypt
One of the great mechanical geniuses and inventors of antiquity, Ctesibius was the father of pneumatics, the first to employ compressed air to run his devices. He is credited with a number of inventions, including a water pump, a water organ, a precise water clock, and bronze spring and pneumatic catapults.
Early Life
Biographical details about Ctesibius (tee-SIHB-ee-uhs) are scarce. He was from Alexandria in Egypt and would have grown up during the reign of Ptolemy Soter, who, following the death of Alexander the Great, founded the Ptolemaic Dynasty in Egypt in 322. Ctesibius’s father was a barber, a trade he apparently taught his son. Ctesibius is said to have married a woman named Thais.
Vitruvius, the first century b.c.e.architect and military engineer who utilized Ctesibius’s lost treatise on pneumatics, describes him as an industrious youth, endowed with great natural ability, who occupied much of his time amusing himself with the ingenious devices he routinely fashioned. The most famous anecdote about Ctesibius has him devising a counterweight system to raise and lower a mirror in his father’s barbershop. As the counterweight moved rapidly through a narrow channel, it compressed trapped air, which escaped with a loud noise. The sounds and tones created supposedly gave Ctesibius the idea for his water organ, for which he used pipes of different lengths to vary pitch and water to pressurize the air.
The same barbershop experiment apparently also inspired Ctesibius’s water pump, which consisted of two vertical cylinders, each with a plunger worked reciprocally by a rocker arm. Water was drawn into a cylinder chamber through a valve connected to a water source when its plunger was raised and then was forced out in the direction desired through another valve when its plunger was lowered. Continuous pumping on the rocker arm handle guaranteed a steady flow of water.
Life’s Work
Much of Ctesibius’s adult life was spent during the reign of Ptolemy Philadelphus, for whom he fashioned a singing cornucopia for a statue of Arsinoe, the king’s deified wife, about 270. Because of his mechanical skills, it can be safely assumed that he was often employed by Ptolemy to produce other machines, both serious and amusing (for example, singing birds to grace water clocks and call out the hour).
Alexandria at that time had become the cultural center of the Hellenistic world. The Ptolemaic court was never more brilliant than under Ptolemy Philadelphus, who, while expanding Egyptian power overseas, was responsible for the Great Library and Museum and one of the Seven Wonders of the Ancient World, the lighthouse on the island of Pharos at the entrance to Alexandria’s harbor. This was almost certainly the period of Ctesibius’s greatest achievements, which, because his own work is lost, are known primarily through three later technical writers—Vitruvius (De architectura, after 27 b.c.e.; On Architecture, 1914), Philon of Byzantium (Mechanikē syntaxis, third century b.c.e.), and Hero of Alexandria (Pneumatica, c. 62 c.e.; The Pneumatics of Hero of Alexandria, 1851).
In addition to inventing the water organ and pump, Ctesibius perfected the first accurate water clock. Previous water clocks did not keep precise time because the flow of water to the clock could not be correctly regulated. Ctesibius first fashioned orifices of gold or other substances that would not be worn by the action of water and did not collect dirt. Having guaranteed an uninterrupted water flow into the first chamber of the clock, Ctesibius then devised a way to keep the water level in that chamber constant. An automatic valve, worked by a float, shut off the supply when the water in the chamber rose too high and opened it again as soon as enough water had drained into the clock’s second chamber. The flow of water from the first chamber to the second, consequently, was always the same, and the passage of a certain amount of water represented the passage of so much time. On the simplest of water clocks, elapsed time could be determined by noting the markings on the side of the second chamber. More elaborate water clocks had complex and imaginative ways of denoting the time.
Significance
While perhaps not as familiar today as some of his famous scientific and technological contemporaries, Ctesibius of Alexandria was one of the greatest Hellenistic inventors and the founder of pneumatics. Primarily a craftsman, Ctesibius had little interest in theoretical issues, but he was a mechanical genius of the first rank. He was influenced by and contributed to the cultural and intellectual atmosphere characterizing the reigns of Ptolemy Soter and especially Ptolemy Philadelphus, by whom he was employed. Over his lifetime, he produced several important devices that would have lasting value, among them a water pump, a water organ, the first accurate water clocks, and improvements to artillery.
Bibliography
Cohen, M. R., and I. E. Drabkin. A Source Book in Greek Science. Cambridge, Mass.: Harvard University Press, 1966. A compilation of passages from ancient writers about science and technology. Includes references to Ctesibius.
Drachmann, A. G. The Mechanical Technology of Greek and Roman Antiquity. Madison: University of Wisconsin Press, 1963. The standard study of the literary sources for Greek and Roman technology, particularly Hero of Alexandria’s Mechanica (c. 62 c.e.).
Landels, J. G. Engineering in the Ancient World. Rev. ed. Berkeley: University of California Press, 2000. An excellent survey of ancient engineering. Includes discussion of Ctesibius’s contributions, some illustrated.
Lloyd, G. E. R. Greek Science After Aristotle. New York: W. W. Norton, 1973. A good brief survey of ancient science, beginning with the Hellenistic period. Discusses Ctesibius’s work, with some illustrations.
Sarton, George. A History of Science. 2 vols. New York: W. W. Norton, 1970. A standard survey of the history of Hellenistic science and culture. Ctesibius’s achievements are considered.
Vitruvius Pollio. Vitruvius: Ten Books on Architecture. Translated by Ingrid D. Rowland. New York: Cambridge University Press, 1999. In books 9 and 10, Vitruvius provides more details about Ctesibius and his work than any other ancient writer.