Ctésibios

Ctésibios of Alexandria (in Greek Κτησίϐιος / Ktêsíbios ), sometimes spelled Ktésibios , was an engineer born at third century BC with Alexandria. He is regarded as the founder of the school of the Greek mechanics of Alexandria whose tradition will continue with Philon de Byzance, Héron of Alexandria and until Vitruve.

One does not know large-thing on his life, nor the places and dates of his birth and his death. One knows just that he lived with Alexandria towards -270, bus of the documents speak about a singing Horn of plenty which he created for a statue of the woman of the Pharaon Ptolémée II.

Between the Piston, the hydraule, the keyboard, the Valve, the Hoist, the Clepsydre, the musical clock, the water cannon and many other invention, Ctésibios was an authentic genius. Its inventions had a major repercussion on the Western civilization.

It left a work now lost: the Comments . One knows of them bits thanks to Héron of Alexandria which took again of them fragments in its Pneumatique .

Biography

Wire of barber, it is interested very early in the Mécanique and operation of the machines with water: there are then seven Aqueduc S in Alexandria and of the hundreds of tanks and fountains.

Whereas it is only sixteen years old, it invents a kind of Monte-charge, to go up or go down from the tables, which functions thanks to Eau under Pression.

It also creates a system making it possible to direct the mirror of barber of its father in any direction, using a pneumatic system. The principle is still used in the return springs for the closing of the doors.

Improvement of the clepsydre

It is doubtless with the improvement of the Clepsydre that he knows a great fame. Created in Egypt, the clepsydre consisted of a tank full of water emptying itself by an opening in bottom, in a second container. This system was not very precise because the more the level of water in the first container drops, the more the thread of water which runs is weak: the water flow is thus irregular.

Ctésibios thus proposes to add a third container between two already what exists. This intermediate vase is maintained on constant level thanks to too full.

An alternative comprises a kind of float which more or less seals the opening of the first container as the second container fills. Thus, when water reaches a certain level in the second container, the opening in the first container is completely closed. And when the second container is emptied, the float releases this opening again, and the level goes up. Thus, the level of the water of the second container remains constant.

Consequently, the busy flow of water of 2nd to the 3rd container is constant. This clepsydre is thus much more reliable. This system is always used today, in and the carburettor flushings of car, for example.

Hydraule or machina hydraulica

Another admirable invention of Ctésibios is that of the hydraulic organ (hydraulos or hydraule), the first Orgue of the history. After having noted the elastic properties of the Air, Ctésibios seeks to control them by creating the Piston, which was not so simple at the time, because of the problems of escapes of air and more still, of manufacture of perfectly regular Cylindre S. To prove that its invention functions, it decides to make sound Aulos (kinds of Hautbois) thanks to its piston.

The problem of the regulation of the pressure of the air arises. Ctésibios proposes water like means of regulation.

The principle is simple and brilliant: a Bell in Bronze, pnigée, is immersed in a great volume of water. Two pistons feed a captive bubble of air under pnigée, via two pipes brought together at the top of pnigée. Valves or Soupape S prevent the return gate towards the pistons. Then, the air, under the pressure of water, leaves pnigée by one 3rd perforation at its top towards the pipes. A keyboard (which is thus also the invention of Ctésibios) makes it possible to open or close the access of the air these pipes: the first keyboard instrument was born, it is the hydraule ( hydr (O) - (" eau") + aulos (" flûte")). From which comes the current word from Hydraulique given to the Science of the water run-off.

These instruments had certainly reduced dimensions, but were extremely powerful (air pressure three times higher than that of the organ of today).

The hydraule is a success fantastic and fulgurating, which was never contradicted since. One started to very quickly organize contests of organ in all Greece. The hydraule was even used to cover the din of the spectators in the Roman circuses. One also found remainders of hydraules with Aquincum (today Budapest) in Hungary, with Dion in Greek Macedonia and with Pompéi (inter alia).

There is a complete description of the hydraule in Book X of the Of Structured of the great architect of Ier century Vitruve. Isaac Newton, 18 centuries later, will give him-also a description of the hydraule.

Other inventions

By associating the hydraule with the clepsydre, Ctésibios created the first musical clock. It then associated automats there, thus creating the first Jacquemart S.

It created gun S with water to send projectiles beyond the rampart S of the city. He proposed improvements with the water delivery system in Alexandria.

Sources

Hake Ronan, world History of sciences (1988), 2nd edition, Threshold (for the part on its life and the improvement of the clepsydre).

Articles hydraulus and horologium in '' Dictionnaire of Greek and Roman antiquities '', Daremberg and Saglio 1920.

Tittel, article hydraulus , in Realencyclopädie DER klassischen Altertumwissenschaft , Pauly and Wissowa.

CH. MacLean, The principle off the hydraulic organ . S.I.M. 1905.

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