Science - Elephant water clock
Origin and time: Istanbul, around 600/1200
Al-Jami, Hs. Istanbul, Topkapi, Saray, Ahmet III 3472, p.90
Elephant, figures and tower made of wood; tower and serpents made of brass; water container inside elephant made of copper
Size: 230 cm
Inv. No. B 1.06
This is the life-size replica of a water clock as designed and described by Al-Jazari in his book Al-Jami Bain Al-Ilm Wal-Amal in 600/1200. It strikes at half-hour intervals 48 times a day, thus indicating 24 equal hours. (For demonstration purposes, the intervals of this replica were cut down to three minutes.) A “scribe” sitting on the back of the elephant signalises the intervals by minimally moving his reed pen along a scale line every 30 minutes. Moreover, a figure sitting in the tower indicates half and full hours by lifting the left or right arm. The timing mechanism is caused by a semispherical bowl floating in a water-filled bucket inside the elephant. At the bottom, the bowl has a hole just big enough to let through the right amount of water within 30 minutes to make the bowl lose buoyancy and sink. In the process of sinking, the bowl pulls a string attached to a mechanism in the tower. This releases a ball that causes several figures to move when the ball drops. A bird turns, the figure in the tower alternatively lifts the right or left arm, two serpents move downwards and pull the bowl back to its former position. The scribe moves and the figure sitting on the head of the elephant beats a drum with the left hand and strikes the elephant with a whip in the right hand.
Unlike sundials, another old means of measuring the time, water clocks benefit from the fact that they are independent of sunlight. They are believed to have been invented by the Egyptians. In the Temple of Amon in Karnak, archaeologists found parts of a water clock dating back to the 14th century BC. During the golden age of Alexandria, the water clock was extremely popular. Archimedes, a visitor of the city, shared his knowledge and experience on hydraulics with his scholar, the barber Ctesibius. In the second century BC, Ctesibius made a clock with a clock-face and hands, which is why Marcus Vitruvius incorrectly called him the inventor of the water clock.
Fuat Sezgin: Wissenschaft und Technik im Islam, Institut für Geschichte der Arabsich-Islamischen Wissenschaften an der Johann Wolfgang Goethe-Universität, Frankfurt am Main. 2003