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History of Technology in Islam (3) - Al-Shia The Scientific and Cultural Website of Shia belief History of Technology in Islam (3) 2021-06-24 512 Views Islam and Science , Technology In this part of the article “History of technology in Islam”, we shall be looking at some other landmark contributions of Islam in the field of technology. Contents Water Clocks Candle Clocks Miscellaneous Conclusions Water Clocks Al-Jazari’s clocks all employed automata to mark the passage of the hours.

These included birds that discharged pellets from their beaks onto cymbals, doors that opened to reveal the figures of humans, rotating Zodiac circles, the figures of musicians who struck drums or played the trumpets and so on. Generally speaking, the prime movers transmitted power to these automata by means of pulley systems and tripping mechanisms.

In the largest of the water clocks, which had a working face of about 11 feet high by 4.5 feet wide, the drive came from the steady descent of a heavy float in a circular reservoir. Clearly, some means of maintaining a constant outflow from the reservoir was needed and was indeed achieved in a most remarkable way. A pipe made of cast bronze led out from the bottom of the tap, and its end was bent down at right angles and formed into the seat of a conical valve.

Directly below this outlet sat a small cylindrical vessel in which there bobbed a float with the valve plug on its upper surface. When the tap opened, water ran into the float chamber, the float rose and caused a plug to enter the valve’s seat. Water was thus discharged from a pipe at the bottom of the float chamber, and the valve opened momentarily, whereupon water entered from the reservoir, the valve closed momentarily and so on.

An almost constant head was therefore maintained in the float chamber by feedback control, and the large float in the reservoir descended at a continuous speed. Al-Jazari said he got the idea for his invention from a simpler version, which he attributed to Archimedes. This clock did not record equal hours of 60 minutes each, but temporal hours, that is to say, the hours of daylight or darkness were divided by 12 to give hours that varied with the seasons.

This measurement required another piece of equipment: the pipe from the float chamber leading into a flow regulator, a device that allowed the orifice to be turned through a complete circle and thus to vary the static head below the surface of the water in the reservoir.