Ismail al-Jazari

Badīʿ az-Zaman Abu l-ʿIzz ibn Ismāʿīl ibn ar-Razāz al-Jazarī (1136–1206,

Al-Jazari was born in the area of

Al-Jazari was part of a tradition of artisans and was thus more a practical engineer than an inventor^[16] who appears to have been "more interested in the craftsmanship necessary to construct the devices than in the technology which lay behind them" and his machines were usually "assembled by trial and error rather than by theoretical calculation".^[17] His Book of Knowledge of Ingenious Mechanical Devices appears to have been quite popular as it appears in a large number of manuscript copies, and as he explains repeatedly, he only describes devices he has built himself. According to Mayr, the book's style resembles that of a modern "do-it-yourself" book.^[18]

Some of his devices were inspired by earlier devices, such as one of his monumental water clocks, which was based on that of a

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  Court scene. Amid, modern-day Diyarbakır, Turkey, 1206 (Ms. Ahmet III 3472).^[20]
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  Mechanical Turkic servant. Amid, modern-day Diyarbakır, Turkey, 1206 (Ms. Ahmet III 3472).^[20]
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  Female servant. Amid, modern-day Diyarbakır, Turkey, 1206 (Ms. Ahmet III 3472).^[20]
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  Mechanical Turkic servant. Amid, modern-day Diyarbakır, Turkey, 1206 (Ms. Ahmet III 3472).^[20]

Mechanisms and methods

The most significant aspect of al-Jazari's machines are the

A camshaft, a shaft to which cams are attached, was described in 1206 by al-Jazari, who employed them in his automata,^[22] water clocks (such as the candle clock)^[23] and water-raising machines.^[22]

Crankshaft and crank-slider mechanism

The eccentrically mounted handle of the rotary

He used the crankshaft with a connecting rod in two of his water-raising machines: the crank-driven saqiya chain pump and the double-action reciprocating piston suction pump.^[28][30] His water pump also employed the first known crank-slider mechanism.^[8]

Design and construction methods

English technology historian Donald Hill writes:

We see for the first time in al-Jazari's work several concepts important for both design and construction: the

casting of metals in closed mold boxes with sand.^[9]

Al-Jazari invented a method for controlling the speed of rotation of a wheel using an escapement mechanism.^[31]

Mechanical controls

According to Donald Hill, al-Jazari described several early mechanical controls, including "a large metal door, a combination lock and a lock with four bolts".^[9]

Segmental gear

A segmental gear is "a piece for receiving or communicating

Segmental gears first clearly appear in al-Jazari, in the West they emerge in Giovanni de Dondi's astronomical clock finished in 1364, and only with the great Sienese engineer Francesco di Giorgio (1501) did they enter the general vocabulary of European machine design.^[33]

Water-raising machines

Al-Jazari invented five machines for raising water,

Double-action suction pump with valves and reciprocating piston motion

Citing the Byzantine siphon used for discharging Greek fire as an inspiration,^[38] al-Jazari went on to describe his version of suction pipes, suction pump, double-action pump, and made early uses of valves and a crankshaft-connecting rod mechanism, when he developed a twin-cylinder reciprocating piston suction pump. This pump is driven by a water wheel, which drives, through a system of gears, an oscillating slot-rod to which the rods of two pistons are attached. The pistons work in horizontally opposed cylinders, each provided with valve-operated suction and delivery pipes. The delivery pipes are joined above the centre of the machine to form a single outlet into the irrigation system. This water-raising machine had a direct significance for the development of modern engineering. This pump is remarkable for three reasons:^{[9][39][40][41]}

• The first known use of a true suction pipe (which sucks fluids into a partial vacuum) in a pump.
• The first application of the double-acting principle.
• The conversion of rotary to reciprocating motion via the crank-connecting rod mechanism.

Al-Jazari's suction piston pump could lift 13.6 metres of water,^{[citation needed]} with the help of delivery pipes. It was not, however, any more efficient than the noria commonly used by the Muslim world at the time.^[42]

Water supply system

al-Jazari developed the earliest water supply system to be driven by gears and hydropower, which was built in 13th century Damascus to supply water to its mosques and Bimaristan hospitals. The system had water from a lake turn a scoop-wheel and a system of gears which transported jars of water up to a water channel that led to mosques and hospitals in the city.^[43]

Automata

Al-Jazari built automated moving peacocks driven by hydropower.^[44] He also created automatic doors as part of one of his elaborate water clocks,^[9] and invented water wheels with cams on their axle used to operate automata.^[34] According to Encyclopædia Britannica, the Italian Renaissance inventor Leonardo da Vinci may have been influenced by the classic automata of al-Jazari.^[45]

Mark E. Rosheim summarizes the advances in robotics made by Muslim engineers, especially al-Jazari, as follows:

Unlike the Greek designs, these Arab examples reveal an interest, not only in dramatic illusion, but in manipulating the environment for human comfort. Thus, the greatest contribution the Arabs made, besides preserving, disseminating and building on the work of the Greeks, was the concept of practical application. This was the key element that was missing in Greek robotic science.^[46]

The Arabs, on the other hand, displayed an interest in creating human-like machines for practical purposes but lacked, like other preindustrial societies, any real impetus to pursue their robotic science.^[47]

Drink-serving waitress

One of al-Jazari's humanoid automata was a waitress that could serve water, tea or drinks. The drink was stored in a tank with a reservoir from where the drink drips into a bucket and, after seven minutes, into a cup, after which the waitress appears out of an automatic door serving the drink.^[48]

Hand-washing automaton with flush mechanism

Al-Jazari invented a hand washing automaton incorporating a flush mechanism now used in modern flush toilets. This device is another example of humanoid automata. It consisted of a human figure, made from jointed copper, holding a pitcher resembling a peacock in its right hand. The pitcher is made from brass and holds within it a chamber, divided into two parts by a metal plate. This mechanism aided the pouring of the water from the spout so that it was smooth and would not splutter. The reservoir in which the water is held is situated within the right-hand side of the human figure. An axle is fitted into the right elbow of the human figure so as to allow the liquid to pour from the reservoir through the spout of the pitcher. The left arm of the figure had a fixed weight which would raise and lower the arm which would hold a towel, comb and mirror.

This automaton was designed to aid the king whilst he performed his ritual ablutions. A servant of the king would carry the figure and place it next to a basin that could hold liquid. The servant then turned a knob on the back of the figure which opened a valve resulting in the pouring of water from the right hand of the figure into the basin. When the reservoir is nearly empty and most of the water has been poured a mechanism is prompted and the left hand of the figure, holding the towel, comb and mirror, is extended out in the direction of the king so that he can dry himself and tend to his beard.^[49]

Peacock fountain with automated servants

Water and its usages holds particular importance in Islam; both as being an integral part of the pre-prayer washing processes wudu and ghusl, and a key feature in Islamic gardens – four fountains featuring in the Paradise Garden; the Islamic final resting place referenced in the Quran. Additionally, with Mesopotamia being a naturally drought-ridden place, machines relating to water held a significant function; in both a divine and practical sense.

An entire section of The Book of Knowledge of Ingenious Mechanical Devices was devoted to fountain mechanisms, titled: ‘On the construction in pools of fountains which change their shape, and of machines for the perpetual flute’.^[50]

Al-Jazari's "peacock fountain" was a more sophisticated hand washing device featuring humanoid automata as servants which offer soap and towels. Mark E. Rosheim describes it as follows:^[46]

Pulling a plug on the peacock's tail releases water out of the beak; as the dirty water from the basin fills the hollow base a float rises and actuates a linkage which makes a servant figure appear from behind a door under the peacock and offer soap. When more water is used, a second float at a higher level trips and causes the appearance of a second servant figure – with a towel!

The basin of the "peacock fountain" formed the basin for performing wudu, and it would have been operated by a servant, who would have pulled the plug and positioned the peacock's beak; allowing the mechanism to release the water into the basin in front of the user.^[51]

However, whilst water moving objects such as the peacock fountain had ritualistic usage, there is suggestion that water-moving hydraulics were put to profane use. Ayhan Aytes suggests that:^[52]

Many of the devices also had additional functions that contradicted divine omnipotence. The most profane purpose of several of his hydraulic and pnuematic automata was to get guests at parties drunk as quickly as possible.

Musical robot band

Al-Jazari's work described fountains and musical automata, in which the flow of water alternated from one large tank to another at hourly or half-hourly intervals. This operation was achieved through his innovative use of hydraulic switching.^[9]

Al-Jazari created a musical automaton, which was a boat with four automatic musicians that floated on a lake to entertain guests at royal drinking parties. Professor Noel Sharkey has argued that it is quite likely that it was an early programmable automata and has produced a possible reconstruction of the mechanism; it has a programmable drum machine with pegs (cams) that bump into little levers that operated the percussion. The drummer could be made to play different rhythms and different drum patterns if the pegs were moved around.^[53]

The water-clock of the drummers

The water-clock of the drummers, which differs from the Musical robot band in that it lacks a flute-playing

According to Donald Hill, al-Jazari constructed the most sophisticated candle clocks known to date. Hill described one of al-Jazari's candle clocks as follows:^[9]

The candle, whose rate of burning was known, bore against the underside of the cap, and its wick passed through the hole. Wax collected in the indentation and could be removed periodically so that it did not interfere with steady burning. The bottom of the candle rested in a shallow dish that had a ring on its side connected through pulleys to a counterweight. As the candle burned away, the weight pushed it upward at a constant speed. The automata were operated from the dish at the bottom of the candle. No other candle clocks of this sophistication are known.

Al-Jazari's candle clock also included a dial to display the time and, for the first time, employed a bayonet fitting, a fastening mechanism still used in modern times.^[58]

Elephant clock

The elephant clock described by al-Jazari in 1206 is notable for several innovations. It was the first clock in which an automaton reacted after certain intervals of time (in this case, a humanoid robot striking the cymbal and a mechanical robotic bird chirping) and the first water clock to accurately record the passage of the temporal hours to match the uneven length of days throughout the year.^[59]

Castle clock

Al-Jazari's largest astronomical clock was the "castle clock", which was a complex device that was about 11 feet (3.4 m) high, and had multiple functions besides timekeeping. It included a display of the zodiac and the solar and lunar orbits, and an innovative feature of the device was a pointer in the shape of the crescent moon which travelled across the top of a gateway, moved by a hidden cart, and caused automatic doors to open, each revealing a mannequin, every hour.^[9][60]

Another feature of the device was five automata musicians who automatically play music when moved by levers operated by a hidden camshaft attached to a water wheel.^[23]

Al-Jazari invented water clocks that were driven by both water and weights. These included geared clocks and a portable water-powered scribe clock, which was a meter high and half a meter wide. The scribe with his pen was synonymous to the hour hand of a modern clock.^[34][57] Al-Jazari's famous water-powered scribe clock was reconstructed successfully at the Science Museum, London in 1976.

Miniature paintings

Alongside his accomplishments as an inventor and engineer, al-Jazari was also an accomplished artist. In The Book of Knowledge of Ingenious Mechanical Devices, he gave instructions of his inventions and illustrated them using miniature paintings, a medieval style of Islamic art.

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  One of al-Jazari's candle clocks.
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  The musical robot band designed by al-Jazari.
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  A table device automaton designed by al-Jazari.
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  The hand-washing automaton with a flush mechanism designed by al-Jazari.
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  Al-Jazari's hydropowered saqiya chain pump device.
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  An illustration of a device invented by al-Jazari.
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  A sketch of a device designed by al-Jazari. From the manuscript of Kitabal Al-Hial in Aga Khan Museum, Toronto.

See also

• Hero of Alexandria
• History of the internal combustion engine
• List of inventions in the medieval Islamic world
• Islamic Golden Age
• Science in the medieval Islamic world
• Lists of Muslim scientists and scholars
• Taqi ad-Din Muhammad ibn Ma'ruf

Notes