Al Jazari (1136–1206) was a Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, mathematician and astronomer from Al-Jazira, Mesopotamia, who lived during the Islamic Golden Age (Middle Ages). He is best known for writing the Book of Knowledge of Ingenious Mechanical Devices in 1206, where he described fifty mechanical devices along with instructions on how to construct them.
Little is known about al-Jazari, and most of that comes from the introduction to his Book of Knowledge of Ingenious Mechanical Devices. He was named after the area in which he was born, Al-Jazira—the traditional Arabic name for what was northern Mesopotamia and what is now south-Eastern Turkey , between the Tigris and the Euphrates. Like his father before him, he served as chief engineer at the Artuklu Palace, the residence of the Mardin branch of the Turkish Artuqid dynasty which ruled across eastern Anatolia as vassals of the Zangid rulers of Mosul and later Ayyubid general Saladin.
Al-Jazari was part of a tradition of craftsmen and was thus more of a practical engineer than an inventor 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.” 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.
Some of his devices were inspired by earlier devices, such as one of his monumental water clocks, which was based on that of a Pseudo-Archimedes. He also cites the influence of the Banu Musa brothers for his fountains, al-Asturlabi for the design of a candle clock, and Hibat Allah ibn al-Husayn (d. 1139) for musical automata. Al-Jazari goes on to describe the improvements he made to the work of his predecessors, and describes a number of devices, techniques and components that are original innovations which do not appear in the works by his precessors.
Mechanisms and methods:
While many of al-Jazari’s inventions may now appear to be trivial, the
most significant aspect of al-Jazari’s machines are the mechanisms,
components, ideas, methods, and design features which they employ.
Camshaft:
The camshaft, a shaft to which cams are attached, was first introduced
in 1206 by al-Jazari, who employed them in his automata,[7] water
clocks (such as the candle clock) and water-raising machines. The cam
and camshaft later appeared in European mechanisms from the 14th
century.
Crankshaft and crank-slider mechanism:
The eccentrically mounted handle of the rotary handmill in 5th century
BC Spain that spread across the Roman Empire constitutes a crank. The
earliest evidence of a crank and connecting rod mechanism dates to the
3rd century AD Hierapolis sawmill in the Roman Empire. The crank also
appears in the mid-9th century in several of the hydraulic devices
described by the Banū Mūsā brothers in their Book of Ingenious Devices.
In 1206, al-Jazari invented an early crankshaft, which he incorporated with a crank-connecting rod mechanism in his twin-cylinder pump. Like the modern crankshaft, Al-Jazari’s mechanism consisted of a wheel setting several crank pins into motion, with the wheel’s motion being circular and the pins moving back-and-forth in a straight line. The crankshaft described by al-Jazari transforms continuous rotary motion into a linear reciprocating motion. and is central to modern machinery such as the steam engine, internal combustion engine and automatic controls.
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. His water pump also employed the first known crank-slider mechanism.
Design and construction methods:
English techonology historian Donald Routledge Hill writes:
We see for the first time in al-Jazari’s work several concepts
important for both design and construction: the lamination of timber to
minimize warping, the static balancing of wheels, the use of wooden
templates (a kind of pattern), the use of paper models to establish
designs, the calibration of orifices, the grinding of the seats and
plugs of valves together with emery powder to obtain a watertight fit,
and the casting of metals in closed mold boxes with sand.
Escapement mechanism in a rotating wheel:
Al-Jazari invented a method for controlling the speed of rotation of a wheel using an escapement mechanism.
Mechanical controls:
According to Donald Routledge Hill, al-Jazari described several early
mechanical controls, including “a large metal door, a combination lock
and a lock with four bolts.”
Segmental gear:
A segmental gear is “a piece for receiving or communicating
reciprocating motion from or to a cogwheel, consisting of a sector of a
circular gear, or ring, having cogs on the periphery, or face.”
Professor Lynn Townsend White, Jr. wrote:
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.
Water-raising machines:
Al-Jazari invented five machines for raising water, as well as
watermills and water wheels with cams on their axle used to operate
automata, in the 12th and 13th centuries, and described them in 1206.
It was in these water-raising machines that he introduced his most
important ideas and components.
Saqiya chain pumps:
The first known use of a crankshaft in a chain pump was in one of
al-Jazari’s saqiya machines. The concept of minimizing intermittent
working is also first implied in one of al-Jazari’s saqiya chain pumps,
which was for the purpose of maximising the efficiency of the saqiya
chain pump. Al-Jazari also constructed a water-raising saqiya chain
pump which was run by hydropower rather than manual labour, though the
Chinese were also using hydropower for chain pumps prior to him. Saqiya
machines like the ones he described have been supplying water in
Damascus since the 13th century up until modern times, and were in
everyday use throughout the medieval Islamic world.
Double-action suction pump with valves and reciprocating piston motion:
Citing the Byzantine siphon used for discharging Greek fire as an
inspiration, al-Jazari went on to describe the first suction pipes,
suction pump, double-action pump, and made early uses of valves and a
crankshaft-connecting rod mechanism, when he invented 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:
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. This was more advanced than the suction pumps that appeared in 15th-century Europe, which lacked delivery pipes. It was not, however, any more efficient than a noria commonly used by the Muslim world at the time.
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.
Automata:
al-Jazari built automated moving peacocks driven by hydropower. He
also invented the earliest known automatic gates, which were driven by
hydropower. He also created automatic doors as part of one of his
elaborate water clocks, and designed and constructed a number of other
automata, including automatic machines, home appliances, and musical
automata powered by water. He also invented water wheels with cams on
their axle used to operate automata. According to Encyclopædia
Britannica, the Italian Renaissance inventor Leonardo da Vinci may have
been influenced by the classic automata of al-Jazari.
Mark E. Rosheim summarizes the advances in robotics made by Arab 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.
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.
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.
Hand-washing automaton with flush mechanism:
al-Jazari invented a hand washing automaton incorporating a flush
mechanism now used in modern flush toilets. It features a female
humanoid automaton standing by a basin filled with water. When the user
pulls the lever, the water drains and the female automaton refills the
basin.
Peacock fountain with automated servants:
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:
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!
Al-Jazari’s 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.
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. According to
Charles B. Fowler, the automata were a “robot band” which performed
“more than fifty facial and body actions during each musical
selection.”
Clocks:
al-Jazari constructed a variety of water clocks and candle clocks.
These included a portable water-powered scribe clock, which was a meter
high and half a meter wide, reconstructed successfully at the Science
Museum (London) in 1976 Al-Jazari also invented monumental
water-powered astronomical clocks which displayed moving models of the
Sun, Moon, and stars.
Candle clocks:
According to Donald Routledge Hill, al-Jazari described the most
sophisticated candle clocks known to date. Hill described one of
al-Jazari’s candle clocks as follows:
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.
Elephant clock:
The elephant clock was 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.
Automatic castle clock of al-Jazari, 12th century.
Programmable castle clock:
al-Jazari’s largest astronomical clock was the “castle clock”, which
is considered to be one of the first programmable analog computer. It
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.
Another innovative feature was the variable ability to re-program the
length of day and night everyday in order to account for the changing
lengths of day and night throughout the year. Yet another innovative
feature of the device was five robotic musicians who automatically play
music when moved by levers operated by a hidden camshaft attached to a
water wheel. Other components of the castle clock included a main
reservoir with a float, a float chamber and flow regulator, plate and
valve trough, two pulleys, crescent disc displaying the zodiac, and two
falcon automata dropping balls into vases.
Weight-driven water clocks:
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.
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.