Born : 1136 CE, Cizre, Artuqid State
Died : 1206 CE
Badīʿ az-Zaman Abu l-ʿIzz ibn Ismāʿīl ibn ar-Razāz al-Jazarī (1136–1206,
Arabic: بديع الزمان أَبُ اَلْعِزِ إبْنُ إسْماعِيلِ
إبْنُ الرِّزاز الجزري ) was a Muslim
polymath: a scholar, inventor, mechanical engineer, artisan, artist and mathematician.
He is best known for writing The Book of Knowledge of Ingenious Mechanical
Devices (Arabic: كتاب في معرفة الحيل الهندسية, romanized: Kitab fi ma'rifat al-hiyal al-handasiya,
lit. 'Book in knowledge of engineering tricks') in 1206, where he described 100
mechanical devices, some 80 of which are trick vessels of various kinds, along
with instructions on how to construct them.
Life story
Diagram of a hydropowered perpetual flute from The Book of Knowledge of
Ingenious Mechanical Devices by Al-Jazari in 1206.
The only biographical information known about him is contained in his famed
Book of Knowledge of Ingenious Mechanical Devices. Like his father before him,
he served as chief engineer at the Artuklu Palace, the residence of the Mardin
branch of the Artuqids which ruled across eastern Anatolia as vassals of the
Zengid dynasty of Mosul and later of Ayyubid general Saladin.
Al-Jazari was part of a tradition of artisans and was thus more 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 Banū Mūsā brothers for his fountains,
al-Saghani for the design of a candle clock, and Hibatullah 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
The most significant aspect of al-Jazari's machines are the mechanisms,
components, ideas, methods, and design features which they employ.
Camshaft
A camshaft, a shaft to which cams are attached, was introduced in 1206 by
al-Jazari, who employed them in his automata, water clocks (such as the candle
clock) and water-raising machines. The cam and camshaft also appeared in
European mechanisms from the 14th century.
Crankshaft and crank-slider mechanism
The eccentrically mounted handle of the rotary quern-stone in fifth century
BCE 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
crankpins 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 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 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 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's hydropowered saqiya chain pump device.
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 the 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,
created automatic doors as part of one of his elaborate water clocks, and
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 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.
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!
Musical robot band
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.
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 in 1976
Al-Jazari also invented monumental water-powered astronomical clocks which
displayed moving models of the Sun, Moon, and stars.
Candle clocks
One of al-Jazari's candle clocks.
According to Donald 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 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, 14th century copy.
Castle clock
Further information: Clock tower.
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. Another innovative feature was the ability
to reprogram the length of day and night in order to account for their changes
throughout the year.
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. 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. Al-Jazari's castle clock is considered to be the earliest
programmable analog computer.
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.
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