Muslim scientists

Al-Jazari بديع الزمان الجزري

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Badi’al-Zaman Abū al-‘Izz Ismā’īl ibn al-Razāz al-Jazarī (1136–1206) was aMuslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, and mathematician from Jazirat ibn Umar (current Cizre), who lived during the Islamic Golden Age (Middle Ages). He is best known for writing the al-Jāmiʿ bain al-ʿilm wa al-ʿamal al-nāfiʿ fī ṣināʿat al-ḥiyal (The Book of Knowledge of Ingenious Mechanical Devices) in 1206, where he described fifty mechanical devices along with instructions on how to construct them.

Biography

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 (the city of Jazirat ibn Umar). 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. He was born in the Kurdish city of Tor, now located in the district of Cizre in south-Eastern Turkey.

Diagram of a hydropowered water-raising machine

al-Jazari was part of a tradition of craftsmen and was thus more of a practical engineer than an inventorwho 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.

The Elephant Clock was one of the most famous inventions of Al-Jazari.

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,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-Jazaritransforms 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 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.

al-Jazari’s hydropowered saqiya chain pump device.

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,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, 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!

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 1976Al-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.

One of al-Jazari’s candle clocks.

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.

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.Another innovative feature was the ability to re-program the length of day and night in order to account for their changes throughout the year. Another feature of the device was five automaton 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.

Automatic castle clock of al-Jazari, 12th century.

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.

Ibn an-Nafis ابن النفيس

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Ala-al-din abu Al-Hassan Ali ibn Abi-Hazm al-Qarshi al-Dimashqi, known as Ibn al-Nafis, was an Arab physician who is mostly famous for being the first to describe the pulmonary circulation of the blood.

He was born in 1213 in Damascus. He attended the Medical College Hospital (Bimaristan Al-Noori) in Damascus. Apart from medicine, Ibn al-Nafis learned jurisprudence, literature and theology. He became an expert on the Shafi’i school of jurisprudence and an expert physician.

In 1236, Al-Nafis moved to Egypt. He worked at the Al-Nassri Hospital, and subsequently at the Al-Mansouri Hospital, where he became chief of physicians and the Sultan’s personal physician. When he died in 1288, he donated his house, library and clinic to the Mansuriya Hospital.

Writings

The most voluminous of his books is Al-Shamil fi al-Tibb, which was planned to be an encyclopedia comprising 300 volumes, but was not completed as a result of his death. The manuscript is available in Damascus.

His book on ophthalmology is largely an original contribution. His most famous book is The Summary of Law (Mujaz al-Qanun). Another famous book, embodying his original contribution, was on the effects of diet on health, entitled Kitab al-Mukhtar fi al-Aghdhiya. His Al-Risalah al-Kamiliyyah fil Siera al-Nabawiyyah, translated in the West under the title Theologus Autodidactus, has been argued to be both the first theological novel and the first science fiction novel.

He also wrote a number of commentaries on the topics of law and medicine. His commentaries include one on Hippocrates’ book, and several volumes on Avicenna’s The Canon of Medicine. Additionally, he wrote a commentary on Hunayn Ibn Ishaq’s book.

The opening page of one of Ibn al-Nafis’s medical works.

This is probably a copy made in India during the 17th or 18th century.

Discovery of Blood Circulation by Ibnu Nafis

Ala-al-Din Abu al-Hasan Ali Ibn Abi al-Hazm al-Qarshi al-Dimashqi (known as Ibn Al-Nafis) was born in 1213 A.D. in Damascus. He was educated at the Medical College Hospital (Bimaristan Al-Noori) founded by Noor al-Din Al-Zanki. Apart from medicine, Ibn al-Nafis learned jurisprudence, literature and theology. He thus became a renowned expert on the Shafi’i School of Jurisprudence as well as a reputed physician. In 1236

Ibn Nafis moved to Egypt and worked in Al-Nassri Hospital then in Al-Mansouri Hospital where he became chief of physicians and the Sultan’s personal physician. When he died in 1288 A.D. he donated his house, library and clinic to the Mansuriya Hospital .

The most voluminous of his books is Al-Shamil fi al-Tibb, which was designed to be an encyclopedia comprising 300 volumes, but was not completed as a result of his death. The manuscript is available in Damascus. His book on ophthalmology is largely an original contribution and is also extant. His book that became most famous, however, was Mujaz al-Qanun (The Summary of Law) and a number of commentaries that were written on this same topic. His commentaries include one on Hippocrates’ book, and several volumes on Ibn Sina’s Qanun, which are still extant. Likewise he wrote a commentary on Hunayn Ibn Ishaq’s book. Another famous book embodying his original contribution was on the effects of diet on health entitled Kitab al-Mukhtar fi al-Aghdhiya.

His major original contribution of great significance was his discovery of the pulmonary circulation, which was re-discovered by modern science after a lapse of three centuries. He was the first to correctly describe the constitution of the lungs and gave a description of the bronchi and the interaction between the human body’s vessels for air and blood. He also elaborated on the function of the coronary arteries as suppliers of blood to the cardiac musculature.

Ibn al-Haytham الحسن بن الحسن بن الهيثم

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Abu Ali al-Hasan ibn al-Hasan ibn al-Haytham (965 in Basra – c. 1040 in Cairo) was a prominent scientist and polymath from the ‘Golden Age’ of Muslim civilization. He is commonly referred to as Ibn al-Haytham, and sometimes as al-Basri, after his birthplace in the city of Basra. He is also known by his Latinized name of Alhzen or Alhacen.

Ibn al-Haytham made significant contributions to the principles of optics, as well as to physics, astronomy, mathematics, ophthalmology, philosophy, visual perception, and to the scientific method. He was also nicknamed Ptolemaeus Secundus (“Ptolemy the Second”) or simply “The Physicist” in medieval Europe. Ibn al-Haytham wrote insightful commentaries on works by Aristotle, Ptolemy, and the Greek mathematician Euclid.

Born circa 965, in Basra, Iraq, he lived mainly in Cairo, Egypt, dying there at age 76. Over-confident about practical application of his mathematical knowledge, he assumed that he could regulate the floods of the Nile.

After being ordered by al-Hakim bi-Amr Allah, the sixth ruler of the Fatimid caliphate, to carry out this operation, he quickly perceived the difficulty of what he was attempting to do, and retired from engineering. Fearing for his life, he feigned madness and was placed under house arrest, during and after which he devoted himself to his scientific work until his death.

A crater on the moon is named in his honor, as is the asteroid 59239 Alhazen.

 

Experimental Scientific Method

Ibn al-Haytham used experimental evidence to check his theories, which was unusual for his time because physics before him was more like philosophy, without experiment. He was the first to introduce experimental evidence as a requirement for accepting a theory, and his Book of Optics was actually a critique of Ptolemy’s book Almagest. A thousand years on, this optics book is still quoted by professors training research students to be factual and not be swayed by opinions or prejudice. Some science historians believe that Snell’s Law, in optics, actually resides in the work of Ibn Sahl and Ibn al-Haytham.

Neuroscientist Rosanna Gorini notes that “according to the majority of the historians al-Haytham was the pioneer of the modern scientific method.” From this point of view, Ibn Al-Haytham developed rigorous experimental methods of controlled scientific testing to verify theoretical hypotheses and substantiate inductive conjectures. Other historians of science place his experiments in the tradition of Ptolemy and see in such interpretations a “tendency to ‘modernize’ Alhazen … [which] serves to wrench him slightly out of proper historical focus.”

 

An aspect associated with Alhazen’s optical research is related to systemic and methodological reliance on experimentation (i’tibar) and controlled testing in his scientific inquiries. Moreover, his experimental directives rested on combining classical physics (‘ilm tabi’i) with mathematics (ta’alim; geometry in particular) in terms of devising the rudiments of what may be designated as a hypothetico-deductive procedure in scientific research. This mathematical-physical approach to experimental science supported most of his propositions in Kitab al-Manazir (The Optics; De aspectibus or Perspectivae) and grounded his theories of vision, light and colour, as well as his research in catoptrics and dioptrics (the study of the refraction of light). His legacy was further advanced through the ‘reforming’ of his Optics by Kamal al-Din al-Farisi (d. ca. 1320) in the latter’s Kitab Tanqih al-Manazir (The Revision of [Ibn al-Haytham’s] Optics).

The concept of Occam’s razor is also present in the Book of Optics. For example, after demonstrating that light is generated by luminous objects and emitted or reflected into the eyes, he states that therefore “the extramission of [visual] rays is superfluous and useless.”

The Camera Obscura

Like many eminent philosophers and mathematicians, Ibn Al-Haytham was a keen observer. While in a room one day he noticed light coming through a small hole made in the window shutters. It fell onto the wall opposite and it was the half-moon shape of the sun’s image during eclipses. He said: ‘The image of the sun at the time of the eclipse, unless it is total, demonstrates that when its light passes through a narrow, round hole and is cast on a place opposite to the hole it takes on the form of a moon-sickle.’

From his experiments, he explained that light travelled in a straight line and when the rays were reflected off a bright subject they passed through the small hole and did not scatter but crossed and reformed as an upside-down image on a flat white surface parallel to the hole. He then established that the smaller the hole, the clearer the picture.

His experimental conclusions were that when the sunlight reached and penetrated the hole, it made a conic shape at the meeting point with the pinhole, and later formed another conic shape in reverse to the first one on the opposite wall in the dark room.

‘Light issues in all directions opposite any body that is illuminated with any light [and of course, also opposite any self-luminous body]. Therefore when the eye is opposite a visible object and the object is illuminated with light of any sort, light comes to the surface of the eye from the light of the visible object.’ (10th-century Ibn al-Haytham from his ‘Book of Optics)

In later stages, these discoveries led to the invention of the camera obscura, and Ibn Al-Haytham built the first camera, a camera obscura or pinhole camera, in history. He went on to explain that we see objects upright and not upside-down, as the camera does, because of the connection of he optic nerve with the brain, which analyses and defines the image.

During his practical experiments, Ibn Al-Haytham often used the term al-Bayt al-Muthim, which was translated into Latin as camera obscura, or dark, private or closed room or enclosed space. Camera is still used today, as is qamara in Arabic which still means a private or dark room.

Many of Ibn Al-Haytham’s works, especially his huge Book of Optics, were translated into Latin by the medieval scholar Gerard of Cremona. This has a profound impact on the 13th-century big thinkers like Roger Bacon and Witelo, and even on the 15th-century works of Leonardo da Vinci.

Today, the camera has gone from the humble beginnings of Ibn-Al-Haytham’s dark front room, the qamara, to become a sophisticated digital process, while the study of optics has blossomed into a whole science covering lasers, optical sectioning of the human retina and researching red bioluminescence in jelly fish.

References

  • Ibn al-Haitham and vision
  • Omar, S.B.(1977), ‘Ibn al-Haytham’s Optics’: Bibliotheca Islamica; Chicago.
  • Lindberg, D.C.(1983), ‘Studies in the History of medieval optics’, Varorium, London.
  • Lindberg, D.C. (1972), ‘Introduction: Optica Thesaurus: Alhazen and Witelo;
  • editor: H. Woolf. Johnson Reprint Corporation, New York, London, p.15.
  • Ibn al-Haitham camera obscura Using holes in Window shutters
  • Durant, W.(1950), ‘The Age of Faith’, Simon and Shuster, New York; p. 288.
  • Baron Carra de Vaux (1921), ‘Les Penseurs de l’Islam’, vol 2, Librairie Paul Geuthner, p.249.

al-Khwarizmi محمد بن موسى الخوارزمي

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One of the first Directors of the House of Wisdom in Bagdad in the early 9th Century was an outstanding Muslim mathematician called Muhammad Al-Khwarizmi. He oversaw the translation of the major Greek and Indian mathematical and astronomy works (including those of Brahmagupta) into Arabic, and produced original work which had a lasting influence on the advance of Muslim and (after his works spread to Europe through Latin translations in the 12th Century) later European mathematics.

The word “algorithm” is derived from the Latinization of his name, and the word “algebra” is derived from the Latinization of “al-jabr”, part of the title of his most famous book, in which he introduced the fundamental algebraic methods and techniques for solving equations.

Perhaps his most important contribution to mathematics was his strong advocacy of the Hindu numerical system, which Al-Khwarizmi recognized as having the power and efficiency needed to revolutionize Islamic and Western mathematics. The Hindu numerals 1 – 9 and 0 – which have since become known as Hindu-Arabic numerals – were soon adopted by the entire Islamic world. Later, with translations of Al-Khwarizmi’s work into Latin by Adelard of Bath and others in the 12th Century, and with the influence of Fibonacci’s “Liber Abaci” they would be adopted throughout Europe as well. Read the rest of this entry »