Ibn Zuhr was one of the greatest physicians and clinicians of the Muslim golden era and has rather been held by some historians of science as the greatest of them. Contrary to the general practice of the Muslim scholars of that era, he confined his work to only one field : medicine. This enabled him to produce works of everlasting fame.

As a physician, he made several discoveries and breakthroughs. He described correctly, for the first time, scabies, the itch mite and may thus be regarded as the first parasitologist. Likewise, he prescribed tracheotomy and direct feeding through the gullet and rectum in the cases where normal feeding was not possible. He also gave clinical descriptions of mediastinal tumors, intestinal phthisis, inflammation of the middle ear, pericarditis, etc.

Abu Marwan Abd al-Malik ibn Zuhr (Arabic: أبو مروان عبد الملك بن زهر‎) (also known as Ibn Zuhr, Avenzoar, Abumeron or Ibn-Zohr) (1091-1161) was an Arab Muslim physician, pharmacist, surgeon, parasitologist, Islamic scholar, and teacher.

Early life

He was born in Seville, and studied at the University of Cordoba. He belonged to the Banu Zuhr family, which produced five generations of physicians, including two female physicians who served the Almohad ruler Abu Yusuf Ya’qub al-Mansur. Ibn Zuhr was also the teacher of Averroes. He began his medical practice and training under his father, Abu’l-Ala Zuhr (d. 1131).

Flight from Seville

Around 1130, he fell out of favour of with the Almoravid ruler, Ali bin Yusuf bin Tashufin, and fled from Seville. He was however, apprehended and jailed in Marrakesh. Later in 1147 when the Almohad dynasty conquered Seville, he returned and devoted himself to medical practice and teaching. He died at Seville in 1161.

Achievements

He is considered the father of experimental surgery, for introducing the experimental method into surgery, introducing the methods of human dissection and autopsy, inventing the surgical procedure of tracheotomy, performing the first parenteral nutrition of humans with a silver needle, discovering the cause of scabies and inflammation, discovering the existence of parasites, and refuting the theory of four humours.

Al-Taisir

Ibn Zuhr’s most famous work is his Al-Taisir, in which he introduced the experimental method into surgery, for which he is considered the father of experimental surgery. He was the first to employ animal testing in order to experiment with surgical procedures before applying them to human patients.  He also performed the first dissections and postmortem autopsies on humans as well as animals.

He invented the surgical procedure of tracheotomy, as he was the first to give a correct description of the tracheotomy operation for suffocating patients. He perfected this surgical procedure through his experiments on a goat. He also performed postmortem autopsies on a sheep during his clinical trials on the treatment of ulcerating diseases of the lungs. He also wrote on the prophylaxis against urinary tract infections and described the importance of dietary management in maintaining the prophylaxis.

He established surgery as an independent field of medicine, by introducing a training course designed specifically for future surgeons, in order that they be qualified before being allowed to perform operations independently, and for defining the roles of a general practitioner and a surgeon in the treatment of a surgical condition.

The Method of Preparing Medicines and Diet

He performed the first parenteral nutrition of humans with a silver needle, and wrote a book on it entitled The Method of Preparing Medicines and Diet.

Anatomy, Physiology, Etiology and Parasitology

During his medical experiments on anatomy and physiology, Ibn Zuhr was the first physician known to have carried out human dissection and postmortem autopsy. He proved that the skin disease scabies was caused by a parasite, which contradicted the erroneous theory of four humours supported by Hippocrates, Galen and Avicenna. The removal of the parasite from the patient’s body did not involve purging, bleeding or any other traditional treatments associated with the four humours. His works show that he was often highly critical of previous medical authorities, including Avicenna’s The Canon of Medicine.

He was one of the first physicians to reject the erroneous theory of four humours, which dates back to Hippocrates and Galen. Avenzoar also confirmed the presence of blood in the body.

Ibn Zuhr was also the first to provide a real scientific etiology for the inflammatory diseases of the ear, and the first to clearly discuss the causes of stridor. He also proved that the skin disease scabies was caused by a parasite.

Anesthesiology

In anesthesiology, modern anesthesia was developed in Islamic Spain by the Muslim anesthesiologists Ibn Zuhr and Abu al-Qasim al-Zahrawi. They were the first to utilize oral as well as inhalant anesthetics, and they performed hundreds of surgeries under inhalant anesthesia with the use of narcotic-soaked sponges which were placed over the face.

Neurology and Neuropharmacology

Ibn Zuhr gave the first accurate descriptions on neurological disorders, including meningitis, intracranial thrombophlebitis, and mediastinal tumours, and made contributions to modern neuropharmacology.

Pharmacopoeia and drug therapy

Ibn Zuhr wrote an early pharmacopoeia, which later became the first Arabic book to be printed with a movable type in 1491.

Ibn Zuhr (and other Muslim physicians such as al-Kindi, Ibn Sahl, Abulcasis, al-Biruni, Avicenna, Averroes, Ibn al-Baitar, Ibn Al-Jazzar and Ibn al-Nafis) developed drug therapy and medicinal drugs for the treatment of specific symptoms and diseases. His use of practical experience and careful observation was extensive.

Biography

Abu al-Qasim was born in the city of El Zahra, six miles northwest of Cordoba, Spain. He was descended from the Ansar Arab tribe who settled earlier in Spain. Few details remain regarding his life, aside from his published work, due to the destruction of El-Zahra during later Spanish-Moorish conflicts. His name first appears in the writings of Abu Muhammad bin Hazm (993 – 1064), who listed him among the greatest physicians of Moorish Spain. But we have the first detailed biography of El-Zahrawi from al-Humaydi’s Jadhwat al-Muqtabis (On Andalusian Savants), completed six decades after El-Zahrawi’s death.

In El-Zahra, he lived most of his life. It is also where he studied, taught and practised medicine and surgery until shortly before his death in about 1013, two years after the sacking of El-Zahra.

Works

Abu al-Qasim was a court physician to the Andalusian caliph Al-Hakam II. He devoted his entire life and genius to the advancement of medicine as a whole and surgery in particular. His best work was the Kitab al-Tasrif. It is a medical encyclopaedia spanning 30 volumes which included sections on surgery, medicine, orthopaedics, ophthalmology, pharmacology, nutrition etc.

In the 14th century, French surgeon Guy de Chauliac quoted al-Tasrif over 200 times. Pietro Argallata (d. 1453) described Abu al-Qasim as “without doubt the chief of all surgeons”. In an earlier work, he is credited to be the first to describe ectopic pregnancy in 963, in those days a fatal affliction. Abu Al-Qasim’s influence continued for at least five centuries, extending into the Renaissance, evidenced by al-Tasrif’s frequent reference by French surgeon Jaques Delechamps (1513-1588).

Page from a 1531 Latin translation by Peter Argellata of El Zahrawi’s treatise on surgical and medical instruments.

Kitab al-Tasrif

Abu al-Qasim’s thirty-chapter medical treatise, Kitab al-Tasrif, published in 1000, covered a broad range of medical topics, including dentistry and childbirth, which contained data that had accumulated during a career that spanned almost 50 years of training, teaching and practice. In it he also wrote of the importance of a positive doctor-patient relationship and wrote affectionately of his students, whom he referred to as “my children”. He also emphasised the importance of treating patients irrespective of their social status. He encouraged the close observation of individual cases in order to make the most accurate diagnosis and the best possible treatment.

Al-Tasrif was later translated into Latin by Gerard of Cremona in the 12th century, and illustrated. For perhaps five centuries during the European Middle Ages, it was the primary source for European medical knowledge, and served as a reference for doctors and surgeons.

Not always properly credited, Abu Al-Qasim’s al-Tasrif described both what would later became known as “Kocher’s method” for treating a dislocated shoulder and “Walcher position” in obstetrics. Al-Tasrif described how to ligature blood vessels before Ambroise Pare, and was the first recorded book to document several dental devices and explain the hereditary nature of haemophilia.

Advances in surgery

Al-Qasim was a surgeon and specialized in curing disease by cauterization. He also invented several devices used during surgery, for the purpose of:

• inspection of the interior of the urethra
• applying and removing foreign bodies from the throat
• inspection of the ear

Al-Qasim also described the use of forceps in vaginal deliveries.

Surgical instruments

In his Al-Tasrif (The Method of Medicine), he introduced his famous collection of over 200 surgical instruments. Many of these instruments were never used before by any previous surgeons. Hamidan, for example, listed at least twenty six innovative surgical instruments that Abulcasis introduced.

Catgut

Abu al-Qasim’s use of catgut for internal stitching is still practised in modern surgery. The catgut appears to be the only natural substance capable of dissolving and is acceptable by the body.

Forceps

In the Al-Tasrif (1000), Abu al-Qasim invented the forceps for extracting a dead fetus, as illustrated in the the Al-Tasrif.^[3]

Ligature

In the Al-Tasrif (1000), Abu al-Qasim introduced the use of ligature for the arteries in lieu of cauterization.

Surgical needle

The surgical needle was invented and described by Abu al-Qasim in his Al-Tasrif (1000).

Other instruments

Other surgical instruments invented by Abu al-Qasim and first described in his Al-Tasrif (1000) include the scalpel, curette, retractor, surgical spoon, sound, surgical hook, surgical rod, and specula.

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Life

Born in Guadix near Granada, he was educated by Ibn Bajjah (Avempace). He served as a secretary for the ruler of Granada, and later as vizier and physician for Abu Yaqub Yusuf, the Almohad ruler of Al-Andalus, to whom he recommended Averroës as his own successor when he retired in 1182. He died in Morocco.

Ibn Tufail was the author of Ḥayy bin Yaqẓan, حي بن يقظان (“Alive son of Awake”): a philosophical romance and allegorical tale of a man who lives alone on an island and who, without contact with other human beings, discovers ultimate truth through a systematic process of reasoned inquiry. Hayy ultimately comes into contact with civilization and religion when he meets Absal. He determines that the trappings of religion, namely imagery and dependence on material goods, are necessary for the multitude in order that they might have decent lives. However, imagery and material goods are distractions from the truth and ought to be abandoned by those whose reason recognizes that they are distractions.

Ibn Tufail drew the name of the tale and most of its characters from an earlier work by Ibn Sina (Avicenna). Ibn Tufail’s book was neither a commentary on nor a mere retelling of Ibn Sina’s work, however, but a new and innovative work in its own right. It reflects one of the main concerns of Muslim philosophers (later also of Christian thinkers), that of reconciling philosophy with revelation. At the same time, the narrative anticipates in some ways both Robinson Crusoe and Rousseau’s Émile. It tells of a child who is nurtured by a gazelle and grows up in total isolation from humans. In seven phases of seven years each, solely by the exercise of his faculties, Hayy goes through all the graduations of knowledge.

The story of Hayy Ibn Yaqzan is similar to the later story of Mowgli in Rudyard Kipling’s The Jungle Book in that a baby is abandoned in a deserted tropical island where he is take care of and fed by a mother wolf.

A Latin translation of the work, entitled Philosophus autodidactus, first appeared in 1671, prepared by Edward Pococke the Younger. The first English translation (by Simon Ockley) was published in 1708.

The astronomer Nur Ed-Din Al Betrugi was a disciple of Ibn Tufail.

He wrote some 450 books on a wide range of subjects, many of which concentrated on philosophy and medicine. His most famous works are The Book of Healing and The Canon of Medicine, which was a standard medical text at many Islamic and European universities up until the 18th century. Ibn Sina developed a medical system that combined his own personal experience with that of Islamic medicine, the medical system of Galen, Aristotelian metaphysics, and ancient Persian, Arabian and Indian medicine. Ibn Sina is regarded as the father of modern medicine, particularly for his introduction of systematic experimentation and quantification into the study of physiology, and for his discovery of the contagious nature of diseases. He is also considered the father of the fundamental concept of momentum in physics.

George Sarton, the father of the history of science, wrote in the Introduction to the History of Science:

“One of the most famous exponents of Muslim universalism and an eminent figure in Islamic learning was Ibn Sina, known in the West as Avicenna (981-1037). For a thousand years he has retained his original renown as one of the greatest thinkers and medical scholars in history. His most important medical works are the Qanun (Canon) and a treatise on Cardiac drugs. The ‘Qanun fi-l-Tibb’ is an immense encyclopedia of medicine. It contains some of the most illuminating thoughts pertaining to distinction of mediastinitis from pleurisy; contagious nature of phthisis; distribution of diseases by water and soil; careful description of skin troubles; of sexual diseases and perversions; of nervous ailments.

Biography

Early life

Ibn Sina’s life is known to us from authoritative sources. A biography, which is widely considered by foremost Arabicists to have been composed by a disciple and later redacted, covers his first thirty years, and the rest are documented by his disciple al-Juzjani, who was also his secretary and his friend.

He was born in Persia around 980 (370 AH) in Afshana, his mother’s home, a small city now part of Uzbekistan. His father, a respected Ismaili scholar, was from Balkh of the Persian province of Khorasan, now part of Afghanistan, and was at the time of his son’s birth the governor of a village in one of the Samanid Nuh ibn Mansur‘s estates. He had his son very carefully educated at Bukhara. According to the Encyclopedia of Islam his father and his brother were influenced by Isma’ili propaganda; he was certainly acquainted with its tenets, but refused to adopt them. Ibn Sina’s independent thought was served by an extraordinary intelligence and memory, which allowed him to overtake his teachers at the age of fourteen.

Ibn Sina was put under the charge of a tutor, and his precocity soon made him the marvel of his neighbours; he displayed exceptional intellectual behaviour and was a child prodigy who had memorized the Quran by the age of 7 and a great deal of Persian poetry as well. From a greengrocer he learned arithmetic, and he began to learn more from a wandering scholar who gained a livelihood by curing the sick and teaching the young.

However he was greatly troubled by metaphysical problems and in particular the works of Aristotle. So, for the next year and a half, he also studied philosophy, in which he encountered greater obstacles. In such moments of baffled inquiry, he would leave his books, perform the requisite ablutions, then go to the mosque, and continue in prayer till light broke on his difficulties. Deep into the night he would continue his studies, and even in his dreams problems would pursue him and work out their solution. Forty times, it is said, he read through the Metaphysics of Aristotle, till the words were imprinted on his memory; but their meaning was hopelessly obscure, until one day they found illumination, from the little commentary by Farabi, which he bought at a bookstall for the small sum of three dirhams. So great was his joy at the discovery, thus made by help of a work from which he had expected only mystery, that he hastened to return thanks to God, and bestowed alms upon the poor.

He turned to medicine at 16, and not only learned medical theory, but also by gratuitous attendance on the sick had, according to his own account, discovered new methods of treatment. The teenager achieved full status as a physician at age 18 and found that “Medicine is no hard and thorny science, like mathematics and metaphysics, so I soon made great progress; I became an excellent doctor and began to treat patients, using approved remedies.” The youthful physician’s fame spread quickly, and he treated many patients without asking for payment.

Adulthood

His first appointment was that of physician to the emir, who owed him his recovery from a dangerous illness (997). Ibn Sina’s chief reward for this service was access to the royal library of the Samanids, well-known patrons of scholarship and scholars. When the library was destroyed by fire not long after, the enemies of Ibn Sina accused him of burning it, in order for ever to conceal the sources of his knowledge. Meanwhile, he assisted his father in his financial labours, but still found time to write some of his earliest works.

When Ibn Sina was 22 years old, he lost his father. The Samanid dynasty came to its end in December 1004. Ibn Sina seems to have declined the offers of Mahmud of Ghazni, and proceeded westwards to Urgench in the modern Uzbekistan, where the vizier, regarded as a friend of scholars, gave him a small monthly stipend. The pay was small, however, so Ibn Sina wandered from place to place through the districts of Nishapur and Merv to the borders of Khorasan, seeking an opening for his talents. Shams al-Ma’ali Kavuus, the generous ruler of Dailam and central Persia, himself a poet and a scholar, with whom Ibn Sina had expected to find an asylum, was about that date (1052) starved to death by his troops who had revolted. Ibn Sina himself was at this season stricken down by a severe illness. Finally, at Gorgan, near the Caspian Sea, Ibn Sina met with a friend, who bought a dwelling near his own house in which Ibn Sina lectured on logic and astronomy. Several of Ibn Sina’s treatises were written for this patron; and the commencement of his Canon of Medicine also dates from his stay in Hyrcania.

Ibn Sina subsequently settled at Rai, in the vicinity of modern Tehran, (present day capital of Iran), the home town of Rhazes; where Majd Addaula, a son of the last Buwayhid emir, was nominal ruler under the regency of his mother (Seyyedeh Khatun). About thirty of Ibn Sina’s shorter works are said to have been composed in Rai. Constant feuds which raged between the regent and her second son, Amir Shamsud-Dawala, however, compelled the scholar to quit the place. After a brief sojourn at Qazvin he passed southwards to Hamadãn, where another Deylamite emir had established himself. At first, Ibn Sina entered into the service of a high-born lady; but the emir, hearing of his arrival, called him in as medical attendant, and sent him back with presents to his dwelling. Ibn Sina was even raised to the office of vizier. The emir consented that he should be banished from the country. Ibn Sina, however, remained hidden for forty days in a sheikh’s house, till a fresh attack of illness induced the emir to restore him to his post. Even during this perturbed time, Ibn Sina persevered with his studies and teaching. Every evening, extracts from his great works, the Canon and the Sanatio, were dictated and explained to his pupils. On the death of the emir, Ibn Sina ceased to be vizier and hid himself in the house of an apothecary, where, with intense assiduity, he continued the composition of his works.

Meanwhile, he had written to Abu Ya’far, the prefect of the dynamic city of Isfahan, offering his services. The new emir of Hamadan, hearing of this correspondence and discovering where Ibn Sina was hidden, incarcerated him in a fortress. War meanwhile continued between the rulers of Isfahan and Hamadãn; in 1024 the former captured Hamadan and its towns, expelling the Tajik mercenaries. When the storm had passed, Ibn Sina returned with the emir to Hamadan, and carried on his literary labours. Later, however, accompanied by his brother, a favourite pupil, and two slaves, Ibn Sina escaped out of the city in the dress of a Sufi ascetic. After a perilous journey, they reached Isfahan, receiving an honourable welcome from the prince.

Later life

Avicenna’s tomb in Hamedan, Iran

The remaining ten or twelve years of Ibn Sina’s life were spent in the service of Abu Ja’far ‘Ala Addaula, whom he accompanied as physician and general literary and scientific adviser, even in his numerous campaigns.

During these years he began to study literary matters and philology, instigated, it is asserted, by criticisms on his style. He contrasts with the nobler and more intellectual character of Averroes. A severe colic, which seized him on the march of the army against Hamadãn, was checked by remedies so violent that Ibn Sina could scarcely stand. On a similar occasion the disease returned; with difficulty he reached Hamadãn, where, finding the disease gaining ground, he refused to keep up the regimen imposed, and resigned himself to his fate.

His friends advised him to slow down and take life moderately. He refused, however, stating that: “I prefer a short life with width to a narrow one with length”. On his deathbed remorse seized him; he bestowed his goods on the poor, restored unjust gains, freed his slaves, and every third day till his death listened to the reading of the Qur’an. He died in June 1037, in his fifty-eighth year, and was buried in Hamedan, Iran.

Works

Scarcely any member of the Muslim circle of the sciences, including theology, philology, mathematics, astronomy, physics, and music, was left untouched by the treatises of Ibn Sina. This vast quantity of works – be they full-blown treatises or opuscula – vary so much in style and content (if one were to compare between the ‘ahd made with his disciple Bahmanyar to uphold philosophical integrity with the Provenance and Direction, for example) that Yahya (formerly Jean) Michot has accused him of “neurological bipolarity”.

Ibn Sina wrote at least one treatise on alchemy, but several others have been falsely attributed to him. His book on animals was translated by Michael Scot. His Logic, Metaphysics, Physics, and De Caelo, are treatises giving a synoptic view of Aristotelian doctrine, though the Metaphysics demonstrates a significant departure from the brand of Neoplatonism known as Aristotelianism in Ibn Sina’s world; Arabic philosophers have hinted at the idea that Ibn Sina was attempting to “re-Aristotelianise” Muslim philosophy in its entirety, unlike his predecessors, who accepted the conflation of Platonic, Aristotelian, Neo- and Middle-Platonic works transmitted into the Muslim world.

The Logic and Metaphysics have been printed more than once, the latter, e.g., at Venice in 1493, 1495, and 1546. Some of his shorter essays on medicine, logic, etc., take a poetical form (the poem on logic was published by Schmoelders in 1836). Two encyclopaedic treatises, dealing with philosophy, are often mentioned. The larger, Al-Shifa’ (Sanatio), exists nearly complete in manuscript in the Bodleian Library and elsewhere; part of it on the De Anima appeared at Pavia (1490) as the Liber Sextus Naturalium, and the long account of Ibn Sina’s philosophy given by Muhammad al-Shahrastani seems to be mainly an analysis, and in many places a reproduction, of the Al-Shifa’. A shorter form of the work is known as the An-najat (Liberatio). The Latin editions of part of these works have been modified by the corrections which the monastic editors confess that they applied. There is also a حكمت مشرقيه (hikmat-al-mashriqqiyya, in Latin Philosophia Orientalis), mentioned by Roger Bacon, the majority of which is lost in antiquity, which according to Averroes was pantheistic in tone.

Sciences

Medicine

A Latin copy of the Canon of Medicine, dated 1484, located at the P.I. Nixon Medical Historical Library of The University of Texas Health Science Center at San Antonio.

About 100 treatises were ascribed to Ibn Sina. Some of them are tracts of a few pages, others are works extending through several volumes. The best-known amongst them, and that to which Ibn Sina owed his European reputation, is his 14-volume The Canon of Medicine, which was a standard medical text in Europe and the Islamic world up until the 18th century. The book is known for its introduction of systematic experimentation and quantification into the study of physiology, and for the discovery of contagious diseases. It classifies and describes diseases, and outlines their assumed causes. Hygiene, simple and complex medicines, and functions of parts of the body are also covered. In this, Ibn Sina is credited as being the first to correctly document the anatomy of the human eye, along with descriptions of eye afflictions such as cataracts. It asserts that tuberculosis was contagious, which was later disputed by Europeans, but turned out to be true. It also describes the symptoms and complications of diabetes. Both forms of facial paralysis were described in-depth. In addition, the workings of the heart as a valve are described.

A copy of the Canon of Medicine, dated 1593

An Arabic edition of the Canon appeared at Rome in 1593, and a Hebrew version at Naples in 1491. Of the Latin version there were about thirty editions, founded on the original translation by Gerard de Sablonetta. In the 15th century a commentary on the text of the Canon was composed. Other medical works translated into Latin are the Medicamenta Cordialia, Canticum de Medicina, and the Tractatus de Syrupo Acetoso.

It was mainly accident which determined that from the 12th to the 18th century, Ibn Sina should be the guide of medical study in European universities, and eclipse the names of Rhazes, Ali ibn al-Abbas and Averroes. His work is not essentially different from that of his predecessor Rhazes, because he presented the doctrine of Galen, and through Galen the doctrine of Hippocrates, modified by the system of Aristotle, as well as the Indian doctrines of Sushruta and Charaka.^[12] But the Canon of Ibn Sina is distinguished from the Al-Hawi (Continens) or Summary of Rhazes by its greater method, due perhaps to the logical studies of the former.

The work has been variously appreciated in subsequent ages, some regarding it as a treasury of wisdom, and others, like Averroes, holding it useful only as waste paper. In modern times it has been seen of mainly historic interest as most of its tenets have been disproved or expanded upon by scientific medicine. The vice of the book is excessive classification of bodily faculties, and over-subtlety in the discrimination of diseases. It includes five books; of which the first and second discuss physiology, pathology and hygiene, the third and fourth deal with the methods of treating disease, and the fifth describes the composition and preparation of remedies. This last part contains some personal observations.

He is, like all his countrymen, ample in the enumeration of symptoms, and is said to be inferior to Ali in practical medicine and surgery. He introduced into medical theory the four causes of the Peripatetic system. Of natural history and botany he pretended to no special knowledge. Up to the year 1650, or thereabouts, the Canon was still used as a textbook in the universities of Leuven and Montpellier.

In the museum at Bukhara, there are displays showing many of his writings, surgical instruments from the period and paintings of patients undergoing treatment. Ibn Sina was interested in the effect of the mind on the body, and wrote a great deal on psychology, likely influencing Ibn Tufayl and Ibn Bajjah. He also introduced medical herbs.

Alchemy

In alchemy, Ibn Sina discredited the theory of transmutation of substances believed by some alchemists:

“Those of the chemical craft know well that no change can be effected in the different species of substances, though they can produce the appearance of such change.”

Aromatherapy

Ibn Sina used steam distillation to produce the first essential oils. As a result, he is regarded as a pioneer of aromatherapy.

Astronomy

In 1070, Abu Ubayd al-Juzjani, a pupil of Ibn Sina, claimed that his teacher Ibn Sina had solved the equant problem in Ptolemy’s planetary model.

Chemistry

In chemistry, steam distillation was invented by Ibn Sina in the early 11th century, which he used to produce essential oils.

Earth sciences

Ibn Sina wrote on the earth sciences in The Book of Healing. In geology, he hypothesized two causes of mountains:

“Either they are the effects of upheavals of the crust of the earth, such as might occur during a violent earthquake, or they are the effect of water, which, cutting itself a new route, has denuded the valleys, the strata being of different kinds, some soft, some hard… It would require a long period of time for all such changes to be accomplished, during which the mountains themselves might be somewhat diminished in size.”

Physics

In physics, Ibn Sina was the first to employ an air thermometer in his scientific experiments.

In mechanics, Ibn Sina developed an elaborate theory of motion, in which he made a distinction between the inclination and force of a projectile, and concluded that motion was a result of an inclination (mayl) transferred to the projectile by the thrower, and that projectile motion in a vacuum would not cease. He viewed inclination as a permanent force whose effect is dissipated by external forces such as air resistance. His theory of motion was thus consistent with the concept of inertia in Newton’s first law of motion. Ibn Sina also referred to mayl to as being proportional to weight times velocity, a precursor to the concept of momentum in Newton’s second law of motion. Ibn Sina’s theory of mayl was further developed by Jean Buridan in his theory of impetus.

In optics, Ibn Sina provided a sophisticated explanation for the rainbow phenomenon. Carl Benjamin Boyer described Ibn Sina’s theory on the rainbow as follows:

“Independent observation had demonstrated to him that the bow is not formed in the dark cloud but rather in the very thin mist lying between the cloud and the sun or observer. The cloud, he thought, serves simply as the background of this thin substance, much as a quicksilver lining is placed upon the rear surface of the glass in a mirror. Ibn Sina would change the place not only of the bow, but also of the color formation, holding the iridescence to be merely a subjective sensation in the eye.”

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