Based on the book Introduction to the History of Science by George Sarton (provided with photos and portraits)Edited and prepared by Prof. Hamed A. Ead

The Time of Al-Biruni

First Half of Eleventh Century

The great leaders were so many - Ibn Yunus, Ibn al-Haitham, Al-Biruni, Ibn Sina, Ali ibn Isa, al-Karkhi, Ibn Gabirol (all Muslim except the last, who was Jewish) - that, for a moment at least, the historian is bewildered. Yet, however distinguished all of those men, and many others who will be named presently, two stand out head and shoulders above the others: al-Biruni and Ibn Sina (Avicenna). It was chiefly because all of them that this period was one of such excellence and distinction. These two men, who by the way, knew one another, were extremely different. Al-Biruni represents the more adventurous and critical spirit, Ibn Sina the synthetic spirit, al-Biruni was more of a discoverer, and in that respect he came nearer to the modern scientific ideal; Ibn Sina was essentially an organizer, an encyclopedist, a philosopher. Both, even the latter, were primarily men of science, and it would be difficult to choose between them but the accidental fact that al-Biruni's life covered more fully the present period and thus may be said to represent it more completely. Ibn Sina was only 20 at the beginning of the century, and his life was ultimately cut short in 1037. Al-Biruni's first important work appeared about 1000 and he lived until 1048. Thus his time of activity and the first half of the eleventh century are not identical periods, and we are fully justified (more fully so than in almost every short case) in calling it the Time of al-Biruni.

Muslim Mathematics and astronomy

It is almost like passing from the shade to the open sun and from a sleepy world into one tremendously active. For the sake of convenience, I divide Muslim mathematicians into three groups: those of the West, those of Egypt, who occupied, so to speak, an intermediate position, and those of the East. This is also a logical division, for though communications between the eastern and western ends of the Islam were frequent (there were a number of itinerant scholars to whom the universality of Islam seems to have been a continual provocation to move on from place to place), it is clear that local influences were felt more constantly and to greater advantage.

The greatest astronomer and trigonometrician of the time was Ibn Yunus, who lived in Cairo. Every thing considered, he was perhaps the greatest Muslim astronomer, and the Fatimid rules of Egypt gave him magnificent opportunities. Indeed, under the sixth Fatimid, al-Hakim, a sort of academy of science (Dar al-Hikma) had been established in Cairo, and, had been the case for the academy founded by al-Ma'mun in Bagdad two centuries earlier, an observatory was an essential part of it. Ibn Yunus made excellent use of these exceptional facilities to measure more accurately the number of astronomical constants and to compile improved tables named after his patron, the Hakemite tables. He contributed his share to the development of trigonometry, discovering new solutions of spherical problems and introducing the first of the prosthapheretical formulas. His colleague in al-Hakim's academy, Ibn al-Haitham, better known as a physicist, was also a great astronomer and mathematician. He made a curious attempt to measure the height of the atmosphere on the basis of his knowledge and of the length of twilight. He solved al-Mahani's equation and the so-called Alhazen's problem by means of intersecting conics.

The mathematicians of the East were so numerous, and though they could boast no man comparable in his branch of learning to Ibn Yunus, their work was generally on a very high level and full of originality. Kushyar ibn Labban especially interested in trigonometry, he made a deeper study on the tangent function and compiled new astronomical tables which were sooner translated into Persian. He also wrote on astrology and arithmetic. Ibn al-Husain investigated the classical problems of the Greek geometry (for example, the duplication of the cube) and tried to solve them by purely geometrical means. Abu-l-Jud was also a geometer; he made a special study on the regular heptagon and enneagon and of those problems which can not be solved by means of ruler and compass alone; he tried to classify equations with reference to conic sections, he is one of the mathematicians who prepared the work of Omar al-Khayyam in the following period. The greatest of them all, al-Karkhi was chiefly an arithmatician and algebraist. He solved a number of Diophantine problems and invented a series of new one. His work contains many of the original features, but the most extra-ordinary of these is the systematic neglect of Hindu numerals. No numerals are used, the names of the numerals being written in full. It is as if al-Karkhi had considered the use of Hindu numerals as vulgar and non-scientific. Al-Nasawi wrote a practical arithmetic in Persian and later translated it into Arabic. He explained the Hindu methods and applied them to difficult numerical problems; in these computations the sexagesimal fractions introduced by astronomical measurements were replaced by decimal fractions. Ibn Tahir wrote also arithmetical book of a practical nature; he showed how to solve the complicated inheritance problems entailed by the Muslim fondness for juridical niceties. To al-Biruni we owe the best mediaeval account of Hindu numerals. He composed an astronomical encyclopedia and a general treatise on mathematics , astronomy, and astrology. He was deterred neither by formidable computations nor by the most difficult geometrical problems of his time, those called after him Albirunic problems. He introduced a simplified method of stereographic projection. As we would expect, the philosophical aspects of mathematics were more to ibn Sina than the more technical details. We already know that in spite of his encyclopedic activities Ibn Sina found time to carry on a number of astronomical observations and to improve the observational technique.

I named these Eastern mathematicians, as well as possible, in chronological order. This does not, perhaps, bring out with sufficient clearness the full complexity of their activities. In the first place, observe that, I did not mention a single astrologer; only one named in this section flourished not in the East, but in the orthodox Tunis, where there was much less freedom of thought. In the second place, if we leave out of account the astronomical work, which was determined by practical necessities, we find that there were two distinct streams of mathematical thought: the one theoretical represented by Ibn al-Husain, Abu-l-Jud, and al-Karkhi, the other, more practical, represented by al-Nasawi and Ibn Tahir. Al-Biruni and Ibn Sina can not be included in that classification, for they were equally in the most abstruse and in the most practical questions; they had no contempt for humble means, for there are no small matters for great minds.

Muslim Physics, Chemistry and Technology

Contemporary accounts of Muslim achievements must be started with Ibn al-Haitham, who flourished in Cairo at the beginning of the century. He was not only the greatest Muslim physicist, but by all means the greatest of mediaeval times. His researches on geometrical and physiological optics were the most significant to occur between ancient times and the sixteenth century. His description of the eye and his explanation of vision were distinct improvements. Muslim scientists had developed a great interest in the determination of specific gravity. Al-Biruni continued that tradition and measured the density of 18 precious stones and metals with remarkable accuracy. He observed that the speed of light is incomparably greater than the of sound. Ibn Sina investigated all the fundamental questions of physics which could be formulated finite. His study of music was especially important and far ahead of the contemporary Latin work. He described the doubling with octave, the fourth and the fifth, and even with the third.

A college of Ibn al-Haitham in the Cairo academy, Masawaih al-Mardini, explained the preparation empyreumatic oils. Ibn Sina intertained original views on chemistry; he did not share the common belief of Muslim alchemists that the coloring or bronzing of metals affected their substance, he thought that the differences between metals were to deep to permit their transmutation. An important alchemical treatise was composed in 1034 by al-Kathi.

Muslim or Arabic Medicine

There are so many that I must again divide them into three groups. Those of Spain, those of Egypt, and those of the East.

Spain: Al-Karmani has already been mentioned. He was at once a mathematician and a surgeon. Ibn al-Wafid composed a treatise on simple drugs, which is partly extant in Latin, and a treatise on Balneography. To these two Muslims may be added the Jew, Ibn Janah, who flourished in Saragossa and wrote there in Arabic, a book on simple remedies.

Egypt: Not less than four great Physician enjoyed the patronage of the Fatimid rulers of Egypt. Masawaih al-Mardini (Mesue the Younger) compiled a large dispensatory which was immensely popular in mediaeval Europe. For centuries it remained the standard work on the subject. Ammar was perhaps the most original oculist of Islam, but his work was superseded by that of the Eastern contemporary, Ali ibn Isa. The surgical part of Ammar's ophthalmologic treatise is particularly important. The third of these physicians, Ibn al-Haitham (Alhazen) has already been dealt with many times; he must be remembered her because of his studies in physiological optics. Ali ibn Ridwan wrote various commentaries on Greek medicine, of which the best known was one on Galen's Ars prava; he also wrote a treatise on hygiene with special reference to Egypt. It should be noted that Masawaih was a monophysite Christian; the others were Muslims.

East: The greatest physician of the time and one of the greatest of all times was Ibn Sina (Avicenna). His enormous medical encyclopedia, the Qanun (Canon), remained the supreme authority, not simply in Islam but also in Christendom, for some six centuries. It contained a number of original observations, but its hold on the people was chiefly due to its systematic arrangement and its very dogmatism. Ibn Sina was not as great a physician as Galen, but he had very much the same intellectual qualities and defects and his ascendancy was largely based upon the same grounds. He had the advantage over Galen being able to take into account the vast experience of Muslim physicians.

Ibn al-Taiyib wrote commentaries on Greek medicine. Abu Sa'id Ubaid Allah, of the famous Bakhtyashu family, wrote treatise on love-sickness and discussed the philosophical terms used by physicians. Ibn Butlan compiled the so-called Tables of Health, a medical summary, divided into 15 vertical columns; he is perhaps the originator of that typical form of synopsis. Finally Ali ibn Isa (Jesu Haly) was the author of the most famous ophthalmologistical treatise written in Arabic, it is very remarkable that not than three of these physicians, that is more than half of them, were Christians living in Bagdad: Ibn al-Taiyib, Abu Sa'id Ubaid Allah, and Ibn Butlan. This testifies for the faithfulness of the Christian community of Bagdad and the toleration of the Muslim rulers. It should be added that the other physicians, i.e., the Muslims, were far more important.

Muslim Mathematics and Astronomy

Muslim Mathematics of the West

AL-KARMANI

Abu Hakam Amr (or Omar) ibn Abd al-Rahman ibn Ahmed ibn Ali al-Karmani (that is of Carmona). Born in Cordova, died in Saragossa. Spanish-Muslim mathematician and surgeon. Disciple of Maslam ibn Ahmed (q. v., second half of tenth century). It is he (or else the latter) who introduced the writings of the Brethren of Purity into Spain.

Suter: Die Mathematiker und Astronomen der Araber (105, 1900).

IBN AL-SAMH

Abu al-Qasim Asbagh ibn Mohammed ibn al-Samh. Flourished at Granada; died May 29, 1035, at the age of 56. Hispano-Muslim mathematician and astronomer. He wrote treatises on commercial arithmetic (al-mu'amalat), on two mental calculus (hisab al-hawa'i), on the nature of numbers, two on geometry, two on astrolabe, its use and construction. His main work seems to have been the compilation of astronomical tables, according to the Siddhanta method (for which see my notes on Mohammed ibn Ibrahim al-Fazari second half of eighth century), together with theoretical explanations (c. 1025).

H. Suter: Mathematiker (85, 1900; 168, 1902).

IBN ABI-L-RIJAL

In Latin, Abenragel (also Albohazen, Alboacen, which was more correct, for Abenragel was his father's name, rather than his own). Abu-l-Hasan Ali ibn Abi-l-Rijal al-Saibani al-Katib al-Maghribi. Born in Cordova or else where in Spain or in northern Africa, flourished in Tunis some time about 1016 to 1040, died after 1040. Muslim astrologer. His main work is the "distinguished book on horoscopes from the constellations" (al-bari fi ahkam al-nujum). It was translated by Judah ben Moses from Arabic into Castilian, then from Castilian into Latin by Aegidius de Tebaldis and Petrus de Regio. He wrote a physiognomic treatise on Naevi.

H. Suter: Die Mathematiker und Astronomen der Araber (100, 1900; Nachtrage, 172, 1902); encyclopedia of Islam (vol. 2, 356, 1916).

IBN AL-SAFFAR

Abu-l-Qasim Ahmed ibn Abdallah ibn Omar al-Ghafiqi, best known under the name of Ibn al-Saffar, meaning son of coppersmith. Flourished at Cordova, toward the end of his life he retired in Denia and died there in 1035. Hispano-Muslim mathematician and astronomer. He wrote a treatise on the astrolabe and compiled tables according to the Siddhanta method.

H. Suter: Mathematiker (86, 225, 1900; 169, 1902).

Muslim Mathematics of Egypt

IBN YUNUS

Abu Hasan Ali ibn abi Sa'id Abd al-Rahman ibn Ahmed ibn Yunus (or Ibn Yunus) al-Sadafi al-Misri. Died in Cairo, 1009 (not 1008). The date of his birth is unknown, but his father died in 958-59. Perhaps the greatest Muslim astronomer. A well equipped observatory in Cairo enabled him to prepare improved astronomical tables. Begun c. 990 by order of the Fatimid caliph al-Aziz (975-996), they were completed in 1007 under the latter's son al-Hakim (996-1020) and are called after him the Hakemite Tables (al-zij al-kabir al-Hakimi). They contain observations of eclipses and conjunctions, old and new, improved values of astronomical constants (inclination of the ecliptic, 23o 35`; longitude of the sun's apogee, 86o 10`; solar parallax reduced from 3` to 2`; precession, 51.2`` a year, no allusion to trepidation) and accounts of the geodetic measurements carried on order by al-Ma'mun (q. v., first half of ninth century.)

His contributions to trigonometry, though less important than those of Abu-l-Wafa; are considerable. He solved many problems of spherical astronomy by means of orthogonal projections. He introduced the first of those prosthapheretical formulae which were indispensable before the invention of the logarithms, namely, the equivalent of

cosacosb =1/2 [cos (a - b) + cos (a +b)].

Approximate value of sin 1o = 1.8/3.9 sin (9/8)o + 2.16/3.15 sin(15/16)o

Ibn Yunus's observatory was a part of Hall of Wisdom (Dar al-hikma, abode of wisdom) founded in Cairo by the Fatimids. This institution, which lasted from 1005 to the end Fatimid regime (1171), might be considered the second Muslim academy of science, the first being that founded by al-Ma'mun in Bagdad almost two centuries earlier.

Suter: Encyclopaedia of Islam (vol. 2, 428, 1918).

Muslim Mathematics of East

AL-BIRUNI

Abu-Raihan Mohammed ibn Ahmed al-Biruni. Born in Khwarizm (Khiva) in 973 sojourned a considerable time in India; died in 1048, probably at Ghazna in Sijistan (Afghanistan). He was by birth a Persian and a Shi'ite; his religion was tempered with agonistic tendencies, but his national, anti-Arabic feelings remained very strong until the end. Traveler, mathematician, philosopher, astronomer, geographer, encyclopedist. One of the very greatest of Islam, and, all considered, one of the greatest of all times. His critical spirit, toleration, love of truth, and intellectual courage were almost without parallel in mediaeval times. He claimed that the phrase "Allah is omniscient" does not justify ignorance.

He wrote, in Arabic, a number of books on geographical, mathematical, and astronomical subjects. His main works were: (1) the "Chronology of ancient nations" or "Vestige of the past" (Kitab al-athar al-baqiya ani-l-qurun al-khaliya), written in 1000 and dealing chiefly with the calendars and ears of various peoples; (2) an account on India (Ta'rikh al-Hind) composed in Ghazna c. 1030; (3) an astronomical encyclopedia, the Mas,udic canon (al-qanon al-Mas'udi fi-l-hai'a wal-nujum), so-called because it was dedicated in 1030 to the Ghaznawid sultan Mas'ud; (4) a summery on mathematics, astronomy, and astrology (Al-tafhim li-awa'il sina'at al-tanjim). His description of Brahmanical India was based upon a deep study of the country and its people. He had been charmed by Hindu philosophy, especially by the Bhagavadgita. He translated from Sinskrit into Arabic (e. g., two of Varahamihira's works, q. v., first half of sixth century), and on the other hand, transmitted Muslim knowledge to the Hindus.

He gave a clear account (the best mediaeval account) of Hindu numerals (principle of position). Sum a geometric progression apropos of the chess game; it led to the following number: 1616 -1 = 18, 446, 744, 073, 709, 551, 916. Trisection of the angles and other problems which can not be solved with ruler and compass alone (Albirunic problems). Simplified stereographic projection, similar to that first published by G.B. Nicolosi di Paterno in 1600 (Isis, V, 498).

Accurate determination of latitudes. Determination of longitudes. Geodetic measurements. Al-Biruni discussed the question whether the earth rotates around its axis or not, without reaching a definite conclusion.

Investigations on specific gravity. Remarkably accurate determination of the specific density of 18 precious stones and metals. As compared to the speed of sound, that of light is immense. The work of natural springs and "artesian" wells is explained by the hydrostatic principle of communicating vessels.

Description of monstrosities, including what we call "Siamese" twins.

The Indus valley must be considered as ancient sea basin filled up with alluvions.

H. Suter and E. Wiedemann: Uber al-Biruni (Erlangen, 1920. Quoted above). Carra de Vaux: Penseur de l'Islam (vol. 2, 1921, passim).

KUSHYAR IBN LABBAN

Abu-l-Hasan Kushayr ibn Labban ibn Bashahri al-Jili (i. e., from Jilan, south of the Caspian Sea). Flourished c. 971-1029; his main work was probably done about the beginning of the eleventh century. Persian mathematician and astronomer, writing in Arabic. He seems to have taken an important part in the elaboration of trigonometry. For example, he continued the investigations of Abu-l-Wafa, the devoted much space to this in his tables, al-zij al-jami wa-l-baligh (the comprehensive and mature tables), which were translated into Persian before the end of the century. He wrote also an astrological introduction and an arithmetic treatise (extant to Hebrew).

H. Suter: Mathematiker und Astronomen der Araber (83, 235, 1900; 168, 1902).

IBN AL-HUSAIN

Abu Ja'far Mohammed ibn al-Husain. Flourished not long after al-Khujandi (q. v., second half of the tenth century). Mathematician. He wrote a memoir on rational right angled triangles and another on the determination of two mean proportionals between two lines by a geometrical method (vs. kinematic method), i. e., by the use of what the Muslims called "fixed geometry", al-handasa al-thabit. Solution of the equation

x2 + a = y2.

Suter: Die Mathematiker und Astronomen der Araber (80, 1900; Nachtrage, 168, 1902).

ABU-L-JUD

Abu-l-Jud Mohammed ibn al-Lith, contemporary of al-Biruni. Mathematician. Solution of al-Birunic problems by means of intersecting conics. Regular heptagon and enneagon. Classification of equations and their reduction to conic sections.

Suter: Die Mathematiker und Astronomen der Araber (79, 1900).

AL-KARKHI

Abu Bakr Mohammed ibn al-Hassan (or Husain) al-Hasib (the calculator) al-Karkhi, meaning of Karkh, a suburb of Bagdad. Flourished in Bagdad during the vizierate of Abu Ghakib Mohammed ibn Khalaf Fakhr al-mulk (glory of the realm), who died in 1016; he died himself c. 1019 to 1029. One of the greatest Muslim mathematicians. His book on arithmetic (the sufficient on calculation, alkafi fi-l-hisab) is based chiefly of the Greek and Hellenistic knowledge. No numerals of any kind are used, the names of the numbers being written in full. Casting out of the nines and elevens.

If r < (2a + 1), [(a2 + r)] ~ a + r/(2a + 1).

His algebra called (al-fakhri) in honor of the vizier is largely based on Diophantos. Complete solutions of quadratic equations (with proofs; two roots considered if positive and if not null). Reduction of equations of the type ax2p + bxp = c to quadratic equations. Addition and subtraction of radicals. Summation of series. Solution of Diophantine equations (including 25 problems not found in Diophantos). Al-Karkhi's neglect Hindu mathematics was such that it must have been systematic.

H. Suter: Encyclopaedia of Islam (vol. 2, 764, 1925. Very little).

AL-NASAWI

Abu-l-Hasan Ali ibn Ahmed al-Nasawi. From Nasa, Khurasan. Flourished under the Buwayhid sultan Majd al-dawla, who died in 1029-30, and under his successor. Persian mathematician. He wrote a practical arithmetic in Persian, before 1030, and later under Majd al-dawla's successor an Arabic translation of it, entitled the "Satisfying (or Convincing) on Hindu Calculation" (al-muqni fi-l-hisab al hindi). He also wrote on Archemedes's lemnata and Menelaos's theorem (Kitab al-ishba, satiation). His arithmetic explains the division of fractions and the extraction of square and cubic roots (square root of 57,342; cubic root of 3, 652, 296) almost in the modern manner. It is remarkable that al-Nasawi replaces sexagesimal by decimal fractions, e. g.,

Suter: Die Mathematiker und Astronomen der Araber (96, 1900) Uber das Rechenbuch des Ali ben Ahmed el-Nasawi (Bibliotheca Mathematica, vol. 7, 113-119, 1906).

Muslim Physics, Chemistry and Technology

IBN AL-HAITHAM

Latin name: Alhazen. Abu Ali al-Hasan ibn al-Hasan (or al-Husain) ibn al-Haitham. Born c. 965 in Basra, flourished in egypt under al-Hakim (996 to 10200 died in Cairo in 1039 or soon after. The greatest Muslim physicist and one of the greatest students of optics of all the times. He was also an astronomer, a mathematician, a physician, and he wrote commentaries on Aristotle and Galen.

The Latin translation of his main work, the Optics (kitab al-manazir), exerted a great influence upon Western science (R. Bacon; Kepler). It showed a great progress in the experimental method. Research in catoptrics: spherical and parabolic mirrors, spherical aberration; in dioptrics: the ratio between the angle and incidence and refraction does not remain constant; magnifying power of a lens. study of atmospheric refraction. The twilight only ceases or begins when the sun is 19o below the horizon; attempt to measure the height of the atmosphere on that basis. Better description of the eye, and better understanding of vision, though ibn al-haitham considered the lens as the sensitive part; the rays originate in the object seen, not in the eye. Attempt to explain binocular vision. Correct explanation of the apparent increase in the size the sun and the moon when near the horizon. earliest use of the camera obscura.

The catoptrics contain the following problem, known as Alhazen's problem: from two points of the plane of a circle to draw lines meeting at point of the circumference and making equal angles with the normal at that point. It leads to an equation of the fourth degree. Alhazen solved it by the aid of an hyberpola intersecting a circle. He also solved the so-called al-Mahani's (cubic) equation (q. v., second half of the ninth century) in a similar (Archimedian) manner.

Suter: Die Mathematiker und Astronomen der Araber (91-95, Nachtrage, 169, 1902).

AL-KATHI

Abu-l-Hakim Mohammed ibn Abd al-Malik al-Salihi al-Khwarizmi al-Kathi. Flourished in Bagdad c. 1034. Muslim Chemist, he wrote, in 1034, a treatise on alchemy entitled "Essence of the Art and Aid to the Workers" (Ain al-san'a wa awn-al-sana'a), strikingly similar in some respects to the "Summa perfectionis magisterii" of the Latin Geber (for which see my notes on Jabir, second half of eighth century).

H. E. Stapleton and R. F. Azo: Alchemical Equipments in the Eleventh century (Memories of Asiatic Society of Bengal, vol. 1, 47-70, 1 pl., Calcutta, 1905. Containing Arabic text, an analysis of it, and an introduction; very important).

Muslim (or Arabic) Medicine

Arabic-Writing physicians of the West

IBN AL-WAFID

Latin name: Abenguefit. Abu-l- Mutarrif abd al-Rahman ibn Mohammed ibn Abd al-Karim ibn Yahya ibn al-Wafid al-Lakhmi. From Toledo, where he flourished; born 997, died c. 1074. Hispano-Muslim physician, Pharmacologist. His main work, on simple drugs (Kitab al-adwaiya al-mufrada), based on Galen and Discorides and also on personal investigations, is partly extant in a Latin translation. He preferred to use dietetic measures, and, if drugs were needed, to use the simplest ones. He advised a method of investigating the action of the drugs. He also wrote a balneotherapy.

C. Brocklmann: Arabischen Litteratur (vol. 1, 485, 1898. Two Arabic manuscripts mentioned).

Arabic-Writing physicians of Egypt

MASAWIAH AL-MARDINI

Mesue the Younger. Masawaih al-Mardini, from Mardin in Upper Mesopotamia. Flourished in Bagdad, later at the court of the Fatimid caliph al-Hakim in Egypt, where he died in 1015 at the age of ninety. Physician. Jacobite Christian. He wrote book on purgatives and emetics (De medicins laxativis) and on the complete pharmacopoeia in 12 parts called the Antidotarium sive Grabadin medicamentorum, based on Muslim knowledge. The last-named work was immensely popular. It remained for centuries the standard text-book of pharmacy in the West, and Mesue was called "pharmacopoeorum evabgelista". Distillation of empyreumatic oils.

There is still a third Mesue (q. v., first half of thirteenth century), author of a treatise on surgery.

Neuburger: Geschichte der Medizin (vol. 2, 226-227, 1911).

AMMAR

Latin name: Canamusali. Abu-l-Qasim Ammar ibn Ali al-Mawsili. From Mawsil in Iraq; flourished in Egypt in the reign of al-Hakim, who ruled from 996-1020. Physician. The most original of Muslim oculists, His work was eclipsed by that of his contemporary Ali ibn Isa, which was more comprehensive. His summary on the treatment of the eye (Kitab al-muntakhab fi ilaz al-ain) contains many clear descriptions of diseases and treatments, arranged in logical order. The surgical part is especially important.

E. Mittwoch: Encyclopaedia of Islam (vol. 1, 332, 1910).

ALI IBN RIDWAN

Abu-l-Hasan Ali ibn Radwan ibn Ali ibn Ja'far al-Misri. Born in Jiza near Cairo, c. 998. Flourished in Cairo and died there in 1061 or in 1067. Astrologer. physician. The author of many medical writings of which the most popular was his commentary on Galen'a Ars prava, which was translated by Gerardo Cremonese. I may still quote his treatise on hygiene with special reference to Egypt (fi daf mudar al-abdan bi-ard Misr). He wrote various other commentaries on Hippoctates and Galen and on Ptolemy's astrological books.

C. Brocklmann: Arabischen Litteratur (vol. 1, 484, 1898).

Arabic-Writing physicians of the East

IBN SINA

Abu Ali al-Hassan ibn Abdallah ibn Sina. Hebrew, Aven Sina; Latin, Avicenna. Born in 980 at Afshana, near Bukhara, died in Hamadhan, 1037. Encyclopaedist, philosopher, physician, mathematician, astronomer. The most famous scientist of Islam and one of the most famous of all races, places, and times; one may say that his thought represents the climax of mediaeval philosophy. He wrote a many great treatises in prose and verse; most of them in Arabic, a few in Persian. His philosophical encyclopedia (Kitab al-shifa, sanatio) implies the following classification: theoretical knowledge (subdivided, with regard to increasing abstraction, into physics, mathematics, and metaphysics), practical knowledge (ethics, economy, politics). His philosophy roughly represents the Aristotelian tradition as modified by Neoplatonic influences and Muslim theology. Among his many other philosophical works, I must still quote a treatise on logic, Kitab al-isharat wal-tanbihat (The Book of Signs and Adonitions). As ibn Sina expressed his views on almost any subject very clearly, very forcible, and generally more than once, his thought is, or at any rate can be, known with great accuracy.

His most important medical works are the Qanun (Canon) and a treatise on cardiac drugs (hitherto unpublished). The Qanun fi-l-tibb is an immense encyclopedia of medicine (of about a million words), a codification of the whole ancient and Muslim knowledge. Being similar in many respects to Galen, Ibn Sina elaborated to a degree the Galenic classifications (for example, he distinguished 15 qualities of pain). Because of its formal perfection as well as its intrinsic value, the Qanun superseded Razi's Hawi, Ali ibn Abbas's Maliki, and even works of Galen, and remained supreme for six centuries. However the very success of Ibn Sina as an encyclopedist caused his original observations to be correspondingly depreciated. Yet the Qanun contains many examples of good observation - distinction of mediastinitis from pleurisy; contagious nature of phthitis; distribution of diseases by soil and water; careful description of skin troubles, of sexual diseases; and supervisions; of nervous ailments (including love sickness); many psychological and pathological facts clearly analyzed if badly explained.

Ibn Sina's interest in mathematics was philosophical rather than technical and such as we would expect in a late Neoplatonist. He explained the casting out of nines and its application to the verification of square and cubes. Many of his writings were devoted to mathematical and astronomical subjects. He composed a translation on Euclid. He made astronomical observations, and devised a contrivance the purpose of which was similar to that of the vernier, that is, to increase the precision of instrumental readings.

He made a profound study of various physical questions - motion, contact, force, vacuum, infinity, light, and heat. He observed that if the perception of light is due to the emission of some sort of particles by the luminous source, and speed of light must be finite. He made investigations on specific gravity.

He did not believe the possibility of chemical transmutation, because in his opinion the differences of the metals were not superficial, but much deeper; coloring or bronzing the metals does not affect their essence. It should be noted that these views were radically opposed to those which were then generally accepted.

Ibn Sina's treatise on minerals was the main source of the geological ideas of the Christian encyclopedist of the thirteenth century.

Ibn Sina wrote an autobiography which was completed by his favorite disciple al-Juzajani.

His triumph was too complete; it discouraged original investigations and sterilized intellectual life. Like Aristotle and Vergil, Avicenna was considered by the people of later times as a magician.

C. Brocklmann: Geschichte der arabischen Litteratur (vol. 1, 452-458, 1898. With list of 99 works).

IBN AL-TAIYIB

Abu-l-Faraj Abdallah Ibn al-Taiyib al-Iraqi. Latin name : Abulpharagius Abdalla Benattibus. Died in 1043-44. Nestorian physician. Secertary to Elias I, Nestorian Catholics from 1028 to 1049. Physician at the Adudite hospital in Bagdad. He had many commentaries on Greek medicine, and original memories on various medical topics, also a translation of the pseudo-Aristotelian De plantis, with additional excerpts from ancient literature.

From Arabic translation of the Diatessaron ascribed to him.

Brocklmann: Arabischen Litteratur (vol. 1, 482, 1898).

ABU SA'ID UBAID ALLAH

Abu Sa'id Ubaid Allah ibn Bakhtyashu. Flourished in Maiya-fariqin, Jazirah; friend of Ibn Butlan; died in 1058. Physician. The last and possibly the greatest representative of the Bukhtyashu, a syrian family of physicians which emigrated from Junsishapur to Bagdad in 765. His main works are the Reminder of the Homestayer, dealing with the philosophical terms used in medicine, and a treatise on lovesickness.

C. Brocklmann: Encyclopaedia of Islam (t. 1, 601, 1911).

IBN BUTLAN

Abu-l-Hasan al-Mukhtar ibn al-Hasan ibn Abdun ibn Sa'dun ibn Butlan. Latin name: Elluchasem Elimither. Flourished in Bagdad; died, probably in Antioch, in or soon after 1063. Christian physician. He wrote synoptic tables of hygiene, dietetics, domestic medicine, called the Tables of Health. He probably originated that form of synopsis, which was developed by ibn Jazla (q. v., second half of eleventh century). Medical polemic with Ali ibn Ridwan.

C. Brocklmann: Arabischen Litteratur (vol. 1, 483, 1898).

ALI IBN ISA

Ali ibn Isa or Jesu Haly. flourished in Bagdad in the first half of the eleventh century. He is said to have been a christian. The most Famous Arabic oculist. His "Manual" in three books, Tadhkirat al-kahhalin, is the oldest Arabic work on ophthalmology of which the original text is completely extant. It is based partly on ancient knowledge, partly on personal experience. It is at once very detailed and very comprehensive. The first book deals with the anatomy and physiology of the eye; the second with the diseases externally visible; the third with hidden diseases, dietetics, and general medicine from the oculistic standpoint; 130 eye diseases are carefully described; 143 drugs characterized.

J. Hirschberg: Die arabischen Lehrbucher der Augenheilkunde (Abhd. der preuss. Ak. der Wiss., 117 p., Berlin, 1905).