MOHAMMAD BIN MUSA AL-KHAWARIZMI

(Died 840 C.E.)

Abu Abdullah Mohammad Ibn Musa al-Khawarizmi was born at Khawarizm (Kheva), south of Aral sea. Very little is known about his early life, except for the fact that his parents had migrated to a place south of Baghdad. The exact dates of his birth and death are also not known, but it is established that he flourished under Al- Mamun at Baghdad through 813-833 and probably died around 840 C.E.
Khawarizmi was a mathematician, astronomer and geographer. He was perhaps one of the greatest mathematicians who ever lived, as, in fact, he was the founder of several branches and basic concepts of mathematics. In the words of Phillip Hitti, he influenced mathematical thought to a greater extent than any other medieval writer. His work on algebra was outstanding, as he not only initiated the subject in a systematic form but he also developed it to the extent of giving analytical solutions of linear and quadratic equations, which established him as the founder of Algebra. The very name Algebra has been derived from his famous book Al-Jabr wa-al-Muqabilah. His arithmetic synthesised Greek and Hindu knowledge and also contained his own contribution of fundamental importance to mathematics and science. Thus, he explained the use of zero, a numeral of fundamental importance developed by the Arabs. Similarly, he developed the decimal system so that the overall system of numerals, 'algorithm' or 'algorizm' is named after him. In addition to introducting the Indian system of numerals (now generally known as Arabic numerals), he developed at length several arithmetical procedures, including operations on fractions. It was through his work that the system of numerals was first introduced to Arabs and later to Europe, through its translations in European languages. He developed in detail trigonometric tables containing the sine functions, which were probably extrapolated to tangent functions by Maslama. He also perfected the geometric representation of conic sections and developed the calculus of two errors, which practically led him to the concept of differentiation. He is also reported to have collaborated in the degree measurements ordered by Mamun al-Rashid were aimed at measuring of volume and circumference of the earth.
The development of astronomical tables by him was a significant contribution to the science of astronomy, on which he also wrote a book. The contribution of Khawarizmi to geography is also outstanding, in that not only did he revise Ptolemy's views on geography, but also corrected them in detail as well as his map of the world. His other contributions include original work related to clocks, sundials and astrolabes.
Several of his books were translated into Latin in the early 12th century. In fact, his book on arithmetic, Kitab al-Jam'a wal- Tafreeq bil Hisab al-Hindi, was lost in Arabic but survived in a Latin translation. His book on algebra, Al-Maqala fi Hisab-al Jabr wa-al- Muqabilah, was also translated into Latin in the 12th century, and it was this translation which introduced this new science to the West "completely unknown till then". He astronomical tables were also translated into European languages and, later, into Chinese. His geography captioned Kitab Surat-al-Ard, together with its maps, was also translated. In addition, he wrote a book on the Jewish calendar Istikhraj Tarikh al-Yahud, and two books on the astrolabe. He also wrote Kitab al-Tarikh and his book on sun-dials was captioned Kitab al-Rukhmat, but both of them have been lost.
The influence of Khawarizmi on the growth of science, in general, and mathematics, astronomy and geography in particular, is well established in history. Several of his books were readily translated into a number of other languages, and, in fact, constituted the university textbooks till the 16th century. His approach was systematic and logical, and not only did he bring together the then prevailing knowledge on various branches of science, particularly mathematics, but also enriched it through his original contribution. No doubt he has been held in high repute throughout the centuries since then.





THABIT IBN QURRA

(836-901 C.E.)

Thabit Ibn Qurra Ibn Marwan al-Sabi al-Harrani was born in the year 836 C.E. at Harran (present Turkey). As the name indicates he was basically a member of the Sabian sect, but the great Muslim mathematician Muhammad Ibn Musa Ibn Shakir, impressed by his knowledge of languages, and realising his potential for a scientific career, selected him to join the scientific group at Baghdad that was being patronised by the Abbasid Caliphs. There, he studied under the famous Banu Musa brothers. It was in this setting that Thabit contributed to several branches of science, notably mathematics, astronomy and mechanics, in addition to translating a large number of works from Greek to Arabic. Later, he was patronised by the Abbasid Caliph al-M'utadid. After a long career of scholarship, Thabit died at Baghdad in 901 C.E.
Thabit's major contribution lies in mathematics and astronomy. He was instrumental in extending the concept of traditional geometry to geometrical algebra and proposed several theories that led to the development of non-Euclidean geometry, spherical trigonometry, integral calculus and real numbers. He criticised a number of theorems of Euclid's elements and proposed important improvements. He applied arithmetical terminology to geometrical quantities, and studied several aspects of conic sections, notably those of parabola and ellipse. A number of his computations aimed at determining the surfaces and volumes of different types of bodies and constitute, in fact, the processes of integral calculus, as developed later.
In astronomy he was one of the early reformers of Ptolemic views. He analysed several. problems related to the movements of sun and moon and wrote treatises on sun-dials.
In the fields of mechanics and physics he may be recognised as the founder of statics. He examined conditions of equilibrium of bodies, beams and levers.
In addition to translating a large number of books himself, he founded a school of translation and supervised the translation of a further large number of books from Greek to Arabic.
Among Thabit's writings a large number have survived, while several are not extant. Most of the books are on mathematics, followed by astronomy and medicine. The books have been written in Arabic but some are in Syriac. In the Middle Ages, some of his books were translated into Latin by Gherard of Cremona. In recent centuries, a number of his books have been translated into European languages and published.
He carried further the work of the Banu Musa brothers and later his son and grandson continued in this tradition, together with the other members of the group. His original books as well as his translations accomplished in the 9th century exerted a positive influence on the development of subsequent scientific research.


ALI IBN RABBAN AL-TABARI

(838-870 C.E.)

This accomplished Hakim was the tutor of the unparalleled physician Zakariya al-Razi. Luck favoured the disciple more than the teacher in terms of celebrity. As compared to Razi people know very little about his teacher Ali.
Ali Bin Rabban's surname was Abu al-Hasan, the full name being Abu al-Hasan Ali Bin Sahl Rabban al-Tabari. Born in 838 C.E. his father Sahl hailed from a respectable Jew family. The nobility and sympathy inherent in his very nature soon endeared him to his countrymen so much so that they used to call him Rabban which implies "my leader".
Professionally Sahl was an extremely successful physician. He had command over the art of calligraphy too. Besides he had a deep insight into the disciplines of Astronomy, Philosophy, Mathematics and Literature. Some complicated articles of Batlemus's book al-Mijasti came to be resolved by way of Sahl's scholarly expertise, translators preceding him had failed to solve the mystery.
Ali received his education in the disciplines of Medical science and calligraphy from his able father Sahl and attained perfection in these fields. He had also mastered Syriac and Greek languages to a high degree of proficiency.
Ali hailed from a Israelite family. Since he had embraced Islam, he is classified amongst Muslirn Scholars. This family belonged to Tabristan's famous city Marv.
The fame acquired by Ali Bin Rabban did not simply account for the reason that a physician of the stature of Zakariya al-Razi was amongst his disciple. In fact the main cause behind his exalta- tion lies in his world-renowned treatise Firdous al-Hikmat.
Spread over seven parts, Firdous al-Hikmat is the first ever Medical encyclopaedia which incorporates all the branches of medical science in its folds. This work has been published in this century (20th century) only. Prior to this publication only five of his manuscripts were to be found scattered in libraries the world over. Dr. Mohammed Zubair Siddiqui compared and edited the manuscripts. In his preface he has provided extremely useful information regarding the book and the author and, wherever felt necessary, explanatory notes have been written to facilitate publication of this work on modern publishing standards.
Later on this unique work was published with the cooperation of English and German institutions. Following are the details of its all seven parts:
1. Part one: Kulliyat-e-Tibb. This part throws light on contempo- rary ideology of medical science. In that era these principles formed the basis of medical science.
2. Part two: Elucidation of the organs of the human body, rules for keeping good health and comprehensive account of certain muscular diseases.
3. Part three: Description of diet to be taken in conditions of health and disease.
4. Part four: All diseases right from head to toe. This part is of profound significance in the whole book and comprises twelve papers:
i) General causes relating to eruption of diseases. ii) Diseases of the head and the brain. iii) Diseases relating to the eye, nose, ear, mouth and the teeth. iv) Muscular diseases (paralysis and spasm). v) Diseases of the regions of the chest, throat and the lungs. vi) Diseases of the abdomen. vii) Diseases of the liver. viii) Diseases of gallbladder and spleen. ix) Intestinal diseases. x) Different kinds of fever. xi) Miscellaneous diseases- brief explanation of organs of the body. xii) Examination of pulse and urine. This part is the largest in the book and is almost half the size of the whole book.
5. Part five: Description of flavour, taste and colour.
6. Part six: Drugs and poison.
7. Part seven: Deals with diverse topics. Discusses climate and astronomy. Also contains a brief mention of Indian medicine.
Though he wrote Firdous al-Hikmat in Arabic but he simultaneously translated it into Syriac. He has two more compilations to his credit namely Deen-o-Doulat and Hifdh al-Sehhat. The latter is available in manuscript-form in the library of Oxford University. Besides Medical science, he was also a master of Philosophy, Mathematics and Astronomy. He breathed his last around 870 C.E.

ABU ABDULLAH AL-BATTANI

(868-929 C.E.)

Abu Abdallah Muhammad Ibn Jabir Ibn Sinan al-Battani al-Harrani was born around 858 C.E. in Harran, and according to one account, in Battan, a State of Harran. Battani was first educated by his father Jabir Ibn San'an al-Battani, who was also a well-known scientist. He then moved to Raqqa, situated on the bank of the Euphrates, where he received advanced education and later on flourished as a scholar. At the beginning of the 9th century, he migrated to Samarra, where he worked till the end of his life in 929 C.E. He was of Sabian origin, but was himself a Muslim.
Battani was a famous astronomer, mathematician and astrologer. He has been held as one of the greatest astronomists of Islam. He is responsible for a number of important discoveries in astronomy, which was the result of a long career of 42 years of research beginning at Raqqa when he was young. His well-known discovery is the remarkably accurate determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds, which is very close to the latest estimates. He found that the longitude of the sun's apogee had increased by 16° , 47' since Ptolemy. This implied the important discovery of the motion of the solar apsides and of a slow variation in the equation of time. He did not believe in the trapidation of the equinoxes, although Copernicus held it.
Al-Battani determined with remarkable accuracy the obliquity of the ecliptic, the length of the seasons and the true and mean orbit of the sun. He proved, in sharp contrast to Ptolemy, the variation of the apparent angular diameter of the sun and the possibility of annular eclipses. He rectified several orbits of the moon and the planets and propounded a new and very ingenious theory to determine the conditions of visibility of the new moon. His excellent observations of lunar and solar eclipses were used by Dunthorne in 1749 to determine the secular acceleration of motion of the moon. He also provided very neat solutions by means of orthographic projection for some problems of spherical trigonometry.
In mathematics, he was the first to replace the use of Greek chords by sines, with a clear understanding of their superiority.He also developed the concept of cotangent and furnished their table in degrees.
He wrote a number of books on astronomy and trigonometry. His most famous book was his astronomical treatise with tables, which was translated into Latin in the 12th century and flourished as De scienta stellerum — De numeris stellerum et motibus. An old translation of this is available of the Vatican. His Zij was, in fact, more accurate than all others written by that time.
His treatise on astronomy was extremely influential in Europe till the Renaissance, with translations available in several languages. His original discoveries both in astronomy and trigonometry were of great consequence in the development of these sciences.

AL-FARGHANI

(C. 860 C.E.)

Abu'l-Abbas Ahmad ibn Muhammad ibn Kathir al-Farghani, born in Farghana, Transoxiana, was one of the most distinguished astronomers in the service of al-Mamun and his successors. He wrote "Elements of Astronomy" (Kitab fi al-Harakat al-Samawiya wa Jawami Ilm al-Nujum i.e. the book on celestial motion and thorough science of the stars), which was translated into Latin in the 12th century and exerted great influence upon European astronomy before Regiomontanus. He accepted Ptolemy's theory and value of the precession, but thought that it affected not only the stars but also the planets. He determined the diameter of the earth to be 6,500 miles, and found the greatest distances and also the diameters of the planets.
Al-Farghani's activities extended to engineering. According to Ibn Tughri Birdi, he supervised the construction of the Great Nilometer at al-Fustat (old Cairo). It was completed in 861, the year in which the Caliph al-Mutawakkil, who ordered the construction, died. But engineering was not al-Farghani's forte, as transpires from the following story narrated by Ibn Abi Usaybi'a.
Al-Mutawakkil had entrusted the two sons of Musa ibn Shakir, Muhammad and Ahmad, with supervising the digging of a canal named al-Ja'fari. They delegated the work to Al-Farghani, thus deliberately ignoring a better engineer, Sind ibn Ali, whom, out of professional jealousy, they had caused to be sent to Baghdad, away from al-Mutawakkil's court in Samarra. The canal was to run through the new city, al-Ja'fariyya, which al-Mutawakkil had built near Samarra on the Tigris and named after himself. Al-Farghani committed a grave error, making the beginning of the canal deeper than the rest, so that not enough water would run through the length of the canal except when the Tigris was high. News of this angered the Caliph, and the two brothers were saved from severe punishment only by the gracious willingness of Sind ibn Ali to vouch for the correctness of al-Farghani's calculations, thus risking his own welfare and possibly his life. As had been correctly predicted by astrologers, however, al-Mutawakkil was murdered shortly before the error became apparent. The explanation given for Al-Farghani's mistake is that being a theoretician rather than a practical engineer, he never successfully completed a construction.
The Fihrist of Ibn al-Nadim, written in 987, ascribes only two works to Al-Farghani: (1) "The Book of Chapters, a summary of the Almagest" (Kitab al-Fusul, Ikhtiyar al-Majisti) and (2) "Book on the Construction of Sun-dials" (Kitab 'Amal al-Rukhamat).
The Jawami, or 'The Elements' as we shall call it, was Al- Farghani's best-known and most influential work. Abd al-Aziz al-Qabisi (d. 967) wrote a commentary on it, which is preserved in the Istanbul manuscript, Aya Sofya 4832, fols. 97v-114v. Two Latin translations followed in the 12th century. Jacob Anatoli produced a Hebrew translation of the book that served as a basis for a third Latin version, appearing in 1590, whereas Jacob Golius published a new Latin text together with the Arabic original in 1669. The influence of 'The Elements' on mediaeval Europe is clearly vindicated by the presence of innumerable Latin manuscripts in European libraries.
References to it by medieval writers are many, and there is no doubt that it was greatly responsible for spreading knowledge of Ptolemaic astronomy, at least until this role was taken over by Sacrobosco's Sphere. But even then, 'The Elements' of Al-Farghani continued to be used, and Sacrobosco's Sphere was evidently indebted to it. It was from 'The Elements' (in Gherard's translation) that Dante derived the astronomical knowledge displayed in the 'Vita nuova' and in the 'Convivio'


MOHAMMAD IBN ZAKARIYA AL-RAZI

(864-930 C.E.)

Abu Bakr Mohammad Ibn Zakariya al-Razi (864-930 C.E.) was born at Ray, Iran. Initially, he was interested in music but later on he learnt medicine, mathematics, astronomy, chemistry and philosophy from a student of Hunayn Ibn Ishaq, who was well versed in the ancient Greek, Persian and Indian systems of medicine and other subjects. He also studied under Ali Ibn Rabban. The practical experience gained at the well-known Muqtadari Hospital helped him in his chosen profession of medicine. At an early age he gained eminence as an expert in medicine and alchemy, so that patients and students flocked to him from distant parts of Asia.
He was first placed in-charge of the first Royal Hospital at Ray, from where he soon moved to a similar position in Baghdad where he remained the head of its famous Muqtadari Hospital for along time. He moved from time to time to various cities, specially between Ray and Baghdad, but finally returned to Ray, where he died around 930 C.E. His name is commemorated in the Razi Institute near Tehran.
Razi was a Hakim, an alchemist and a philosopher. In medicine, his contribution was so significant that it can only be compared to that of Ibn Sina. Some of his works in medicine e.g. Kitab al- Mansoori, Al-Hawi, Kitab al-Mulooki and Kitab al-Judari wa al- Hasabah earned everlasting fame. Kitab al-Mansoori, which was translated into Latin in the 15th century C.E., comprised ten volumes and dealt exhaustively with Greco-Arab medicine. Some of its volumes were published separately in Europe. His al-Judari wal Hasabah was the first treatise on smallpox and chicken-pox, and is largely based on Razi's original contribution: It was translated into various European languages. Through this treatise he became the first to draw clear comparisons between smallpox and chicken-pox. Al-Hawi was the largest medical encyclopaedia composed by then. It contained on each medical subject all important information that was available from Greek and Arab sources, and this was concluded by him by giving his own remarks based on his experience and views. A special feature of his medical system was that he greatly favoured cure through correct and regulated food. This was combined with his emphasis on the influence of psychological factors on health. He also tried proposed remedies first on animals in order to evaluate in their effects and side effects. He was also an expert surgeon and was the first to use opium for anaesthesia.
In addition to being a physician, he compounded medicines and, in his later years, gave himself over to experimental and theoretical sciences. It seems possible that he developed his chemistry independently of Jabir Ibn Hayyan. He has portrayed in great detail several chemical reactions and also given full descriptions of and designs for about twenty instruments used in chemical investigations. His description of chemical knowledge is in plain and plausible language. One of his books called Kitab-al-Asrar deals with the preparation of chemical materials and their utilization. Another one was translated into Latin under the name Liber Experi- mentorum, He went beyond his predecessors in dividing substances into plants, animals and minerals, thus in a way opening the way for inorganic and organic chemistry. By and large, this classification of the three kingdoms still holds. As a chemist, he was the first to produce sulfuric acid together with some other acids, and he also prepared alcohol by fermenting sweet products.
His contribution as a philosopher is also well known. The basic elements in his philosophical system are the creator, spirit, matter, space and time. He discusses their characteristics in detail and his concepts of space and time as constituting a continuum are outstanding. His philosophical views were, however, criticised by a number of other Muslim scholars of the era.
He was a prolific author, who has left monumental treatises on numerous subjects. He has more than 200 outstanding scientific contributions to his credit, out of which about half deal with medicine and 21 concern alchemy. He also wrote on physics, mathematics, astronomy and optics, but these writings could not be preserved. A number of his books, including Jami-fi-al-Tib, Mansoori, al-Hawi, Kitab al-Jadari wa al-Hasabah, al-Malooki, Maqalah fi al- Hasat fi Kuli wa al-Mathana, Kitab al-Qalb, Kitab al-Mafasil, Kitab-al- 'Ilaj al-Ghoraba, Bar al-Sa'ah, and al-Taqseem wa al-Takhsir, have been published in various European languages. About 40 of his manuscripts are still extant in the museums and libraries of Iran, Paris, Britain, Rampur, and Bankipur. His contribution has greatly influenced the development of science, in general, and medicine, in particular.

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