The whole ninth century was essentially
a Muslim century. This more clear in the second half than of the first,
since all the scientific leaders were Muslims, or at any rate were working
with and for Muslims and wrote in Arabic.
Abbasid Caliph Al-Mutawakkil
(847-861) continued to protect men of science, chiefly the physicians,
and he encouraged the school of translators headed by Hunain ibn Ishaq.
Da ud al-Zahiri founded a new
school of theology, based upon a more literal interpretation of the Qur'an;
however, did not survive very long. Muslim published a new collection of
traditions, arranged according to legal topics, like Bukhari's, but more
The Egyptian Dhul-Nun is generally
considered the founder of Sufism, that is, of Muslim mysticism.
Arabic Mathematics and
G. Sarton clarify that when he said "Arabic" instead "Muslim"
he means that some of the most important work accomplished under Muslim
tutelage was actually done by non-Muslims but in Arabic language.
There were so many mathematical and astronomers in Islam that is
necessary to divide them into four groups as he did before: geometers;
arithmeticians; astronomers and trigometricians; astrologers.
Geometers: Al-Mahani wrote commentaries
on Euclid and Archimedes, and tried to vain and divide a sphere into two
segments, being in a given ratio. Archimedian problem became a classical
Muslim problem; it led to a cubic equation which was called al-Mahani's
equation. Hilal al-Himsi translated the first four books of Apolloinos
into Arabic. Ahmed ibn Yusuf wrote a book on proportions which are
of special importance, because through it Western mathematicians became
acquainted with the theorem of Menelaos. Al-Nairizi wrote commentaries
on Ptolemy and Euclid. Thabit ibn Qurra made very remarkable measurements
of parabolas and paraboids, but is best known as the leader of a school
of translators which produced Arabic versions of some of the mathematical
classics: Euclid, Archimedes, Apollonios, Theodosios, Ptolemy, Thabit himself
was the foremost translator and revised some of the translations made by
others. The two most important translators of his school, outside of himself,
were Yusuf al-Khuri and Ishaq ibn Hunain. A comparison of this brief account
with the similar section in the previous chapter will show that much progress
had already been made in geometry since the beginning of the century.
Arithmeticians: I mentioned in
the previous chapter the writings of al-Kindi and al-Khwarizmi were in
probability the main channels through which the Hindu numerals known in
Islam and later in the West. The earliest Muslim documents bearing such
numerals date from 874 and 888. The propagation of these numerals may have
been accelerated by the fact that the Muslim trade was exceedingly active
in those very days and reached every part of the world.
Thabit ibn Qurra developed the theory of amicable numbers. Qusta
ibn Luqa translated Diophantos.
Astronomers and Trigonometricians: Al-Mahani
made a series of astronomical observations from 855 to 866. Al-Nairizi
compiled astronomical tables and wrote an elaborate treatise on the spherical
astrolabe; he made systemic use of the tangent. Hamid ibn Ali became famous
as a constructor of astrolabes. Thabit ibn Qurra published solar observations;
he tried to improve the Ptolematic theory in planetary motions by the addition
of a ninth sphere to account for the (imaginary) trepidation of the equinoxes.
Qusta ibn Luqa wrote a treatise on the spherical astrolabes. Jabir ibn
Sinan, of whom we know nothing, but who may have been al-Battani's father,
constructed astronomical instruments, notably a spherical astrolabe.
The greatest astronomer of the age and one
of the greatest of Islam was al-Battani (Albategnius). He made a number
of observations from 877, on, compiled a catalogue of stars for the year
880, determined various astronomical coefficients with great accuracy,
discovered the motion of the solar apsides, and made an elaborate astronomical
treatise which remained authoritative until the Sixteen Century. That treatise
included naturally a trigonometical summary wherein not only sines, but
tangents and cotangents, are regularly used. It contains a table of contangents
by degrees and theorem equivalent to our formula giving the cosine of a
side of a spherical triangle in function of the cosine of the opposite
angle and of the sines and cosines of the other side.
most famous astrologers were Abu Bakr (Albubather), Ahmed ibn Yusuf,
and Ibn Qutaiba.
The whole mathematical and astronomical work
was far more original than in the first half of the century and on a relatively
high level. It is true, Thabit ibn Qurra introduced an unfortunate error
of which a great many later astronomers (including Copernicus!) remained
prisoners, but original research always implies the possibility of error.
Thabit's error was no discreditable. The elaboration of trigonometry was
continued with great skill and originality. Much attention was paid to
astronomical instruments and especially to a new one, the spherical astrolabe,
al-Battani's masterly work was a fitting climax to this wonderful activity.
So much for Islam. What was being done at
the same time at the rest of the World? Nothing.
Muslim Alchemy and Physics
Al-Jahiz seems to have some chemical knowledge,
for instance, he knew how to obtain ammonia from animal offals by dry distillation,
but it would be absurd to call him a chemist. On the other hand, the great
physician Al-Rhazi was undoubtedly a genuine chemist: he wrote various
chemical treatises, described a number of chemical instruments, attempted
to classify mineral substances, and even tried to apply his chemical knowledge
to medical purposes. He may be considered a distant ancestor of the iatrochemists
of the Sixteenth Century. He was also a physicist; he used the hydrostatic
balance to make investigations on specific gravity. The mathematician al-Nairizi
wrote a treatise on atmospheric phenomena.
The Muslims had little interest in natural history; they were certainly
not tempted to study it for its own sake, but many of their current views
on biological subjects may be found in their literary and historical compilations.
The most remarkable example is "The Book of Plants" composed by the historian
al-Dinawari. The purpose of that book was primarily philological, but contains
much valuable information for the historian of botany. Al-Jahiz's "Book
of Animals" is also a mine of information though most of it is folkloric
rather than zoological.
So much medical work was accomplished in Islam that is expedient to
divide the physicians into two groups: those who were primarily practitioners
and those who were primarily scholars and those who were engaged in translating
the Greek medical classics into Syriac and Arabic. Of course, those of
the second group were, all of them were for foreigners, non Muslims,; but
even in the first group, one-half of the physicians was christians. thus
the activity was christian rather than Muslim, but we must not forget that
by far the greatest of all of them, al-Razi, was a Muslim.
The Persian al-Razi was simply the greatest clinician of Islam and
of the whole middle ages; he was also, as we have seen, a chemist and physicist.
It would be difficult to choose between him and his contemporary al-Battani:
both were very great scientist who would have been conspicuous in any age.
I decide to call this period "The Time of al-Razi" because the physician
is known to the larger public than the astronomer, and also because his
influence can be traced more directly throughout many centuries of human
effort, East and West. I have already remarked that al-Razi might be considered
to be one of the forerunners of the iatrochemists of the Renaissance. He
wrote an immense medical encyclopaedia called Al-hawi ("Continens") and
a monograph on measles and smallpox which is the masterpiece of Muslim
medicine. Ya'qub ibn akhi Hizam was the author of a treatise on horsemanship,
which contains some rudiments of veterinary art, the earliest work of its
kind in Arabic.
The greatest of the translators was Hunain ibn Ishaq (Joannitius).
He collected great medical manuscripts, translated many of them, supervised
the activities of other scholars, and revised their translations. His role
as regard to medical literature was very similar to that of Thabit ibn
Qurra with regard to the mathematical and astronomical texts. The school
of nestorian translators beaded by Hunain must have been quite considerable,
for between them they managed to translate the greatest part of the Hippocratic
and Galenic writings into Syriac and into Arabic. Hunain wrote also original
works, notably a treatise on ophthalmology and the introduction to Galen's
Ars parva which was immensely medical writings: Hunain's son Ishaq, Hubaish
ibn al-Hassan, Isa ibn Yahia, Stephen son of Basil, Musa ibn Khalid, Thabit
ibn Qurra, Yusuf al-Khuri. Hunain was a very great man, but he was more
of a scholar than a scientist proper and his activity, which already had
begun in the middle of the previous period, ended in the middle of this
one; in other words al-Razi and al-Battani were one generation ahead of
him. The time of Hunain, extending from 826 to 877, falls just between
that of al-Khawarizimi and that of al-Razi.
Abu Abdallah Mohammed
ibn Isa al-Mahani, that is, from Mahana, Kirman, Persia. Flourished c.
860, died c. 874 to 884. Mathematician, astronomer. A series of observations
of lunar and solar eclipses and planetary conjunctions, made by him from
853 to 866, was used by Ibn Yunus. He wrote commentaries on Euclid and
Archimedes, and improved Ishaq ibn Hunain's translation of Menelaos's spherics.
He tried vainly to solve an Archimedian problem: to divide a sphere by
means of a plane into two segments being in a given ratio. That problem
led to a cubic equation, x3 + c2b
= cx2, which Muslim writers
called al-Mahani's equation.
H. Suter: Die Mathematiker
und Astronomen der Araber (26, 1900. His failure to solve the Archimedian
problem is quoted by 'Omar al-Khayyami'). See Fr. Woepcke: L'algebra d'Omar
Alkhayyami (2, 96 sq., Paris, 1851).
AHMED IBN YUSUF
Abu Ja'far Ahmed ibn
Yusuf ibn Ibrahim al-Daya al Misri, i.e., the Egyptian. Flourished
in Egypt in the second half and died about the Third Century H., c. 912.
Mathematician. Secretary of the Tulunids, who ruled in Egypt from 868 to
905. He wrote a book on similar arcs (De Similibus arcubus), commentary
on Ptolemy's Centiloquium, and a book on proportions ("De proportione et
Proportionalitate"). The latter book is important because it influenced
mediaeval thought through Leonardo de Pisa and Jordanus Nemorarius (theorem
of Menelaos about the triangle cut by a transversal; al-qatta, sector;
hence figura cata, regula catta). M. Cantor: Ahmed und sein
Buch Uber die Proportionen (Bibliotheca Mathematica, 7-9, 1888).
Latin name: Anaritius.
Abu-l-Abbas al-Fadl ibn Hatim al-Nairizi (i.e., from Nairiz, near Shiraz).
Flourished under al-Mu'tadid, Caliph from 892 to 902, died c. 922. Astronomer,
Mathematician. He compiled astronomical tables and wrote for al-Mu'tadid
a book on atmospheric phenomena, He wrote commentaries on Ptolemy and Euclid.
The latter were translated by Gherardo da Cermona. Al-Nairizi used the
so-called umbra (versa), the equivalent to the tangent, as a genuine trigonometric
line (but he was anticipated in this by Habash, q. v., first half of ninth
century). He wrote a treatise on he spherical astrolabe, which is very
elaborate and seems to be the best Arabic work on the subject. It is divided
into four books: (1) Historical and critical introduction; (2) Description
of the spherical astrolabe; its superiority over plane astrolabes and all
other astronomical instruments; (3 and 4) Applications. H. Suter: Die Mathematiker
und Astronomen der Araber (45, 1900); Nachtrage (164, 1902).
THABIT IBN QURRA
Abu Hassan Thabit
ibn Qurra Marawan al-Harrani, that is, from Harran, Mesopotamia, born 826-27
(or 835-36), flourished in Bagdad, died in 901. Harranian physician, astronomer,
mathematician. one of the greatest translators from Greek and Syriac into
Arabic; the founder of a school of translators, in which many of his own
family we remembers. apollonios (Books 5 to 7), Archimedes, Euclid, Theodosios,
Ptolemy (geography), Galen, Eutocios were translated by him or under his
direction, or translations made by others (e.g., Ishaq ibn Hunain) were
revised by him. He published solar observations, explaining his methods.
to the eight Ptolemaic spheres he added a ninth one (primum mobile) to
account for the imaginary trepidation of the equinoxes (he is chiefly responsible
for the introduction of this erroneous theory). His mensurations of parabolas
and paraboloids are very remarkable. He improved the theory of amicable
numbers (if p = 3.2n - 1; q = 3.2n-1-1;
r = 9.22n-1-1; and if
and r are prime together, 2npq
are amicable numbers). Many mathematical, astronomical, also anatomical
and medical, writings are ascribed to him (most of them in Arabic, some
in Syriac). Fihrist (272, and comment.
by index). F. Wustenfled: Geschichte der arabischen Aerzte (34-36, 1840.
Followed by notices on other members of the same family).
Joseph the Priest.
Also called Yusuf al-Qass (same meaning) or al-Sahir (the vigilant). He
was still living under the caliphate of al-Muqtafi (902 to 908). Physician
and mathematician. Translator from Syriac into Arabic. He translated Archimedes's
lost work on the triangles and Galen's "De simlicium temperamentis et facultatibus."
That the first translation was revised by Sinan ibn Thabit ibn Qurra (q.
v., first half of first century), the second by Ishaq. H. Suter: Die Mathematiker
der Araber (52, 224, 1900). Max Meyerhof: NewLight on Hunain ibn Ishaq
(Isis, VIII, 704, 1926).
HAMID IBN ALI
Abu-l-Rabi Hamid ibn
Ali al-Wasiti. From Waist in Lower Mesopotamia. Flourished in the ninth
century, probably toward the end. Muslim astronomer. According to Ibn Yunus,
Ali ibn Isa and Hamid were the foremost constructors of astrolabes. Ibn
Yunus compares them to Ptolemy and Galen! This proves the importance which
Muslims attached to good instruments. H. Suter: Mathematiker (40,
MUSLIM (OR ARABIC) MEDICINE
SABUR IBN SAHL
Flourished at Jundishapur.
Died Dec. 3, 860. Christian physician. He wrote an antidotary (Aqrabadhin),
divided into 22 books, which was possibly the earliest of its kind to influence
Muslim medicine, and other medical works. This antidotary enjoyed much
popularity until it was superseded Ibn al-Tilmidh's new one (q. v., first
half of twelfth century). F. Wustenfled:
arabische Aerzte (25, 1840).
YAHYA IBN SARAFYUN
Separion the elder.
Yahya ibn Sarafyun. Flourished in Damascus in the second half of the ninth
century. Christian physician who wrote in Syriac two medical compilations
(Kunnash, pandects), one in 12 books, the other in 7 books. the latter
was translated into Arabic by various writers and into Latin by Gherardo
da Cermona (Practica sive breviarium). It was very popular during the middle
ages. Its last book deals with antidotes. Ibn Srarfyun attached great importance
to venesection and gave subtle prescriptions concerning the choice of the
veins to be opened. Fihrist (29; 303,1. 3; and
comm. 296, note 1). Wustenfeld: Geschichte der arabischen Aerzte (49, 1840).
In Latin: Rhazes.
Abu Bakr Mohammed ibn Zakaria al Razi. Born in Ray, near Tehran, Persia,
about the middle of the ninth century. Flourished in Ray and in Bagdad.
died 923-24. Physician, physicist, alchemist. The greatest clinician of
Islam and middle ages. Galenic in theory, he combined with his immense
learning true Hippocratic wisdom. His chemical knowledge was applied by
him to medicine; he might be considered an ancestor of the iatrochemists.
Of his many writings, the most important are the "Kitab al Hawi" (Continens),
an enormous encyclopaedia containing many extracts from Greek and Hindu
authors and also observations of his own; the "Kitab al Mansuri" (Liber
Almansoris), a smaller compilation in ten books based largely on Greek
science, and finally his famous monograph on smallpox and measles "Kitab
al-jadari wal-hasba" (De variolis et morbiliis; de peste, de pestilentia),
the oldest description of variola and the masterpiece of Muslim medicine.
many contributions to gynaecology, obstetrics, and ophthalmic surgery can
be traced back to him.
He made investigations on specific gravity by means of the hydrostatic
balance, which he called al-mizan al-tabi'i. Various chemical treatises
are ascribed to him, and one of them (Arcandorum liber, apocryphal?) contains
a list of 25 pieces of chemical apparatus. He also made an attempt to classify
chemical substracts. The al-Hawi has not been published,
and there is not even a single complete manuscript in existence. A latin
translation, Liber dictus Elhavi, appeared in Brescia (1486), followed
by various Ventian editions. The liber ad Almansurem, in ten books was
first published in Milano (1481) and was frequently republished.
HUNAIN IBN ISHAQ
In Latin, Joannitius.
Abu Zaid Hunain ibn Ishaq al-Ibadi. Born in Hira, 809-10. Flourished at
Jundishapur, then in Bagdad, where he died in October 877. Famous Nestorian
physician; one of the greatest scholars and of the noblest men of his tome.
Pupil of Ibn Masawiah. Employed by the Banu Musa to collect Greek manuscripts
and translate them into arabic, he became the foremost translator of medical
works. These translations were made partly with the assistance of other
It is reported that the Abbasid caliph al-Mutawakkil created (or
endowed) a school where translations were made under Hunain's supervision.
It is not too much to say that the translations made by Hunain and his
disciplines marked a considerable progress in the history of scholarship.
He took infinite pains to obtain manuscripts of the Greek medical texts;
he collated them, examined the existing Syriac and Arabic versions, and
translated them as accurately and as well as possible. His methods remind
one of modern methods. to appreciate more the value of his efforts, one
must realize that the Syriac versions were very unsatisfactory and the
Arabic versions already available were hardly better. Hunain carefully
compared these versions with the great text to prepare his new arabic translations.
His activity was prodigious; it began as early as c.826 and lasted till
the end of his days. It is typical of his scientific honesty that he very
severely criticized the translations made by himself early in life. As
his experience increased, his scientific ideal became more exacting. He
translated a great many of Galen's works, also various writings of Hippocrates,
Plato, Aristotle, Dioscordies, and Ptolemy's Quadripartitum. The importance
of his activity can be measured in another way by stating that the translations
prepared by Hunain and his school were the foundation of that Muslim canon
of Knowledge which dominated medical thought almost to modern times.
Various medical and astronomical writings are ascribed to him (e.
g., on the tides, on meteors, on the rainbow). His most Important work
is his introduction to Galen's "Ars prava" ("Isagoge Johannitii ad Tegni
Galeni") which was mensly popular during the Middle Ages and played the
same part in the teaching of medicine as Porphyry's "Isagoge" in that of
logic. Galenic classification extended and elaborated. Fihrist (294 f and by index).
Ferdinand Wustenfeld: Geschichte der arabischen Aerzte und Naturforscher.
QUSTA IBN LUQA
Qusta ibn Luqa al-Ba'labakki,
i. e. from Baalbek or Heliopolis, Syria. Flourished in Bagdad, died in
Armenia about the end of the third century H., i. e., c. 912. A Christian
of Greek origin. Philosopher, Physician, mathematician, astronomer, Translations
of Diophantos, Theodosios, Autolycos, Hypsicles, Aristarchos, Heron were
made or revised by him, or made under his direction, He wrote commentaries
on Euclid and a treatise on the spherical astrolabe. Fihrist (295 and by index).
C. Brockelmann : Geschichte der arabischen Litteratur (Vol. I, 204-205,
JABIR IBN SINAN
Jaber ibn Sinan al-Harrani
is one of the makers of astronomical instruments mentioned in the Fihrist
at the end of the mathematical section. Nothing else is said of him, but
al-Battani's full name suggests that this Jaber may have been his father.
According to al-Biruni, this Jaber was the first to make a spherical astrolabe. Fihrist (p. 284). Sutre's
translation (p. 41). H. Suter : Die Mathematiker (68, 224, 1900).
In Latin: Albategnius,
Albatenius. The origin of that nisba is unknown. Abu Abdallah Mohammed
ibn Jabir ibn Sinan al-Battani, al-Harrani, al-Sabi, born before 858 in
or near Harran. Flourished at al-Raqqa, in the Euphrates, died in 929 near
Samarra. Of Sabin origin, though himself a Muslim. The greatest astronomer
of his race and time and one of the greatest of Islam. Various astrological
writings, including a commentary on Ptolemy's "Tetrabiblon" are ascribed
to him, but his main work is an astronomical treatise with tables ("De
scientia stellarum," " De numeris stellarum et motibus") which was extremely
influential until the Renaissance. He made astronomical observations of
remarkable range and accuracy from 877 on. His tables contain a catalogue
of fixed stars for the years 880-81 (not 911-12). He found that the longitude
of the sun's apogee had increased by 16o47` increase
since Ptolemy, that implied the discovery the motion of the solar apsides
and of a slow variation in the equation of time. He determined many astronomical
coefficients with great accuracy: precession 54.5`` a year; inclination
of the ecliptic, 23o35`. He did not believe in the trepidation
of the equinoxes. (Copernicus believed in it!)
The third chapter of his astronomy is devoted to trigonometry. He
used sines regularly with a clear consciousness of their superiority over
the Greek chords. He completed the introduction of the functions umbra
extensa and umbera versa (hence our contangents and tangents) and gave
a table of contangents be degrees. He knew the relation between the sides
and angles of a spherical triangle which we express by the formula
cos a = cos c cos c + sin b sin c cos A. H. Suter : Die Mathematiker
und Astronomen der Araber (45-47, 1900).
In Latin: Albubather.
Abu Bakr al-Hassan ibn al-Khasib. Of Persian origin. Flourished probably
in the third quarter of the ninth century. astrologer who wrote in Persian
and arabic and would hardly deserve to be quoted but for the importance
given to him in the middle ages. The work he is best known by ("De nativitatibus")
was translated into Latin by one canonicus Salio in Padua 1218; it was
also translated into Hebrew. Fihrist (p. 276 and Commentary,
p. 131). H. Suter : Die Mathematiker und Astronomen der Araber (32, 1900);
Nachtrage (162, 1902); encycl. of Islam, II, 274, 1916.