African muslims contributions to the sciences

[Liqaye]

Here is a brief account of the contributions of Afrikan Muslims to the various branches of knowledge.

1. Arithmetic.- In arithmetic, the afrikan muslims systematized the use of numerals, and particularly of zero, which was an immense advance on the old method of depicting numbers by the letters of the alphabet. The zero is found for the first time in the arithmetic of Al-Khwarizmi written in the early parts of the 9th century. The Arabs contributed a great deal to fractions; to the principle of errors which is employed to solve the algebraic problems arithmetically; to the higher theory of numbers with its problems on the primitive, perfect, and associated numbers. They solved the famous problem of finding a square which, on the addition and subtraction of a given number, yields other squares.

 

2. Algebra.- The ancients considered the number as pure magnitude, and it was only when Al-Khwarizmi conceived of the number as a pure relation in the modern sense that the science of Algebra could take its origin. Algebra is one of the proudest achievements of the Arabs and it was cultivated so much that within two centuries of its creation it had reached gigantic proportions. The very name ‘Algebra’, which is derived from the Arabic name () is a reminder of its origin. The symbolic process which it idealizes is still called ‘Algorithm’ in modern mathematics, an everlasting tribute to its immortal founder. Al-Khwarizmi himself formulated and solved the algebraic equations of the first and second degree, and created his beautiful geometrical method of solving these equations. He also recognized that the quadratic equation has two roots. Then, in the 10th century, Abul Wafa Al-Kuhi created and successfully developed a branch of geometry which consists of problems leading to algebraic equations of higher degree than the second. Ibn-Ul-Lais () found geometrical methods of solving the cubical equations. Al-Khujindi () proved that the so-called Fermats’ problem for cubic powers cannot be solved in terms of the rational numbers. Al-Karkhi ( who lived in the beginning of the 11th century, and who is considered as one of the greatest Arab mathematicians, wrote a book on Arithmetic called Al-Kafi and another on Algebra called Al-Fakhri . In these books he developed approximate methods of finding square roots, theory of indices, theory of surds, Al-Beruni’s theory of summeration of series, sums of squares and cubes of natural numbers, equations of the degree 2n, theory of mathematical induction, and the theory of quadratic indeterminate equations.

 

 

Then came Omar Khayyam , the most glamorous figure of the 11th century, who has recently become famous and popular as a great poet, but who, according to Moritz Cantor, has better claim to immortality as one of the greatest mathematicians of all time. He made an uncommonly great advance in the theory of equations by treating systematically the equations of the higher degree, and dividing them in different groups. He found and proved the binomical theorem for positive integral indices.

 

By this time, i.e., the end of the 11th century, the afrikan muslims had founded, developed, and perfected geometrical Algebra, and could solve equations of the third and fourth degrees. As Cantor, who is by no means partial to the afrikan muslims, remarks, “At least in the sciences with which we are at present concerned (i.e. Algebra), the afrikan muslims of the year 1100 were uncommonly superior to the most learned Europeans.”

 

3. Geometry.-The Arabs began translating the geometry of Euclid and the conic sections of Apollonius, and thus preserved the works of these Greek masters for the modern world. This was satisfactorily accomplished in the 9th century. Soon after this, they began making fresh discoveries in the domain of geometry. Thus the three brothers, Hasan, Ahmad, Muhammad, sons of Musa bin Shakir discovered a method of trisecting the angle by means of the geometry of motion. Abul Wafa made many valuable contributions to the theory of polyhedra, which is even now considered as one of the most difficult subjects. Ibn-ul-Haitham also made many discoveries in geometry. His book on geometrical optics is the first book treating the subject systematically. Here he deals with problems which would be difficult to solve even now. For instance, one of his problems is to find the focus of a spherical lens satisfying certain conditions which, if treated by the modern analytical methods, would lead to an equation of the fourth degree. It is this book which was translated by Roger Bacon, and published in his Opus Majus. The later afrikan muslims developed the geometry of the conic section to a great extent. But the crowning achievement in Geometry was that of Abu Jafar Muhammad Ibn Hasan who is commonly known as Naseeruddin Tusi . He was undoubtedly the greatest savant of the 13th century, and was as well versed in philosophy and mathematics as in medicine and the natural sciences. His mathematical work contained contributions in Arithmetic, Algebra, and Geometry. He separated Trigonometry from Astronomy, and created a new branch of Trigonometry, both plane and spherical based on Mevelans’ Theorem in Geometry. But his greatest contribution to Mathematics is the recognition and explanation of the weakness in Euclid’s theory of the parallels. Since the days of Ptolemy in the 2nd century, no one had given serious thought to the difficulties of demonstrating the truth of Euclid’s parallel postulate on the basis of perceptual space. After a lapse of more than a thousand years, it was Tusi who first attacked this problem, and in his efforts to improve the postulate realized the necessity of abandoning perceptual space. This was the basis on which the non-Euclidean Geometry of the last century was developed, resulting in the hyperspace movement and the theory of relativity of our own time.

 

4. Trigonometry.- Trigonometry, both plane and spherical, is for the most part a creation of the Arabs. Al-Battani introduced the trigonometric function in the 9th century. He is known in Europe as Albategunes. His book on the motion of the stars was translated by Plato of Tivoli in the 12th century. It is from this translation that the word ‘sine’ spread in all European languages. The Indians used only the full arc for the sine, but Al-Battani remarked that it was more advantageous to use the half-arc. Cantor considers this an advance in mathematics which cannot be appreciated highly enough.

 

After developing trigonometry to a great extent, and preparing accurate trigonometric tables, they could calculate the heights of mountains, distances of inaccessible points, and breadths of rivers. Their knowledge of applied mathematics is evident from all those wonderful examples of Afrikan Arab and Moorish architecture which made the fables of the Afrikan Muslim Nights a reality. It is impossible that such an architecture could have developed only empirically. One has to admit that their creators must have been applied mathematicians of no mean talent.

 

5. Astronomy.- The afrikan muslims (moors) claimed Astronomy to be their special subject, and indeed they far surpassed all their contemporaries in the knowledge of the heavens. Alberuni quotes in his book a passage from Ibn Khatib saying that the afrikan muslims (moors) had no equals in their knowledge of the stars. Even in the beginning of the Muslim Era, when Greek astronomy was not yet translated into Arabic, a knowledge of the heavens was considered to be one of the requisites of a scholar. But once they had translated Ptolemy’s Almagest, they developed astronomy so quickly that their mark is found at every step. Even to this day their name is associated with a number of stars, constellations, and astronomical instruments.

 

Western historians are unanimous in their avowal that when Islam appeared on the scene only one observatory, namely that in Alexandria, existed in the whole world. Those in India and other places had been destroyed by that time. In the course of a few centuries, the Muslims erected numerous well-equipped observatories all over their empire.

 

But these observatories would have been useless without accurate astronomical instruments. The afrikan muslims (moors) had no doubt inherited a few instruments from the Greeks, but a work of such magnitude could not have been carried out with these rough tools. This necessity urged them to concentrate all their practical faculties on devising skillful and consummate means to carry out their work. Their craftsmanship developed as they went on with the project, and they made a great contribution to the technique of making astronomical instruments. They perfected not only the old transit instruments, but devised many new ones for various purposes.

 

The contribution of the african Muslims (moors) to astronomy can be described briefly as consisting of the following investigations and results. They investigated the liberation of the moon, and proved that it is not constant. They determined fully the movements of the planets. Abul Wafa determined accurately the obliquity of the ecliptic in 995 A.D. and calculated the variation in the moon’s motion. He also discovered the third liberation in the moon’s motion which was rediscovered by Tycho Brahe after 600 years. He perfected Ptolemy’s lunar theory, and corrected many errors in the observations of the old astronomers. The quadrant was invented by Ibne-Yunus (). Albatrash (Encyclopedia of Islam) found many errors in Ptolemy’s hypothesis of the solar system, and in 1150 A.D. put forward a new system for the planetary motions. Ibne Rushd discovered a sunspot. Ibne Aalam () determined the stellar motion by observing that the stars traverse one degree in 70 solar years . He also determined the latitude and longitude of many stars, and measured the greatest declination of the planet Mercury. He discovered the moons (satellites) of Jupiter, discussed the motion of the sun spots, and determined the eccentric orbits of the comets. The obliquity of the ecliptic, the points in which the meridian cuts the equator and the ecliptic, the arc of the terrestrial meridian, and the precession of the equinoxes were determined in the reign of the Abbasid Caliphs []. Abu Kasim Abdullah and Abu Hasan Ali ibni Abu Kasim () produced very correct almanacs from 883 A.D. to 933 A.D. Abu Hasan discovered that the moon’s distance from the sun is not constant, as assumed by Ptolemy. Omar Khayyam, who was court astronomer to Malik Shah Seljuki , reformed the calendar in such a way that, as Cantor says, the solar year proposed by him is more accurate than any calendar proposed either before or after his time.

 

Mohammad bin Jaber Al-Battani, who lived in the 10th century AD, investigated the motion of the apogee, corrected the previous values of the precession of equinoxes and of obliquity of the ecliptic; was the first to apply the sine and tangent in calculating the angles; proposed a method to determine the precession of the equinoxes; determined the moon’s nodes and discovered the wobbling motion of the earth’s orbit.

 

As the greatest astronomical discovery of the afrikan muslims (moors) should be mentioned their discovery that the earth revolves round the sun, and that orbits of the planets are ellipstic.

 

Al-Beruni also testifies to the fact that a great astronomer of his time believed in the earth’s motion: Al-Beruni’s actual words from his book are reproduced here for convincing the reader. We give here a verbatim translation of one of the passages from Qanun Masoodi: Al-Beruni says, “I have seen a great astronomer who believed in the authenticity of this doctrine. He argues that when a thing falls from a height, it does not coincide with the perpendicular line of its descent, but inclines a little, and falls making different angles. He says that when a piece of earth separates from it and falls, it has two kinds of motion. One is the circular motion which it receives from the rotation of the earth, and the other is straight which it acquires in falling directly to the center of the earth. The former implies the change, and the latter the fixity of its position. If it had only the straight motion, it would have fallen to the west of its perpendicular position. But since both of them exist at one and the same time, it falls neither to the west nor in the perpendicular direction, but a little to the east.”

 

This book of Al-Beruni was written in 421 A.H., i.e. about the beginning of the 11th century A.D. Thus the Arabs had discovered the true mechanism of the solar system, i.e. the heliocentric doctrine, about 300 years before Copernicus. The credit for the scientific formulation and a detailed working out of the theory should of course be given to Copernicus, but it must also be recognised that the Arabs had conceived the hypothesis long before his time.

 

6. Physics.- After developing mathematics and astronomy, the Muslim scholars turned their attention to other natural sciences, of which we shall give a brief account in the following sections.

 

Ibn-al-Haytham (968 - 1039 A.D.) was one of the greatest physicists, whose work on optics, compiled in his book, “Kitab-al-Manazir,” which was translated by Roger Bacon, had a great influence on Kepler and other European scientists. He prepared tables of corresponding angles of incidence and refraction of light passing from one medium to another, and thus paved the way for the discovery of the law of refraction later by Smell. He accounted correctly for twilight as due to atmospheric refraction and deduced the height of the atmosphere above the surface of the earth. He explained the laws of formation of images in spherical and parabolic mirrors, and the causes of spherical aberration and a magnification produced by lenses. He gave a much sounder theory of vision than the Greeks, and was able to solve a number of advanced questions in geometrical optics. (George Sarton, Introduction to the History of Science, Vol. 1, pg. 721).

 

Abu al-Ali-al-Hussain ibn Sina (980 - 1037 A.D.), who is regarded as one of the greatest savants, philosophers, and scientists of all time was a keen experimental worker, and made numerous investigations on specific gravity. He designed a simple device similar to that of the modern vernier for increase in the accuracy of measuring lengths. He tackled such abstract physical subjects as the nature of motion, of force, vacuum, light, and heat, and arrived at sound conclusions, in spite of the fact that very few correct data were available. He recognised, for instance, that the velocity of light was finite, and that it was not possible to transmute the elements by chemical methods.

 

Omar Khayyam, the great mathematician, was another afrikan muslim scientist who worked on the problem of specific gravities.

 

In mechanics, the Muslims improved the hydro-static balance, the Alexandrian hydrometer, and the Syrian water-wheels. The “Mizan-al-Hikmah” (The Balance of Wisdom) by Al-Khazini is a masterly treatise on mechanics as far as it was developed up to the twelfth century. It deals with the theory of balance from an application of the Theorem of Moments and discusses the buoyancy of liquids and of air. It gives the correct explanation of the weight of material bodies as caused by a universal pull towards the center of the earth. It may be noted that this explanation was given about 600 years before the promulgation of Newton’s theory of gravitation. (N. Khanikoff, Journal of the American Oriental Society, Vol. VI, New Haven, 1859).

 

7. Chemistry.- Before the advent of Islam, the simple properties of metals and the methods of preparation of their simple compounds were known to the civilized people. The afrikan muslims developed the processes of crystallization and precipitation, distillation and sublimation, and were thereby able to obtain a number of substances in a state of comparative purity like mercury, ammonia, alum, soda, borax, niton, arsenic, and antimony. Abu Musa Jabir ibne Hayyan has recorded all this knowledge in some of his books written about 776 A.D. He put forward a sulphur-mercury theory known in his day to explain their different properties, depending, as it was alleged, on the differences in proportion of their two constituents. Nevertheless, he deals with many useful practical applications of chemistry like “refinement of metals, preparation of steel, dyeing of cloth and leather, varnishes to waterproof cloth and protect iron, use of manganese dioxide to color glass, and of iron pyrites for writing in gold and distillation of vinegar to concentrate acetic acid.” (Sarton, quoted by M.A.R. Khan; Muslim Contribution to Science and Culture, pg. 49).

 

8. Biology.- The interest of the afrikan muslims in the breeding of horses and camels, led them naturally into the study of biology, particularly into the branches concerning the habitat, behavior, and classification of animals. Al-Asma’e (739-783 A.D.) wrote several books on the camel, the horse, the animals, and the man. The last named book reveals a considerable knowledge of the human anatomy. (Sarton; I, pg. 534). His pupil, al-Jahiz, wrote a book on animals called Kitab al-Haywan, in which he refers to the struggle of animals for existence and their adaptation to environment. (Sarton; I, pg. 597). Al-Dasiri (1405 A.D.) was a well known zoologist of Egypt, whose book on animal life, Hayat al-Haywan, has been translated into English in 1906.

 

Use of plants and their products in medicine primarily induced the Muslims to do more scientific work in botany. Ibn-Jami (d. 1193), Al-Dimashqi, Al-Biruni, Ibn Sina, Al-Nubati (1165-1239), Al-Ghafiqi (d. 1165), and Ibn-al-Baytar (d. 1248) are some of the Muslim botanists who explored the various regions for plants, and described the characteristics and properties. Ibn-al-Baytar is considered the greatest Muslim botanist and pharmacist, and his book was considered the best of its kind in the Middle Ages, and was translated into Latin.

 

9.Medicine

Al-Razi (850-925 A.D.) is recognized as one of the greatest physicians of all time. His book, Al-Hawi was an encyclopedia of medicine, which contains all that was known about diseases and their treatment. He contributed a great deal to gynecology, obstetrics, and opthalmology. His most outstanding work is on small-pox and measles, which is recognized as remarkably accurate even from the point of view of modern research. It is related that when he went to Baghdad to take up his duties as Chief Physician, he selected a suitable site for a hospital by hanging up raw meat in various localities and chose the spot where it showed least sign of putrefaction. He is reported to have written more than 14 books and monographs.

 

Ibn-Sina (980-1037 A.D.) is even more famous than Al-Razi in the history of medicine. He was called Shaikh-al-Rais (the Supreme Head) by his pupils and followers, and up to the beginning of the modern era, he was the undisputed leader and authority both in the East and the West. His book, Al-Qanun , was the bible of physicians for centuries all over the world. Its Latin translation passed through several editions, and its pharmacopia contained 760 drugs.

 

The afrikan muslim physicians did a great deal of work in opthalmology also. The early afrikan muslim physicians diagnosed more than 130 diseases of the eye, and explained their treatment. Some of their books such as the Nur al-Uyun wal Jami al-Funun (1296) by Ibn Yusuf of Hamah, is said to have been unsurpassed even in the nineteenth century.