Al-Biruni

Abu'l- Rayhan Muhammad Ibn Ahmad Al-Biruni (973-1050 CE) was a scholar in the fields of mathematics, history, and medicine.[1] In fact, his interest extended to nearly all the sciences.[2] His production exceeds 146 titles in more than twenty different disciplines, such as mathematics, mathematical geography, chronology, mechanics, pharmacology, mineralogy, history, literature, religion, and philosophy. He composed an encyclopaedia of astronomy, a treatise on geography, and an epitome of astronomy.[3] But the bulk of his work lies in mathematics and related disciplines (ninety-six titles).[4] He contributed to geometry the solution of theorems that thereafter bore his name.[5] He wrote histories of Mahmud's reign, of Subukrigin, and of Khwarizm. He explained the workings of natural springs and artesian wells by the hydrostatic principle of communicating vessels.[6] Only twenty-two works of his have survived the ravages of time and only thirteen of these works have been published. His work on the demarcation of the coordinates of cities (Tahdid) was written so as to determine the direction to Makkah; Al-Biruni could determine the local meridian and the coordinates of any locality.[7]

In astronomy, Al-Biruni wrote treatises on the astrolabe, the planisphere, the armillary sphere; and formulated astronomical tables for Sultan Masud. Indeed, Al-Biruni's astronomical findings are well elaborated in his al-Qanun al-Mas'udi, a work which is a most extensive astronomical encyclopaedia, slightly short of 1,500 pages, in which he determines the motion of the solar apogee, corrects Ptolemy's findings and is able to state for the first time that the motion is not identical to
that of precession, but comes very close to it.[8]

Al-Biruni employed mathematical techniques unknown to his predecessors that involved analysis of instantaneous motion and acceleration, described in terminology that can best be understood if we assume that he had "mathematical functions" in mind.[9] In the eighth maqalah of the Qanun, al-Biruni presented a masterly exposition of both the solar as well as the lunar eclipses, specially the section dealing with al-kusufin (the images of the eclipses) which pass on the faces of the sun and the moon without affecting their body; he referred in his letter to a book on the two united and equal axes.[10] Six hundred years before Galileo, Al-Biruni discussed the theory of the earth rotating about is own axis. The following in relation to this subject is worthy of record as an indication of Al-Biruni's independence of mind:

He took it for granted that the earth is round, and noted "the attraction of all things towards the centre of the earth," and remarked that astronomic data can be explained as well by supposing that the earth turns daily on its axis and annually around the sun.[11]

Al-Biruni wrote about the astrolabe, the planisphere and the armillary sphere, besides inventing an astrolabe which he called cylindrical, but which is now referred to as orthographical.[12] Using the astrolabe and the presence of a mountain near a sea or flat plain, he calculated the earth circumference by solving a highly complex geodesic equation. With the aid of mathematics, he also enabled the direction of the Qibla to be determined from anywhere in the world. Max Meyerhof observed earlier this century that most of al-Biruni's mathematical works and many other writings have not been published yet.[13]

Al-Biruni was also very active in physics. He composed an extensive lapidary, describing a great number of stones and metals from the natural, commercial, and medical points of view.[14] He determined the specific gravity of eighteen precious stones, and laid down the principle that the specific gravity of an object corresponds to the volume of water it displaces.[15] To determine specific gravity, he used a 'conical vessel' (which al-Khazini calls the conical instrument of abu'l-Rayhan [al-Biruni]), to find the ratio of the weight of water displaced to the weight of a substance in air.[16] Al-Khazini in his Kitab Mizan al-Hikma (i.e. the Book of the balance of Wisdom) makes a detailed description of such an instrument and its uses (including by himself).[17] In his work on precious stones, he gave an account of the correspondence to be found between these and the metals, and determined their specific weights.[18]

Mieli explains how Al-Biruni weighted meticulously the substance he wanted to study, then dipped it into his conical instrument that was filled with water. He weighed the water which had been displaced by the immersed substance and which was escaping the instrument through a hole conveniently placed. The ratio between the weight of the body and that of the same water volume, gave the specific weight sought.[19] Many of the specific aspects of such an instrument owe to the fact that al-Biruni was extremely careful in ensuring his results were as accurate as possible. Al-Biruni carried out a series of measurements of specific weights, and summarised his findings in a number of tables. His results are very close to modern data, some of the deviations are explained by the impurity of the specimen and by temperature differences in his experiments.[20] He also determined the specific weight of some liquids, and established the differences in the specific weights of hot and cold water and fresh and salt water. He was the first in history to introduce checking tests in the practice of experiments.[19]







End Notes:

[1] G. Wiet; V. Elisseeff; P. Wolff; and J. Naudu: History of Mankind; op cit; p. 648.
[2] W. Durant: The Age of faith, Simon and Shuster, New York; 6th printing; 1950. p. 244.
[3] W. Durant: The Age; p. 244.
[4] G. Saliba: Al-Biruni; Dictionary of the Middle Ages, Ed Joseph Strayer; Vol 2. Charles Scribner's Sons, New York; 1980 ff. p.248.
[5] In W. Durant: The Age; p. 244.
[6] G. Sarton: Introduction; op cit; I; p. 707.
[7] G. Saliba: Al-Biruni; op cit; 248.
[8] G. Saliba: Al-Biruni; op cit; p.249.
[9] G. Saliba: Al-Biruni; op cit; p.249.
[10] Qanun, Maqalah, VIII, see also Ibn al-Nadim: Fihrist, Edition Flugel; 1857. p. 31.
[11] C. De Vaux: Les Penseurs de l'Islam; Vol 2; Geuthner; Paris; p. 217.
[12] G. Wiet; V. Elisseeff; P. Wolff; and J. Naudu: History of Mankind; p. 649.
[13] Max Meyerhof: Science and Medicine, in Sir Thomas Arnold and A. Guillaume edition: The Legacy of Islam, first edition; Oxford University Press; 1931; pp 311-55, at p. 332.
[14] W. Durant: The Age; op cit; p. 244.
[15] K. Bukhsh: 181; in W. Durant: The Age; op cit; p. 244.
[16] Most of the instruments designed by Muslim scientists whether in chemistry, surgery, physics or astronomy seem to be taken for granted, the fact, though, is that the design, and use of instruments by Muslim science is of absolutely crucial significance. Indeed, some of these instruments seem rather obsolete by today's standards of technical advance (some are still used, though,) yet, they had a crucial influence on the whole of modern science, and for various reasons. Moreover, the use of instruments for scientific experimentation, however ordinary it may seem, was a revolution in science, making experimental science the norm as against the usual Greek speculative approach. These were also the first steps on which science and scientists and designer built the modern equipments, techniques, and laboratories we have today.

The second point is the constant search for the perfect instrument for the sake of extreme accuracy which became the rule with Muslim science, and is the principal rule of modern science today.

[17] See Al-Khazini by R.E. Hall: Dictionary of Scientific Biography: Editor Charles C. Gillispie; Charles Scribner's Sons, New York, 1973, Vol VII, pp 335-51.
[18] G.Wiet; V. Elisseeff; P. Wolff; and J. Naudu: History of Mankind; p. 649.
[19] A. Mieli: La Science Arabe et son role dans l'Evolution Mondiale; Leiden, E, J. Brill, 1966. p. 101.
[20] M. Rozhanskaya (in collaboration with I.S. Levinova) Statics, in The Encyclopaedia of the History of Arabic Science; R. Rashed Ed; Routledge; London; 1996; pp 614-42. pp. 638-9.

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