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'Abd al-Rahman al-Khazini' () (flourished 1115–1130) was a Byzantine Muslim scientist, physicist, astronomer, alchemist, biologist, mathematician and philosopher from Merv, Greater Khorasan, Eastern Persia (in modern day Turkmenistan), who made important contributions to physics and astronomy.^[1] He is considered to be the greatest scholar from the city of Merv.Zaimeche, p. 5.
Robert E. Hall wrote the following on al-Khazini:

Contents

Early life

Works

''Sinjaric Tables''

''The Book of the Balance of Wisdom''

''Treatise on Instruments''

Evolution

See also

Notes

References

Primary sources

Early life

Al-Khazini was a Byzantine Greek^[2] slave of the Seljuq Turks, who was taken to Merv after the Seljuq victory over the Byzantine Emperor Romanus IV.^[3] His master, al-Khazin, gave him the best possible education in mathematical and philosophical subjects. Al-Khazini was also a pupil of the famous Persian poet, mathematician, astronomer and philosopher Omar Khayyám (1048-1131), who was living in Merv at the time.^[4]
Al-Khazini later became a mathematical practitioner under the patronage of the Seljuk court, under Sultan Ahmed Sanjar. Little else is known about his life, but it is known that he refused rewards and handed back 1000 dinars sent to him by the wife of an Emir, and that he usually lived on 3 dinars a year.

Works

''Sinjaric Tables''

Included in his astronomical treatise ''Az-Zīj As-Sanjarī'' or ''Sinjaric Tables'', Al-Khazini gave a description of his construction of a 24 hour water clock designed for astronomical purposes, and the positions of 46 stars computed from the date given in the ''Almagest'' for the year 500 AH (1115-16 CE). He also computed tables for the observation of celestial bodies at the latitude of Merv.^[5][6]

''The Book of the Balance of Wisdom''

Al-Khazini is better known for his contributions to physics in his treatise ''The Book of the Balance of Wisdom'', completed in 1121, which remained an important part of Muslim physics. The book contains studies of the hydrostatic balance, its construction and uses, and the theories of statics and hydrostatics that lie behind it, as developed by his predecessors and contemporaries.^[7] It also contains descriptions on the instruments of his predecessors, including the araeometer of Pappus and the pycnometer flask of al-Biruni, as well as his own hydrostatic balance and specialized balances and steelyards.^[8]
The first of the book's eight chapters deals with his predecessors' theories on the centre of gravity, including Al-Razi (Latinized as ''Rhazes''), Abū Rayhān al-Bīrūnī, and Omar Khayyám. He also draws attention to the failure of the ancient Greeks to clearly differentiate between force, mass, and weight, and he goes on to show awareness of the weight of the air, and of its decrease in density with altitude.Hill, p. 61. (cf. Zaimeche, p. 5.) The strict definition for a specific weight is given by Al-Khazini in ''The Book of the Balance of Wisdom'':
After extensive experimentation, Al-Khazini records the specific gravities of fifty substances, including various stones, metals, liquids, salts, amber, and clay. The accuracy of his measures were impressive and comparable to modern values. In another experiment, Al-Khazini discovered that there was greater density of water when nearer to the Earth's centre, which was later proven by Roger Bacon in the 13th century.^[9]
Al-Khazini defines heaviness in traditional Aristotelian terms as an inherent property of heavy bodies:
On the basis that there is denser air when nearer to the centre of the Earth (derived from the Archimedes principle),^[10] and that the weight of heavy bodies increase as they are farther from the centre of the Earth (derived from al-Quhi and Alhacen's theories that weight varies with the distance from the centre of the Earth), al-Khazini postulated that the gravity of a body varies with its distance from the centre of the Earth:Professor Mohammed Abattouy (2002), "The Arabic Science of weights: A Report on an Ongoing Research Project", ''The Bulletin of the Royal Institute for Inter-Faith Studies'' '4', p. 109-130:

It appears that what al-Khazini meant by "gravity" ("''thiql''" in Arabic) is both an idea similar to the modern concept of gravitational potential energy,^[11]
and the moment of a force relative to a point (both meanings were derived from al-Quhi and Alhacen).Rozhanskaya and Levinova (1996), p. 622. In either case, al-Khazini appears to have been the first to propose that the gravity of a body varies with its distance from the centre of the Earth.^[12] In his first sense of the word "gravity", the concept was not considered again until Newton's law of universal gravitation in the 18th century,^[13][14] but in his second sense of the word, the concept was considered again by Jordanus Nemorarius in the 13th century.
N. Khanikoff, an early translator and commentator of al-Khazini's work, summarized his ideas regarding gravity as follows:

''Treatise on Instruments''

His ''Risala fi'l-alat'' (''Treatise on Instruments'') has seven parts describing different instruments: the triquetrum, dioptra, a triangular instrument, the quadrant and sextant, instruments involving reflection, and the astrolabe.^[15]

Evolution

Al-Khazini wrote the following on evolution in alchemy and biology, and how they were perceived by natural philosophers and common people in the Islamic world at the time:

See also

★ Islamic science

★ Islamic astronomy

★ Islamic Golden Age

★ Muslim inventions

★ Zij

Notes

1. Abd Al-Rahman Al-Khazini, ''Science and Its Times'' (2006). Thomson Gale.
2. Kennedy, ''Islamic Astronomical Tables,'' p. 7.
3. Klotz, "Multicultural Perspectives in Science Education: One Prescription for Failure".

4. Rosenfeld, p. 686-688.
5. Sarton, p. 565.
6. Kennedy, ''Islamic Astronomical Tables'', pp. 7, 37-39
7. Mariam Rozhanskaya, "On a Mathematical Problem in al-Khazini's ''Book of the Balance of Wisdom''", in David A. King and George Saliba, ed., ''From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E. S. Kennedy'', Annals of the New York Academy of Science, vol. 500 (1987), p. 427
8. Robert E. Hall (1973). "Al-Khazini", ''Dictionary of Scientific Biography'', Vol. VII, p. 346.
9. Max Meyerhof (1931), "Science and Medicine", in Sir T. Arnold and A. Guillaume, ''Legacy of Islam'', p. 342, Oxford University Press. (cf. Zaimeche, p. 7)
10. Marshall Clagett, ''The Science of Mechanics in the Middle Ages'', (Madison, Univ. of Wisconsin Pr., 1961), pp. 65-68
11. Rozhanskaya and Levinova (1996), p. 621:

12. Rozhanskaya and Levinova (1996), p. 622:

13. Rozhanskaya and Levinova (1996), p. 622:

14. Zaimeche, p. 7.
15. Robert E. Hall (1973). "Al-Biruni", ''Dictionary of Scientific Biography'', Vol. VII, p. 338.

References

★ Donald Routledge Hill (1993). ''Islamic Science and Engineering''. Edinburgh University Press.

★ E. S. Kennedy (1956). ''A Survey of Islamic Astronomical Tables,'' (Transactions of the American Philosophical Society, New Series, 46, 2.) Philadelphia.

★ Irving M. Klotz (1993). "Multicultural Perspectives in Science Education: One Prescription for Failure", ''Phi Delta Kappan'' '75'.

★ Mariam Rozhanskaya and I. S. Levinova (1996), "Statics", in Roshdi Rashed, ed., ''Encyclopedia of the History of Arabic Science'', Vol. 2. London and New York: Routledge.

★ Boris Rosenfeld (1994). Review of Mariam Mikhailovna Rozhanskaya, ''Abu'l-Fath Abd al-Rahman al-Khazini (XII Century)'', ''Isis'' '85' (4), p. 686-688.

★ George Sarton (1927). ''Introduction to the History of Science'', vol. I. The Carnegie Institution, Washington.

★ Salah Zaimeche PhD (2005). Merv, Foundation for Science Technology and Civilization.

Primary sources

★ ''Books 10 - 12 of Al Khazini's epitome of the Zij as-Sanjari (transcription) '' (Classical Arabic)