Abu Al Fath Al Khazini (d. 550 H) أبو الفاتح الخازني
He is Abu Al-Fath `Abd al-Rahamn Al-Khazin, or Al-Khazini: a man of wisdom, an astronomer and an engineer. Of Greek origin, he grew under the care of his master, Ali Al-Khazin al-Marwazi and studied in Marw city of Khurasan where he learnt from leading figures of astronomy, mathematics and physics. Thus, he gained expertise in those sciences while not yet a free man. He evoked the admiration and astonishment of many when he came out with his book, Meezan Al-Hikmah, which was a marvel in the fields of mechanics, physics and hydrostatics. Alongside these sciences, he was also interested in astronomy and he determined the direction of the Qiblah in most Muslim states.
He based his determination of the Qiblah on his readings from Ibn al-Haytham and Al-Beiruni. Most historians of science are unanimous that Al-Khazini stands as an authority in physics for all generations, that he even surpassed his teachers – Ibn Sina (Avicenna), Al-Beiruni and Ibn al-Haytham (who was the first to attempt the discovery of the speed of light) – all of whom had discussed gravity, albeit not very scientifically and accurately. He outstripped them, in general, in this discipline as well, and particularly in Dynamics and Hydrostatics. His own theories in these two fields are taught to this day. In astronomy, he excelled in making tables known as the Sinjari tables. He devoted most of his time to the study of Hydrostatics and improved the instrument that was designed by Al-Beiruni which determined the specific weight of liquids: an undertaking in which he attained a high degree of accuracy. He spoke during his studies about the resistance which bodies immersed in liquids generally encounter.
He arrived at a formula that determines the abstract weight of masses composed of two different materials. He preceded Torshilly in referring to air as matter with mass, and stating that air has mass and capillary action similar to liquids. He also stated that weights of immersed masses are less than their real weights. He also explained that the Archimedes’ principle applies to gases in addition to liquids; such revelations paved the way for the invention of the barometer, air-vacuums, and pumps. He also wrote on theories of light, and calculated the deflection of light upon its passage through air. He made great efforts in his work on specific weights and gravity and demonstrated experimentally how all parts of the body direct their descent towards the centre of the earth due to gravity; showing that the variation in gravitational pull on different segments of the descending body result from the variation in the distance between the respective segments and the centre of the earth. He based his inferences on experiments and scientific calculations. Thus, he preceded Newton by several centuries, though not acknowledged by the West. He authored many books including the Mizan Al-Hikmah which came in eight volumes. It spoke about hydrostatics, weights, theories on gravity, Archimedes’ and Menelaus’s views on hydrostatics, specific weights of different materials, and astronomy. It solved problems, stated exercises and listed the specific weights of different materials in tabulated form. Al-Khazini discussed the relation between the speed at which a body falls to the distance and time it takes; he gave that in a formula for discovering which scientists in the West – like Galileo, Newton, and others – claimed credit several centuries later. His other books include those on conical instruments, Sinjari astronomical tables etc.
He was a man of fine Islamic character, an ascetic and a self-reliant person. When his fame spread, the ruler of the time sent him 1000 Dinars. He accepted ten and returned the rest saying, “I have no need for the rest. My entire expenses are three Dinars per year.” A princes also sent him 1000 Dinars, but he refused all of it.
(Sources: Tatimmah Mizan Al-Hikmah Al-I`lam (Zarkali), Mu`jam al-Mu’allifieen, Mafaheem al-Islamiyyah - MS)