"العراق والخليج الفارسي" [ظ‎‎١‎٧‎٨] (٨٦٢/٣٦١)

250 HISTORY
Physical Sciences
The sciences in which the Arabs succeeded best were mathematics,
astronomy, medicine, and geography. The arithmetic and geometry
of Mohammed ibn Musa (Khwarizmi, 780-850) was translated
into Latin and remained a standard text-book of Europe till the
sixteenth century: this work introduced to Europe the Arabic
numeral system based on the use of the zero cipher, borrowed from
the Hindus. His astronomical tables were translated by Adelard of
Bath (1126). The astronomers of Mamun’s observatory at Baghdad,
using quadrant, astrolabe, dial, and globes, made accurate determina
tions of latitude and longitude, verified the precession of the equi
noxes, and even measured the length of a terrestrial degree on the flat
plains of the Jazira, finding a length of 56! miles (an excess of only
2,877 ft.). From the astrology of Baghdad, ever a Mesopotamian
interest, the knowledge of the law of tides reached Europe.
Medicine, partly inspired by Nestorian teachers, was helped by the
institution of hospitals, such as that of Harun at Baghdad, where
Razi (Rhazes, 850-923) wrote his summary of medical knowledge, the
Continens. This with the Canon of Ibn Sina (Avicenna, 980-1037)
served in Latin translations as the basis of the medical knowledge
of Europe from the twelfth century to the seventeenth. Razi wrote
a noted monograph on the treatment of small-pox and measles which
contains the first clinical account of small-pox, while Ibn Sina
recognized the contagious nature of phthisis.
In chemistry the Arabs were less successful. Their observation
was sound, but their deductions and formulations of general prin
ciples were weak. Also they were led astray by the search for the
Philosopher’s Stone and the Elixir of Life, errors which they trans
mitted to Europe. But Jabir of Kufa (c. 776) described the processes
of calcination and reduction, and the Persian Biruni determined the
specific gravity of eighteen precious stones and metals.
Geography —technically based on Ptolemy and sound astronomical
observations—was encouraged by the wide span of the Moslem world,
the tradition of pilgrimage, and the long journeys of traders. The
imperial postmasters wrote itineraries with topographical and eco
nomic details. Khwarizmi made a map of the world and the heavens
with the help of sixty-nine assistants. Systematic geographies of the
Moslem world were written in the tenth century a.d., complete with
coloured maps, by Ibn Hawqal and others; they contain the modern
notion of the geographical region treated in all its aspects. The