The Arabs have been considered to be the founders of modern experimental science. They were relatively skillful chemists, for they discovered a number of new compounds (such as alcohol, aqua regia, nitric acid, and corrosive sublimate) and understood the preparation of mercury and of various oxides of metals. In medicine the Arabs based their investigations on those of the Greeks, [27] but made many additional contributions to the art of healing. They studied physiology and hygiene, dissected the human body, performed difficult surgical operations, used anaesthetics, and wrote treatises on such diseases as measles and smallpox. Arab medicine and surgery were studied by the Christian peoples of Europe throughout the later period of the Middle Ages.
[Illustration: INTERIOR OF THE MOSQUE OF CORDOVA The great mosque of Cordova, begun in the eighth century, was gradually enlarged during the following centuries to its present dimensions, 570 by 425 feet. The building, one of the largest in the world, has now been turned into a cathedral. The most striking feature of the interior is the forest of porphyry, jasper, and marble pillars supporting open Moorish arches. Originally there were 1200 of these pillars, but many have been destroyed.]
MATHEMATICS AND ASTRONOMY
The Arabs had a strong taste for mathematics. Here again they carried further the old Greek investigations. In arithmetic they used the so- called "Arabic" figures, which were probably borrowed from India. The Arabic numerals gradually supplanted in western Europe the awkward Roman numerals. In geometry the Arabs added little to Euclid, but algebra is practically their creation. An Arabic treatise on algebra long formed the textbook of the subject in the universities of Christian Europe. Spherical trigonometry and conic sections are Arabic inventions. This mathematical knowledge enabled the Arabs to make considerable progress in astronomy. Observatories at Bagdad and Damascus were erected as early as the ninth century. Some of the astronomical instruments which they constructed, including the sextant and the gnomon, are still in use. [28]
ROMANCE AND POETRY
In prose and verse there are two Moslem productions which have attained wide popularity in European lands. The first work is the Thousand and One Nights, a collection of tales written in Arabic and describing life and manners at the court of the Abbasids. The book, as we now have it, seems to have been composed as late as the fifteenth century, but it borrows much from earlier Arabic sources. Many of the tales are of Indian or Persian origin, but all have a thoroughly Moslem coloring. The second work is the Rubáiyát of the astronomer-poet of Persia, Omar Khayyam, who wrote about the beginning of the twelfth century. His Rubáiyát is a little volume of quatrains, about five hundred in all, distinguished for wit, satirical power, and a vein of melancholy, sometimes pensive, sometimes passionate. These characteristics of Omar's poetry have made it widely known in the western world. [29]
ARCHITECTURE
Painting and sculpture owe little to the Arabs, but their architecture, based in part on Byzantine and Persian models, reached a high level of excellence. Swelling domes, vaulted roofs, arched porches, tall and graceful minarets, and the exquisite decorative patterns known as "arabesques" make many Arab buildings miracles of beauty. Glazed tiles, mosaics, and jeweled glass were extensively used for ornamentation. From the first the Arab builders adopted the pointed arch; they introduced it into western Europe; and it became a characteristic feature of Gothic cathedrals. [30] Among the best-known of Arab buildings are the so-called "Mosque of Omar" at Jerusalem, [31] the Great Mosque of Cordova, and that architectural gem, the Alhambra at Granada. Many features of Moorish art were taken over by the Spaniards, who reproduced them in the cathedrals and missions of Mexico and California.
[Illustration: CAPITALS AND ARABESQUES FROM THE ALHAMBRA One of Mohammed's laws forbidding the use of idols was subsequently expanded by religious teachers into a prohibition of all imitations of human or animal forms in art. Sculptors who observed this prohibition relied for ornamentation on intricate geometrical designs known as arabesques. These were carved in stone or molded in plaster.]