262 A BRIEF SURVEY OF HUMAN HISTORY

nurses. They produced a number of versatile and profound
scholars. They made permanent contributions to European
science and vocabularies (e.g. words like soja, tariff, algebra,
etc.). Omar Khayyam who is celebrated as a Persian poet
wrote in Arabic a book of the first rank on Algebra. Sum-
ming up the scientific contributions of the Arabs, Baron
Carra de Vaux observes :

" They taught the use of ciphers, although they did not invent
them, and thus became the founders of the arithmetic of everyday
life; they made algebra an exact science and developed it con-
siderably and laid the foundation of analytical geometry; they
were indisputably the founders of plane and spherical trigono-
metry which, properly speaking, did not exist among the Greeks.
In astronomy they made a number of valuable observations.
They preserved for us in their translations a number of Greek
works, the originals of which have been lost—for which services
we cannot be too grateful to them. Another reason for our in-
terest in Arab science is the influence it has had in the West.
The Arabs kept alive the higher intellectual life and the study
of science in a period when the Christian West was fighting des-
perately with barbarism. The zenith of their activity may be
placed in the ninth and tenth centuries, but it was continued down
to the fifteenth. From the twelfth century every one in the West
who had any taste for science, some desire for light, turned to
the East or to the Moorish West. At this period the works of
Arabs began to be translated as those of the Greeks had previously
been by them. The Arabs thus formed a bond of union, a con-
necting link between ancient culture and modern civilization.
When at the Renaissance the spirit of man was once again filled
with zeal for knowledge and stimulated by the spark of genius,
tf it was able to set promptly to work, to produce and invent,
it was because the Arabs had preserved and perfected various
branches of knowledge, kept the spirit of research alive and eager
and maintained it pliant and ready for future discoveries."