apparently solitary instance, and one which, in its own day, had no
effect; for the fact was forgotten, and rediscovered centuries after by
Tycho Brahe. To Albatani, however, we owe two really valuable
heirlooms. The one is the use of the sine, or half-chord of the double
arc, instead of the chord of the arc itself, which had been employed by
the Greek astronomers; the other, of even more practical benefit, was
the introduction of the present decimal arithmetic, instead of the
troublesome sexagesimal arithmetic of the Greeks. These ten digits,
however, seem, says Professor Whewell, by the confession of the Arabians
themselves, to be of Indian origin, and thus form no exception to the
sterility of the Arabian genius in scientific inventions. Nevertheless
we are bound, in all fairness, to set against his condemnation of the
Arabs Professor De Morgan's opinion of the Moslem, in his article on
Euclid: "Some writers speak slightingly of this progress, the results
of which they are too apt to compare with those of our own time. They
ought rather to place the Saracens by the side of their own Gothic
ancestors; and making some allowance for the more advantageous
circumstances under which the first started, they should view the second
systematically dispersing the remains of Greek civilisation, while the
first were concentrating the geometry of Alexandria, the arithmetic and
algebra of India, and the astronomy of both, to form a nucleus for the
present state of science."

To this article of Professor De Morgan's on Euclid, {2} and to Professor
Whewell's excellent "History of the Inductive Sciences," from which I,
being neither Arabic scholar nor astronomer, have drawn most of my facts
about physical science, I must refer those who wish to know more of the
early rise of physics, and of their preservation by the Arabs, till a
great and unexpected event brought them back again to the quarter of the
globe where they had their birth, and where alone they could be