and began to grow towards fruition. Very great advances were made in mathematical, medical and physical science. The clumsy Roman numerals were ousted by the Arabic figures we use to this day and the zero sign was first employed. The very name algebra is Arabic. So is the word chemistry. The names of such stars as Algol, Aldebaran and Boötes preserve the traces of Arab conquests in the sky. Their philosophy was destined to reanimate the medieval philosophy of France and Italy and the whole Christian world.
The Arab experimental chemists were called alchemists, and they were still sufficiently barbaric in spirit to keep their methods and results secret as far as possible. They realized from the very beginning what enormous advantages their possible discoveries might give them, and what far-reaching consequences they might have on human life. They came upon many metallurgical and technical devices of the utmost value, alloys and dyes, distilling, tinctures and essences, optical glass; but the two chief ends they sought, they sought in vain. One was “the philosopher’s stone”—a means of changing the metallic elements one into another and so getting a control of artificial gold, and the other was the elixir vitœ, a stimulant that would revivify age and prolong life indefinitely. The crabbed patient experimenting of these Arab alchemists spread into the Christian world. The fascination of their enquiries spread. Very gradually the activities of these alchemists became more social and co-operative. They found it profitable to exchange and compare ideas. By insensible gradations the last of the alchemists became the first of the experimental philosophers.
The old alchemists sought the philosopher’s stone which was to transmute base metals to gold, and an elixir of immortality; they found the methods of modern experimental science which promise in the end to give man illimitable power over the world and over his own destiny.