The first name of importance which we encounter in the broken annals of Moorish occultism is a great one--that of the famous Geber, who flourished about 720-750, and who is reported to have penned upward of five hundred works upon the philosopher's stone and the elixir of life. In common with his fellow-alchemists, he appears to have failed signally in his search for those marvellous elements, but if he was unable to point the way to immortal life and boundless wealth, he is said to have given mankind the nitrate of silver, corrosive sublimate, and nitric acid. He believed that a preparation of gold would heal all diseases in both animals and plants, as well as in human beings, and that all metals were in a condition of chronic sickness in so far that they had departed from their natural and original state of gold. His works, all of which are in Latin, are not considered authentic, but his Summa Perfectionis, a manual for the alchemical student, has frequently been translated.
The Moorish alchemists taught that all metals are composed of varying proportions of mercury and sulphur. They laboured strenuously to multiply drugs out of the various mixtures and reactions of the few chemicals at their disposal, but although they believed in the theory of transmutation of metals they did not strive to effect it. It belonged to their creed rather than to their practice. They were a school of scientific artisans and experimentalists, first and last. They probably owed their alchemical knowledge to Byzantium, which in turn had received it from Egypt; or it may be that the Arabs drew their scientific inspiration at first hand from the land of the Nile, where the 'great art' of alchemy undoubtedly had its birth.
Astrology was also an important branch of occult study with the Moors of Spain, whose consideration of it greatly assisted the science of mathematics, especially that branch of it which still retains its Arabic name--algebra (al = the, jabara = to set, compute). It is probable that the Arabs first received an insight into the practice of foretelling events by the position of the planets at a given time from the Chaldeans, who undoubtedly were its earliest students. References to astrology are plentifully encountered in Spanish story, as the reader will have observed. But high as it stood in the estimation of the Moorish sages, it was still subservient to the grander and more mysterious art of magic, whereby the spirits of the air could be forced to do the will of the magus, and carry out his behests in four elements. Most unfortunately, we are almost entirely ignorant of the tenets of Moorish magic, owing probably to the circumstance that it was averse to the spirit of Islam. But we know that it was founded upon Alexandrian magic, and therefore recognized the principles of that art as laid down by the great Hermes Trismegistus, who was none other than the Egyptian Thoth, the god of writing, computation, and wisdom.