"Albertus Magnus lectured in , and great numbers of students flocked to hear him. He skilfully managed to escape the persecution which befell so many of his brother monks who dabbled in the occult art, and was high in the odor of sanctity. His principal writings were the following: "De Rebus Metallicis et Mineralibus;" "De Alchymia;" "Secretorum Tractatus;" "Breve Compendium de Ortu Metallorum;" "Concordantia;" "Philosophorum de Lapide." ...He was the first to use the term "affinitas" to designate the cause of the combination of the metals with sulphur and other elements. The term "" was also first used by him. He regarded the transmutation of the metals as an assured possibility. He did not regard the metals as distinctly differing substances, but varieties of the same species. "The metals are all essentially identical; they differ only in form. Now, the form brings out accidental causes, which the experimenter must try to discover and remove, as far as possible. Accidental causes impede the regular union of sulphur and mercury; for every metal is a combination of sulphur and mercury. A diseased womb may give birth to a weakly, leprous child, although the seed was good; the same is true of the metals which are generated in the bowels of the earth, which is a womb for them; any cause whatever, or local trouble, may produce an imperfect metal. When pure sulphur comes in contact with pure mercury, after more or less time, and by the permanent action of nature, gold is produced." His views are in the main those of Geber, though he adds water to mercury and sulphur as one of the constituents of the metals."