It is only what might have been expected, however, from { 46} Roger Bacon's training that he should have made great progress in the physical sciences. At the University of Paris his favorite teacher was Albertus Magnus, who was himself deeply interested in all the physical sciences, though he was more concerned with the study of chemical problems than of the practical questions which were to occupy his greatest pupil. There is no doubt at all that Albertus Magnus accomplished a great amount of experimental work in chemistry and had made a large series of actual observations. He was a theologian as well as a philosopher and a scientist. Some idea of the immense industry of the man can be obtained from the fact that his complete works as published consist of some twenty large folio volumes, each one of which contains on the average at least 500,000 words.
Among these works are many treatises relating to chemistry. The titles of some of them will serve to show how explicit was Albert in his consideration of various chemical subjects. He has treatises concerning Metals and Minerals; concerning Alchemy; A Treatise on the Secret of Chemistry; A Concordance, that is a Collection of observations from many sources with regard to the Philosopher's Stone; A Brief Compend on the Origin of the Metals; A Treatise on Compounds; most of these are to be found in his works under the general heading "Theatrum Chemicum."
It is not surprising for those who know of Albert's work, to find that his pupil Roger Bacon defined the limits of chemistry very accurately and showed that he understood exactly what the subject and methods of investigation must be, in order that advance should be made in it. Of chemistry he speaks in his "Opus Tertium" in the following words: "There is a science which treats of the generation of things from their elements and of all inanimate things, as of the elements and liquids, simple and compound, common stones, gems and marble, gold and other metals, sulphur, salts, pigments, lapis lazuli, minium and other colors, oils, bitumen, and infinite more of which we find nothing in the books of Aristotle; nor are the natural philosophers nor any of the Latins acquainted with these things."