He was acquainted with the water-bath, employed alembics for distillation, and aludels for sublimation; and he was in the habit of employing various lutes, the composition of which he describes.
He mentions alum and caustic alkali, and seems to have known the alkaline basis of cream of tartar. He knew the method of purifying the precious metals by means of lead and of gold, by cementation; and likewise the method of trying the purity of gold, and of distinguishing pure from impure gold.
He mentions red lead, metallic arsenic, and liver of sulphur. He was acquainted with green vitriol and iron pyrites. He knew that arsenic renders copper white, and that sulphur attacks all the metals except gold.
It is said by some that he was acquainted with gunpowder; but nothing indicating any such knowledge occurs in any of his writings that I have had an opportunity of perusing.[25]
[25] It is curious that Olaus Borrichius omits Albertus Magnus in the list of alchymistical writers that he has given.
2. Albertus is said to have had for a pupil, while he taught in Paris, the celebrated Thomas Aquinas, a Dominican, who studied at Bologna, Rome, and Naples, and distinguished himself still more in divinity and scholastic philosophy than in alchymy. He wrote,
3. De Esse et Essentia Mineralium; and perhaps some other works, which I have not seen.
These works, so far as I have perused them, are exceedingly obscure, and in various places unintelligible. Some of the terms still employed by modern chemists occur, for the first time, in the writings of Thomas Aquinas. Thus the term _amalgam_, still employed to denote a compound of mercury with another metal, occurs in them, and I have not observed it in any earlier author.
3. Soon after Albertus Magnus, flourished Roger Bacon, by far the most illustrious, the best informed, and the most philosophical of all the alchymists. He was born in 1214, in the county of Somerset. After studying in Oxford, and afterwards in Paris, he became a cordelier friar; and, devoting himself to philosophical investigations, his discoveries, notwithstanding the pains which he took to conceal them, made such a noise, that he was accused of magic, and his brethren in consequence threw him into prison. He died, it is said, in the year 1284, though Sprengel fixes the year of his death to be 1285.