Most of these tracts have been inserted in the Theatrum Chemicum. They are in general plain and intelligible. In his treatise De Alchymia, for example, he gives a distinct account of all the chemical substances known in his time, and of the manner of obtaining them. He mentions also the apparatus then employed by chemists, and the various processes which they had occasion to perform. I may notice the most remarkable facts and opinions which I have observed in turning over these treatises.
He was of opinion that all metals are composed of sulphur and mercury; and endeavoured to account for the diversity of metals partly by the difference in the purity, and partly by the difference in the proportions of the sulphur and mercury of which they are composed. He thought that water existed also as a constituent of all metals.
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
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, 1. Thesaurum Alchymiæ Secretissimum. 2. Secreta Alchymiæ Magnalia. 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.
His writings display a degree of knowledge and extent of thought scarcely credible, if we consider the time when he wrote, the darkest period of the dark ages. In his small treatise De Mirabili Potestate Artis et Naturæ, he begins by pointing out the absurdity of believing in magic, necromancy, charms, or any of those similar opinions which were at that time universally prevalent. He points out the various ways in which mankind are deceived by jugglers, ventriloquists, &c.; mentions the advantages which physicians may derive from acting on the imaginations of their patients by means of charms, amulets, and infallible remedies: he affirms that many of those things which are considered as supernatural, are merely so because mankind in general are unacquainted with natural philosophy. To illustrate this he mentions a great number of natural phenomena, which had been reckoned miraculous; and concludes with several secrets of his own, which he affirms to be still more extraordinary imitations of some of the most singular processes of nature. These he delivers in the enigmatical style of the times; induced, as he tells us, partly by the conduct of other philosophers, partly by the propriety of the thing, and partly by the danger of speaking too plainly.
From an attentive perusal of his works, many of which have been printed, it will be seen that Bacon was a great linguist, being familiar with Latin, Greek, Hebrew, and Arabic; and that he had perused the most important books at that time existing in all these languages. He was also a grammarian; he was well versed in the theory and practice of perspective; he understood the use of convex and concave glasses, and the art of making them. The camera obscura, burning-glasses, and the powers of the telescope, were known to him. He was well versed in geography and astronomy. He knew the great error in the Julian calendar, assigned the cause, and proposed the remedy. He understood chronology well; he was a skilful physician, and an able mathematician, logician, metaphysician, and theologist; but it is as a chemist that he claims our attention here. The following is a list of his chemical writings, as given by Gmelin, the whole of which I have never had an opportunity of seeing: 1. Speculum Alchymiæ.26 2. Epistola de Secretis Operibus Artis et Naturæ et de Nullitate Magiæ. 3. De Mirabili Potestate Artis et Naturæ. 4. Medulla Alchymiæ. 5. De Arte Chemiæ. 6. Breviorium Alchymiæ. 7. Documenta Alchymiæ. 8. De Alchymistarum Artibus. 9. De Secretis. 10. De Rebus Metallicis. 11. De Sculpturis Lapidum. 12. De Philosophorum Lapide. 13. Opus Majus, or Alchymia Major. 14. Breviarium de Dono Dei. 15. Verbum abbreviatum de Leone Viridi. 16. Secretum Secretorum. 17. Tractatus Trium Verborum. 18. Speculum Secretorum. A number of these were collected together, and published at Frankfort in 1603, under the title of “Rogeri Baconis Angli de Arte Chemiæ Scripta,” in a small duodecimo volume. The Opus Majus was published in London in 1733, by Dr. Jebb, in a folio volume. Several of his tracts still continue in manuscript in the Harleian and Bodleian libraries at Oxford. He considered the metals as compound of mercury and sulphur. Gmelin affirms that he was aware of the peculiar nature of manganese, and that he was acquainted with bismuth; but after perusing the whole of the Speculum Alchymiæ, the third chapter of which he quotes as containing the facts on which he founds his opinion, I cannot find any certain allusion either to manganese or bismuth. The term magnesia indeed occurs, but nothing is said respecting its nature: and long after the time of Paracelsus, bismuth (bisematum) was considered as an impure kind of lead. That he was acquainted with the composition and properties of gunpowder admits of no doubt. In the sixth chapter of his epistle De Secretis Operibus Artis et Naturæ et de Nullitate Magiæ, the following passage occurs:
“For sounds like thunder, and coruscations like lightning, may be made in the air, and they may be rendered even more horrible than those of nature herself. A small quantity of matter, properly manufactured, not larger than the human thumb, may be made to produce a horrible noise and coruscation. And this may be done many ways, by which a city or an army may be destroyed, as was the case when Gideon and his men broke their pitchers and exhibited their lamps, fire issuing out of them with inestimable noise, destroyed an infinite number of the army of the Midianites.” And in the eleventh chapter of the same epistle occurs the following passage: “Mix together saltpetre, luru vopo vir con utriet, and sulphur, and you will make thunder and lightning, if you know the method of mixing them.” Here all the ingredients of gunpowder are mentioned except charcoal, which is doubtless concealed under the barbarous terms luru vopo vir con utriet.
But though Bacon was acquainted with gunpowder, we have no evidence that he was the inventor. How far the celebrated Greek fire, concerning which so much has been written, was connected with gunpowder, it is impossible to say; but there is good evidence to prove that gunpowder was known and used in China before the commencement of the Christian era; and Lord Bacon is of opinion that the thunder and lightning and magic stated by the Macedonians to have been exhibited in Oxydrakes, when it was besieged by Alexander the Great, was nothing else than gunpowder. Now as there is pretty good evidence that the use of gunpowder had been introduced into Spain by the Moors, at least as early as the year 1343, and as Roger Bacon was acquainted with Arabic, it is by no means unlikely that he might have become acquainted with the mode of making the