The History of Chemistry (Vol.1&2). Thomas Thomson

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СКАЧАТЬ containing oxide of gold or silver within, and the bottom shut with wax: by these means the gold or silver wanted is introduced during the process, and considered as a product of the operation.

      Sometimes they have a solution of silver in nitric acid, or of gold in aqua regia, or an amalgam of gold or silver, which being adroitly introduced, furnishes the requisite quantity of metal. A common exhibition was to dip nails into a liquid, and take them out half converted into gold. The nails consisted of one-half gold, neatly soldered to the iron, and covered with something to conceal the colour, which the liquid removed. Sometimes they had metals one-half gold the other half silver, soldered together, and the gold side whitened with mercury; the gold half was dipped into the transmuting liquid and then the metal heated; the mercury was dissipated, and the gold half of the metal appeared.22

      As the alchymists were assiduous workmen—as they mixed all the metals, salts, &c. with which they were acquainted, in various ways with each other, and subjected such mixtures to the action of heat in close vessels, their labours were occasionally repaid by the discovery of new substances, possessed of much greater activity than any with which they were previously acquainted. In this way they were led to the discovery of sulphuric, nitric, and muriatic acids. These, when known, were made to act upon the metals; solutions of the metals were obtained, and this gradually led to the knowledge of various metalline salts and preparations, which were introduced with considerable advantage into medicine. Thus the alchymists, by their absurd pursuits, gradually formed a collection of facts, which led ultimately to the establishment of scientific chemistry. On this account it will be proper to notice, in this place, such of them as appeared in Europe during the darker ages, and acquired the highest reputation either on account of their skill as physicians, or their celebrity as chemists.23

      1. The first alchymist who deserves notice is Albertus Magnus, or Albert Groot, a German, who was born, it is supposed, in the year 1193, at Bollstaedt, and died in the year 1282.24 When very young he is said to have been so remarkable for his dulness, that he became the jest of his acquaintances. He studied the sciences at Padua, and afterwards taught at Cologne, and finally in Paris. He travelled through all Germany as Provincial of the order of Dominican Monks, visited Rome, and was made bishop of Ratisbon: but his passion for science induced him to give up his bishopric, and return to a cloister at Cologne, where he continued till his death.

      Albertus was acquainted with all the sciences cultivated in his time. He was at once a theologian, a physician, and a man of the world: he was an astronomer and an alchymist, and even dipped into magic and necromancy. His works are very voluminous. They were collected by Petr. Jammy, and published at Leyden in twenty-one folio volumes, in 1651. His principal alchymistical tracts are the following: 1. De Rebus Metallicis et Mineralibus. 2. De Alchymia. 3. Secretorum Tractatus. 4. Breve Compendium de Ortu Metallorum. 5. Concordantia Philosophorum de Lapide. 6. Compositum de Compositis. 7. Liber octo Capitum de Philosophorum Lapide.

      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 СКАЧАТЬ