ALCHEMY 261 discovered that a metal when oxidized (or, as he called it, calcined) increases in weight ; a fact rediscovered 1,000 years later by Europeans, and then brought to bear in the destruction of the absurd phlogiston hypothesis then prevail- ing. He describes the absorption and evolution of gases by and from liquids and solids, and gives singularly clear instructions in regard to nitration, distillation, sublimation, water and sand baths, cupels of bone earth, and various other chemical operations. He made nitric acid by distilling a mixture of blue vitriol, alum, and saltpetre, and aqua regia by adding sal am- moniac to nitric acid ; he could then obtain gold in solution, and so solved the great problem to which before his time all the efforts of alche- mists had been vainly directed, the manufacture of gold in a potable state. No wonder that Ro- ger Bacon speaks of him as the magister magis- terium. Ehazes, head physician to the hospital of Bagdad, invented about a century later the preparation of sulphuric acid by the distillation of green vitriol, as Nordhausen vitriol is now prepared. He was also the first to make abso- lute alcohol by distilling spirits over quicklime. Achild Bechil distilled a mixture of urine, clay, lime, and charcoal, and obtained what he called an artificial carbuncle, as it shone in the dark like the moon ; it was phosphorus, rediscovered by Brand in Hamburg in 1669. The taste for this class of pursuits diffused itself over Europe by two channels, the scientific Italians, Ger- mans, Englishmen, and Frenchmen who visited Spain frequently, and the Greeks who fled from the Mussulman invasion. Already in the 10th century we find traces of alchemy in different European countries ; but it was most ardently pursued in the 15th, 16th, and 17th centuries, in the course of which many deceptive and imaginary sciences became associated with it, such as theosophy, cabala, chiromancy, necro- mancy, astrology, and magic. Besides the great number of those honest alchemists who deceived the credulous masses by their own confidence expressed in mysterious and sanguine writings, there was a class of impostors who travelled about extorting money from the credulous. Ed- ward III. of England paid large amounts of money to the celebrated alchemist Raymond Lully, and Henry VI. in 1440 gave several patents for the making of gold. Rudolph II. of Germany founded in Prague a regular alchemistic university. Augustus I. of Saxony himself worked, with his wife Anna as assistant, in the pursuit of gold-making, and kept besides two alchemists on a regular salary. Duke Frederick of Wurtemberg, who died in 1608, wasted all the revenue of his land in experi- ments. Christian IV. of Denmark appointed Harbach, the director of the mint in Copen- hagen, as his private alchemist. The emperor Ferdinand III., Duke John Philip of Mentz, and a great many others could be enumerated ; and it is strange that notwithstanding numerous glaring deceptions, and revelations of the most contemptible dishonesty, which were often pun- ished by public executions, the belief in the possibility of making gold maintained itself. When Bottger escaped from Berlin in 1703, he was placed in prison in Dresden by the elector of Saxony, to compel him to make gold ; he suc- ceeded, however, in discovering there the much more valuable art of making porcelain. Even the celebrated astronomer Tycho Brahe occu- pied himself with attempts to make gold, but with the purpose of obtaining means to pros- ecute his astronomical investigations on a larger scale. Until the end of the 17th century all chemical labors were chiefly directed to the same end, though many practised this art for medical purposes. Among the many authors on alchemy must be mentioned Albertus Mag- nus, Roger Bacon, Arnold de Villanova, Ray- mond Lully, Basilius Valentinus, Theophrastus Paracelsus, Libavius, Becher, Kunckel, and Glauber. During the 18th century it is difficult to distinguish between an alchemist and a true chemist, as many really scientific men were kept in error by believing Jaffar's false theory that all metals were compound bodies. Even as late as 1772, Schroder, professor in Marburg, and Wenzel, a distinguished chemist in Freiberg, defended the theory of the transmutation of metals. Guyton de Morveau firmly believed that silver could be changed into gold simply by melting with it sulphuret of antimony and arsenic ; but it was afterward discovered that all the gold thus obtained could be accounted for as being present beforehand in the materials used. In 1796 two German physicians in West- phalia founded a society for the purpose of investigating the transmutation of metals; many branch societies were formed, which were flourishing in 1804, and still in existence in 1820. In a text book of chemistry (Baudri- mont, Traite de chimie) published so lately as 1844, it is stated that a certain "Mr. Javary has obtained very surprising results by following the prescriptions of the ancient alchemists, so that there is hope of at last seeing the great work succeed." In a still later publication (1856) Fiffereau affirms that the metals are compound bodies, and that silver can be changed into gold. The alchemists' articles of faith were as follows: "1. There exists a preparation, solid in form and red of color, called the philoso- pher's stone, the grand elixir (major magis- terium), the red tincture, which, when it is placed in very small doses on melted liquid silver, mercury, lead, or some other common metal, causes a transmutation of the same into gold. 2. The same preparation, used in very small doses as a medicine, cures all diseases, rejuvenates the old, and prolongs- life ; where- fore it is called the panacea of life, and since it contains the essence of gold, aurum potabile. 3. There is another preparation of a white color, called the stone of the second degree, the little elixir (minor magister ium), the white tincture, which is equal to the first in half a degree of perfection, and changes the common metals into silver."