Alchemy is the science of the four elements, which are to be found in all created substances, but are not of the vulgar kind. The whole practice of the art is simply the conversion of these elements into one another. The seed and matter of every metal is mercury, as it is decocted and otherwise prepared in the bowels of the earth, and each of them can be reduced into this _prima materia_, by the help of which they are also, one and all, susceptible of augmentation and multiplication, even to infinity. POPE JOHN XXII. This pontiff is claimed as an adept by the alchemists, a fact which is denied, but not disproved, by his orthodox biographers. That he believed in the power of magic is shown by the accusation which he directed against Géraud, Bishop of Cahors, whom he accredited with the design of poisoning him, together with the entire college of cardinals, and with having in particular contrived sorceries and diabolical enchantments against all of them. He was the contemporary of Raymond Lully and Arnold de Villanova, and is said to have been the pupil and friend of the latter. Nevertheless, the mischief occasioned at that period by the impostures of pretended alchemists led him to issue a bull condemning the traders in this science as charlatans who promised what they were unable to perform. Hermetic writers assert that this bull was not directed against veritable adepts, and his devotion to his laboratory at Avignon seems a fairly established fact. Franciscus Pagi, in his _Breviarum de Gestis Romanorum Pontificum_, has the following passage:--_Joannes scripsit quoque latino sermone artem metallorum transmutorium; quod opus prodiit Gallici incerto translatore Lugduni, anno 1557 in 8vo_. It is allowed that he was a writer on medicine. His _Thesaurus Pauperum_, a collection of recipes, was printed at Lyons in 1525, and he was the author of a treatise on diseases of the eye, and of another on the formation of the fœtus. He was born at Cahors, according to the general opinion, of poor but reputable parents; he showed at an early period his skill in law and in the sciences. The circumstances of his life are exceedingly obscure until his consecration as Bishop of Fréjus in 1300. Subsequently he was promoted to the see of Avignon, and Clement V. created him cardinal-bishop of Porto. He was raised to the pontificate at Lyons, and reigned at Avignon till his death in 1334. He left behind him in his coffers the sum of eighteen million florins in gold and seven millions in jewels, besides valuable consecrated vessels. Alchemists attribute these vast treasures to his skill in their science, and assert in addition that he manufactured two hundred ingots, apparently on a single occasion. By a calculation of one of his biographers, this quantity of the precious metal was equivalent to £660,000, British sterling. A treatise entitled “The Elixir of the Philosophers, or the Transmutatory Art of Metals,” is attributed to him. It was translated