with an entreaty that he would perform the process of transmutation before him. The stranger replied, that he was not allowed to do so, and went away. After his departure, Helvetius procured a crucible and a portion of lead, into which, when in a state of fusion, he threw the stolen grain from the philosopher’s stone. He was disappointed to find that the grain evaporated altogether, leaving the lead in its original state.

Some weeks afterwards, when he had almost forgotten the subject, he received another visit from the stranger. He again entreated him to explain the processes by which he pretended to transmute lead. The stranger at last consented, and informed him, that one grain was sufficient; but that it was necessary to envelope it in a ball of wax before throwing it on the molten metal; otherwise its extreme volatility would cause it to go off in vapour. They tried the experiment, and succeeded to their heart’s content. Helvetius repeated the experiment alone, and converted six ounces of lead into very pure gold.

The fame of this event spread all over the Hague, and all the notable persons of the town flocked to the study of Helvetius to convince themselves of the fact. Helvetius performed the experiment again, in the presence of the Prince of Orange, and several times afterwards, until he exhausted the whole of the powder he had received from the stranger, from whom, it is necessary to state, he never received another visit; nor did he ever discover his name or condition. In the following year Helvetius published his Golden Calf,¹⁹ in which he detailed the above circumstances.

About the same time, the celebrated Father Kircher published his Subterranean World, in which he called the alchymists a congregation of knaves and impostors, and their science a delusion. He admitted that he had himself been a diligent labourer in the field, and had only come to this conclusion after mature consideration and repeated fruitless experiments. All the alchymists were in arms immediately, to refute this formidable antagonist. One Solomon de Blauenstein was the first to grapple with him, and attempted to convict him of wilful misrepresentation, by recalling to his memory the transmutations by Sendivogius, before the Emperor Frederic III. and the Elector of Mayence; all performed within a recent period. Zwelfer and Glauber also entered into the dispute, and attributed the enmity of Father Kircher to spite and jealousy against adepts who had been more successful than himself.

It was also pretended that Gustavus Adolphus transmuted a quantity of quicksilver into pure gold. The learned Borrichius relates, that he saw coins which had been struck of this gold; and Lenglet du Fresnoy deposes to the same circumstance. In the Travels of Monconis the story is told in the following manner:— “A merchant of Lubeck, who carried on but little trade, but who knew how to change lead into very good gold, gave the King of Sweden a lingot which he had made, weighing, at least, one hundred pounds. The King immediately caused it to be coined into ducats; and because he knew positively that its origin was such as had been stated to him, he had his own arms graven upon the one side, and emblematical figures of Mercury and Venus on the other. ”I,“ continued Monconis, ”have one of these ducats in my possession; and was credibly informed, that, after the death of the Lubeck merchant, who had never appeared very rich, a sum of no less than one million seven hundred thousand crowns was found in his coffers.“²⁰

Such stories as these, confidently related by men high in station, tended to keep up the infatuation of the alchymists in every country of Europe. It is astonishing to see the number of works which were written upon the subject during the seventeenth century alone, and the number of clever men who sacrificed themselves to the delusion. Gabriel de Castaigne, a monk of the order of St. Francis, attracted so much notice in the reign of Louis XIII, that that monarch secured him in his household, and made him his Grand Almoner. He pretended to find the elixir of life; and Louis expected, by his means, to have enjoyed the crown for a century. Van Helmont also pretended to have once performed with success the process of transmuting quicksilver; and was, in consequence, invited by the Emperor Rudolph II. to fix his residence at the court of Vienna. Glauber, the inventor of the salts which still bear his name, and who practised as a physician at Amsterdam about the middle of the seventeenth century, established a public school in that city for the study of alchymy, and gave lectures himself upon the science. John Joachim Becher, of Spire, acquired great reputation at the same period; and was convinced that much gold might be made