This physician of Montpellier, to whom chemistry is indebted for some steps in its progress, flourished at the beginning of the seventeenth century. He believed in the transmutation of metals, but is not considered as an adept, though he wrote seventeen treatises on this subject, and on the Spagiric Medicine. His most curious work is _Alchimista Christianus_. Toulouse, 1632, 8vo. In _Hercules Piochymicus_, published at the same place two years later, he maintains that the labours of Hercules are allegories, which contain the arcana of Hermetic philosophy. He defines the philosophical stone as the seed out of which gold and silver are generated. It is three and yet one; it may be found in all compounded substances, and is formed of salt, mercury, and sulphur, which, however, are not to be confounded with the vulgar substances so denominated. HELVETIUS. The following singularly impressive and even convincing testimony to the alleged fact of metallic transmutation was published by the eminent Dutch physician, John Frederick Helvetius, at the Hague in 1667, and was dedicated to his friends, Dr Retius of Amsterdam, Dr Hansius of Heidelberg, and Dr Menzelin of Brandeburg. “On the 27th December 1666, in the afternoon, a stranger, in a plain, rustic dress, came to my house at the Hague. His manner of address was honest, grave, and authoritative; his stature was low, with a long face and hair black, his chin smooth. He seemed like a native of the north of Scotland, and I guessed he was about forty-four years old. After saluting me, he requested me most respectfully to pardon his rude intrusion, but that his love of the pyrotechnic art made him visit me. Having read some of my small treatises, particularly that against the sympathetic powder of Sir Kenelm Digby, and observed therein my doubt of the Hermetic mystery, it caused him to request this interview. He asked me if I still thought there was no medicine in Nature which could cure all diseases, unless the principal parts, as the lungs, liver, &c., were perished, or the time of death were come. To which I replied, I never met with an adept, or saw such a medicine, though I read much of it, and often wished for it. Then I asked if he was a physician. He said he was a founder of brass, yet from his youth learned many rare things in chemistry, particularly of a friend--the manner to extract out of metals many medicinal arcana by the use of fire. After discoursing of experiments in metals, he asked me, Would I know the philosophers’ stone if I saw it? I answered, I would not; though I read much of it in Paracelsus, Helmont, Basil, and others, yet I dare not say I could know the philosophers’ matter. In the interim he drew from his breast pocket a neat ivory box, and out of it took three ponderous lumps of the stone, each about the size of a small walnut. They were transparent and of a pale brimstone colour, whereto some scales of the crucible adhered when this most noble substance was melted.