The manner in which Suidas accounts for this total silence of old authors with regard to Alchymy, is, that Dioclesian procured all the books of the ancient Egyptians to be burnt; and that it was in these that the great mysteries of chymistry were contained. Corringius calls this statement in question, and asks how Suidas, who lived but five hundred years before us, should know what happened eight hundred years before him? To which Borrichius answers, that he had learnt it of Eudemus, Helladius, Zosimus, Pamphilius, &c. as Suidas himself relates. Kercher asserts, that the theory of the Philosopher’s Stone, is delivered at large in the table of Hermes, and that the ancient Egyptians were not ignorant of the art, but declined to prosecute it. They did not appear to transmute gold; they had ways of separating it from all kinds of bodies, from the very mud of the Nile, and stones of all kinds: but, he adds, these secrets were never written down, or made public, but confined to the royal family, and handed down traditionally from father to son. The chief point advanced by Borrichius, and in which he seems to lay the principal stress, is, the attempt of Caligula, mentioned by Pliny, for procuring gold from Orpiment, (Hist. Nat. 1. xxxiii. c. 4.) But this, it may be observed, makes very little for that author’s pretensions; there being no transmutations, no hint of any Philosopher’s Stone, but only a little gold was extracted or separated from the mineral. The principal authors on Alchymy are, Geber, Friar Bacon, Sully, John and Isaac Hallandus, Basil Valentine, Paracelsus, Van Zuchter, and Sendirogius. ALKAHEST, OR ALCAHEST, In Chemistry, means a most pure and universal menstruum or dissolvent, with which some chemists have pretended to resolve all bodies into their first matter, and perform other extraordinary and unaccountable operations.