Alchemy is generally understood to have been that art whose end was the transmutation of the so-called base metals into gold by means of an ill-defined something called the Philosopher’s Stone; but even from a purely physical standpoint, this is a somewhat superficial view. Alchemy was both a philosophy and an experimental science, and the transmutation of the metals was its end only in that this would give the final proof of the alchemistic hypotheses; in other words, Alchemy, considered from the physical standpoint, was the attempt to demonstrate experimentally on the material plane the validity of a certain philosophical view of the Cosmos. We see the genuine scientific spirit in the saying of one of the alchemists: “Would to God . . . all men might become adepts in our Art — for then gold, the great idol of mankind, would lose its value, and we should prize it only for its scientific teaching.”1 Unfortunately, however, not many alchemists came up to this ideal; and for the majority of them, Alchemy did mean merely the possibility of making gold cheaply and gaining untold wealth.