The preceding observations will give the reader some notion of the nature of the pursuits which occupied the alchymists: their sole object was the preparation of a substance to which they gave the name of the philosopher’s stone, which possessed the double property of converting the baser metals into gold, and of curing all diseases, and of preserving human life to an indefinite extent. The experiments of Wilson, and the formula of Musitanus, which have been just inserted, will give the reader some notion of the way in which they attempted to manufacture this most precious substance. Being quite ignorant of the properties of bodies, and of their action on each other, their processes were guided by no scientific analogies, and one part of the labour not unfrequently counteracted another; it would be a waste of time, therefore, to attempt to analyze their numerous processes, even though such an attempt could be attended with success. But in most cases, from the unintelligible terms in which their books are written, it is impossible to divine the nature of the processes by which they endeavoured to manufacture the philosopher’s stone, or the nature of the substances which they obtained.[21] [21] Kircher, in his Mundus Subterraneus, has an article on the philosopher’s stone, in which he examines the processes of the alchymists, points out their absurdity, and proves by irrefragable arguments that no such substance had ever been obtained. Those who are curious about alchymistical processes may consult that work.