"There is an Homogeneal Substance which lies open to the view of the Vulgar, from whence all Mineral Bodies are produced, it being their only true Matter; which by a long digestion is changed into various kinds of different perfection. There is likewise an Art, which most admire, but few believe, and he is very rare that knoweth it; whereby all imperfect and Fugitive Metals are made so Fixed as to endure the greatest force of Fire, which the Ancient Sages have called the Art of Transmutation, of Five to silver and six to perfect Gold. And wonderful it is, that of the base Metals, as Copper, Tin, Lead, or Iron, there should be made by virtue of this our Stone (in less than half an hours time) most perfect Silver and Gold, that will never change. This rare Art, whose virtue is so wonderful, many no doubt would gladly know, which yet every one of its admirers may not attain, and be enabled thereby to change imperfect Metals from a state of Corruption to Perfection; since all have not a right thereto, but only such whom God doth chuse as Heirs thereof, the rest for want of knowledge, groping as it were in the dark, may spend all their Time and Substance, as many have done to no purpose; Whence it is that the most Learned severely deride both this Art and the searchers thereof. Yet notwithstanding, know that this Art is most certainly true, whose Principles are Founded on Nature: Yea though its revilers are many, and but few are found that dare defend it, yet shall this Science remain immovable against all its opposers." — The Marrow of Alchemy By Eirenaeus Philoponos Philalethes c. 1654