CHAPTER VI.
ALCHEMY AS AN EXPERIMENTAL ART.
A modern writer, Mr A.E.Waite, in his _Lives of the Alchemystical Philosophers_, says: "The physical theory of transmutation is based on the composite character of the metals, on their generation in the bowels of the earth, and on the existence in nature of a pure and penetrating matter which applied to any substance exalts and perfects it after its own kind." It must he admitted that the alchemists could cite many instances of transmutations which seemed to lead to the conclusion, that there is no difference of kind between the metals and other substances such as water, acids, oils, resins, and wood.

We are able to-day to effect a vast number of transformations wherein one substance is exchanged for another, or made to take the place of another.

We can give fairly satisfactory descriptions of these changes; and, by comparing them one with another, we are able to express their essential features in general terms which can be applied to each particular instance.

The alchemists had no searching knowledge of what may be called the mechanism of such changes; they gave an explanation of them which we must call incorrect, in the present state of our knowledge.

But, as Hoefer says in his _Histoire de la Chimie_, "to jeer at [the alchemical] theory is to commit at once an anachronism and an injustice....