Therefore, when Van Helmont tells us that, “though a homogeneal part of elementary earth may be artfully (artificially) converted into water,” though he still denies “that the same can be done by nature alone; for no natural agent is able to transmute one element into another,” offering as a reason that the elements always remain the same, we must believe him, if not quite an ignoramus, at least an unprogressed disciple of the mouldy “old Greek philosophy.” Living and dying in blissful ignorance of the future sixty-three _substances_, what could either he or his old master, Paracelsus, achieve? Nothing, of course, but _metaphysical_ and crazy speculations, clothed in a meaningless jargon common to all mediæval and ancient alchemists. Nevertheless, in comparing notes, we find in the latest of all works upon modern chemistry, the following: “The study of chemistry has revealed a remarkable class of substances, from no one of which a second substance has ever been produced by any chemical process which weighs less than the original substance ... by no chemical process whatever can we obtain from iron a substance weighing less than the metal used in its production. In a word, we can _extract_ from iron nothing but iron.”[318] Moreover, it appears, according to Professor Cooke, that “_seventy-five years ago_ men did not know there was any difference” between elementary and compound substances, for in old times alchemists _had never conceived_ “that _weight is the measure of material_, and that, as thus measured, no material is ever lost; but, on the contrary, they imagined that in such experiments[319] as these the substances involved underwent a _mysterious transformation_.... Centuries,” in {191} short, “were wasted in vain attempts to transform the baser metals into gold.” Is Professor Cooke, so eminent in modern chemistry, equally proficient in the knowledge of what the alchemists did or did not know? Is he quite sure that he understands the meaning of the alchemical diction? We are not. But let us compare his views as above expressed with but sentences written in plain and good, albeit old English, from the translations of Van Helmont and Paracelsus. We learn from their own admissions that the alkahest induces the following changes: