Sir William Drummond, the learned apologist of Egyptian science, conceives that the laws of _latent_ heat were even known to the philosophers of that ancient nation, and that caloric in such a state, was symbolically represented by VULCAN, while _free_ or _sensible_ caloric was as clearly described in the character of VESTA. Those who maintain the antiquity of chemistry, and suppose that the fabulous conceptions of the ancients were but a mysterious veil ingeniously thrown by philosophy between nature and the lower order of people, consider that the alchemical secret is metaphorically concealed in the fable of the GOLDEN FLEECE of the Argonauts, and reject the more probable solution of this story by Strabo, who says that the Iberians, near neighbours of the Colchians, used to receive the gold, brought down from the high lands by the torrents, into sieves and sheep skins, and that from thence arose the fable of the golden fleece. Dionysius, of Mytilene, offers a different explanation of the fable, and supposes it to allude to a book _written on skins_, and containing an account of the process of _making gold_ according to the art of alchemy. Notwithstanding the confidence with which modern philosophers have claimed the discovery, the experimental mode of investigation was undoubtedly known and pursued by the ancients, who appear, says _Mr. Leslie_,[95] to have concealed their notions respecting it, under the veil of allegory. _Proteus_ signified the mutable and changing forms of material objects, and the inquisitive philosopher was counselled by the Poets[96] to watch their slippery demon when slumbering on the shore, to bind him, and compel the reluctant captive to reveal his secrets. This, adds Mr. Leslie, gives a lively picture of the cautious, but intrepid advances of the skilful experimenter;—he tries to press nature into a corner,—he endeavours to separate the different principles of action,—he seeks to concentrate the predominant agent, and labours to exclude, as much as possible, every disturbing influence. But with whatever ingenuity and success the antiquity of chemical knowledge may be advocated, as it relates to the various arts of life, yet it must be allowed that not the most remote trace of its application to physic can be discovered in the medical writers of Greece or Rome. The operation of distillation[97] is not even mentioned by Hippocrates or Galen; and the waters of different plants, as described by some later authors, are to be understood, as we are informed by Gesner, merely as simple decoctions, and not as the products of any chemical process; while the Essences of Dioscorides, Galen, Oribasius, and others, were only the extracts produced by the evaporation of such infusions.