At the same time even these early alchemists cannot be denied a certain scientific character, or at least a connection with natural science. Behind alchemy existed a constant experimental progress. “Alchemy,” said Berthelot, “rested upon a certain mass of practical facts that were known in antiquity and that had to do with the preparation of metals, their alloys, and that of artificial precious stones; it had there an experimental side which did not cease to progress during the entire medieval period until positive modern chemistry emerged from it.”[910] The various treatises of the Greek alchemists describe apparatus and experiments which are real but with which they associated results which were impossible and visionary. Their theories of matter seem indebted to the earlier Greek philosophers, while in the description of nature Berthelot noted a “direct and intimate” relation between them and the works of Dioscorides, Vitruvius, and Pliny.[911] CHAPTER VI PLUTARCH’S ESSAYS Themes of ensuing chapters—Life of Plutarch—Superstition in Plutarch’s _Lives_—His _Morals_ or _Essays_—Question of their authenticity—Magic in Plutarch—_Essay on Superstition_—Plutarch hospitable toward some superstitions—The oracles of Delphi and of Trophonius—Divination justified—Demons as mediators between gods and men—Demons in the moon: migration of the soul—Demons mortal: some evil—Men and demons—Relation of Plutarch’s to other conceptions of demons—The astrologer Tarrutius—_De fato_—Other bits of astrology—Cosmic mysticism—Number mysticism—Occult virtues in nature—Asbestos—_On Rivers and Mountains_—Magic herbs—Stones found in plants and fish—Virtues of other stones—Fascination—Animal sagacity and remedies—Theories and queries about nature—The Antipodes. [Sidenote: Themes of ensuing chapters.] Having noted the presence of magic in works so especially devoted to natural science as those of Pliny, Galen, and Ptolemy, we have now to illustrate the prominence both of natural science and of magic in the life and thought of the Roman Empire by a consideration of some writers of a more miscellaneous character, who should reflect for us something of the interests of the average cultured reader of that time. Of this type are Plutarch, Apuleius and Philostratus, whom we shall consider in the coming chapters in the order named, which also roughly corresponds to their chronological sequence. [Sidenote: Life of Plutarch.]