Gompertz does not hesitate to declare that this grand work of the ancient Atomists “is destined to survive all changes of opinion and thought.” Furthermore, all exact knowledge of nature “rests entirely on this attempt to reduce qualities to quantities, or, to speak more precisely, to establish fixed relations between the two. Mathematical physics was contained there as in a germ, and modern research took its starting-point thence. Galileo, Descartes, Huygens,--they all followed the same path. ‘I do not believe,’ declared Galileo, ‘that anything else is required than magnitudes, shapes, quantities, and slow movements or swift, to produce in us tastes, smell, sounds.’”[27] FOOTNOTES: [Footnote 23: Weber, Alfred, “History of Philosophy,” Page 139.] [Footnote 24: Weber, _Op. Cit._, Pages 136-137. Epicurus was the author of about three hundred writings, according to Diogenes Laertius, but only his Letters, preserved by this historian, and fragments of a work discovered at Herculaneum remain. For the rest we are dependent on the _resume_ presented by Lucretius and the quotations found in Greek authors. As Weber remarks (Page 135), “neither polytheism nor Christianity had any interest in preserving his numerous writings.”] [Footnote 25: Lange expressed the opinion that Epicurus really believed in the existence of the gods, reverenced them for their perfection: “these careless and painless gods did in fact represent, as it were, an incarnated ideal of his philosophy” (_Op. Cit._, Vol. I, Page 101.)] [Footnote 26: See Berman, Dr. Louis, “The Glands Regulating Personality,” New York, 1922; Cunningham, J. T., “Hormones and Heredity,” London. 1922.] [Footnote 27: Gompertz, _Op. cit._, Page 349.] CHAPTER V POST-CLASSICAL ATOMISM The two principal links in the chain which binds the world of the ancient Greek (and _one_ Roman) Atomists with those of our own times are Descartes (1596-1650) and Gassendi (1592-1655). Gassendi revived and ably supported the atomic theory of Epicurus; while Descartes resuscitated the mechanistic conceptions of the Greek Atomists on the basis of a corpuscular theory of matter, corresponding in many respects to the doctrine of Democritus. The work of Leucippus connects through Descartes and Gassendi, Huygens, Boyle and Newton, directly with that of Higgins and Dalton, founders of the modern chemical atomic theory. Dalton had already adopted a physical atomic theory, based no doubt on the work of his illustrious predecessors, and upon his own thorough study of the gases of the atmosphere, before he formulated his chemical atomic hypothesis. He opposed the prevailing belief that the various gases exist in the atmosphere in a state of chemical combination, asserting that the atmosphere is a physical mixture.