¹ I shall refer in my text to the Third English Edition of the translation of the Seventh Russian Edition by George Kamensky (2 vols.; New York, Longmans, Green and Co., 1905). The Principles first appeared in Russian in 1869. This English edition includes as appendixes three important essays, “An Attempt to Apply to Chemistry One of the Principles of Newton's Natural Philosophy,” “The Periodic Law of the Chemical Elements,” and “An Attempt toward a Chemical Conception of the Ether.”

² The words of Prince Peter Kropotkin, who attended Mendeleev's lectures in 1867–1869, quoted by Sir William A. Tilden, Famous Chemists (London: G. Routledge & Sons, Ltd., 1921), p. 245.

³ His confidence in the Periodic Table and daring in predictions based on it were typical of his whole scientific personality, especially when taken in contrast with the caution of Lothar Meyer. This is the appraisal of many historians, including Ernst von Meyer in A History of Chemistry, tr. George M'Gowan (London: Macmillan Co., 1891), p. 348; Henry M. Leicester in “Factors Which Led Mendeleev to the Periodic Law,” Chymia, ed. Tenney L. Davis (Philadelphia: University of Pennsylvania Press, 1948), Vol. I, pp. 67, 69, 72–74; and Branislav Petronievics in Slav Achievement in Advanced Science (London: The American Book Supply Co., Ltd., 1917), p. 30.

⁴ Tilden, op. cit., pp. 244, 245; Leicester, op. cit., p. 70: and Daniel Posin, Mendeleyev (New York: McGraw-Hill Book Co., Inc. 1948), p. 147.

⁵ Aristotle, Categories, Ch. 5, 2” 11–19, Basic Works of Aristotle, ed. Richard McKeon (New York: Random House, 1941), p. 9.

⁶ John Locke, Essay Concerning Human Understanding (Vol. I; Oxford: Clarendon Press, 1894), Pt. II, Ch. xxiii, Sec. 1–2, pp. 390–392.

⁷ This is stated in the paper, “An Attempt to Apply to Chemistry One of the Principles of Newton's Natural Philosophy”: “It is impossible to recognise, as constant and fundamental properties of atoms, powers which, in substance, have proved to be variable.” (II, 476) It is reminiscent of Newton's Rule III: “The qualities of bodies, which admit neither intensification or remission of degrees, and which are found to belong to all bodies within reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever.” Sir Isaac Newton's Mathematical Principles of Natural Philosophy, tr. Andrew Motte, revised by Florian Cajori (Berkeley, Cal.: Univ. of California Press, 1934), p. 398.

⁸ For example, the Periodic Law led Mendeleev to predict, among other things, the existence of “Ekasilicon” (Germanium) and many of its properties to fill a gap in the Table. (II, 27)

⁹ Leicester, op. cit., pp. 72–73, cites this as an example of Mendeleev's confidence in his systemizing: “In this respect he differed sharply from Lothar Meyer, who also saw some of the consequences of the law, but said, ‘It would be rash to change the accepted atomic weights on the basis of so uncertain a starting point.’ Meyer later remarked, ‘I willingly admit that I did not have the boldness for such further assumptions as Mendeleev later correctly proposed.’”

¹⁰ Shortly afterwards Ernst Mach was to insist, “The atomic theory plays a part in physics similar to that of certain auxiliary concepts in mathematics; it is a mathematical model for facilitating the mental reproduction of facts.” The Science of Mechanics, tr. Th. J. McCormack (La Salle, Ill.: The Open Court Publishing Co., 1942), p. 590.

¹¹ To continue our classical allusions, this conception comes much closer to Plato's Receptacle and the way we come to conceive of it than to Aristotle's lowest primary substances: “… the mother and Receptacle of what has come to be visible and otherwise sensible must not be called earth or air or fire or water, nor any of their compounds or components; but we shall not be deceived if we call it a nature invisible and characterless, all-receiving, partaking in some very puzzling way of the intelligible and very hard to apprehend … itself apprehended without the senses by a sort of bastard reasoning, and hardly an object of belief.” Timaeus, 51A-52B, in Plato's Cosmology, tr. F. M. Cornford (London: Routledge and Kegan Paul, 1937), pp. 186, 192. There is some kind of an intellectual debt here to Plato, however remote it may be, despite the aspersion in Mendeleev's Remarks on Public Instruction in Russia, as reported by Tilden, op. cit., p. 247: “We could live at the present day without a Plato, but a double number of Newtons is required to discover the secrets of nature, and to bring life into harmony with the laws of nature.” For Mendeleev's poor opinion—and poor knowledge—of the “classics,” see Benjamin Harrow, Eminent Chemists of Our Time (New Yrok: D, Van Nostrand Company, 1920), pp. 21, 37–38.

¹² This resembles Emil Meyerson's claim in 1908 that the concept of an element as literally present in any compound is only a “thing of our thought”: “For it will in no way help to affirm that, silver being a definite element, the pure substance may necessarily exist in the piece of metal which I am holding, which I call by the same name, but which I know to be impure. The existence of the silver-element is only a hypothesis which is obtained after many deductions; and pure silver, like the mathematical lever, the ideal gas, or the perfect crystal are abstractions created by a theory.” Identity and Reality, tr. Kate Loewenberg (London: George Allen & Unwin, 1930), 1930, p. 31.

¹³ For example, he imbibed a reverence for science from his mother, as indicated in his introduction to his Solutions (quoted by Tilden, op. cit., p. 243): “She instructed by example, corrected with love, and in order to devote him to science she left Siberia with him, spending thus her last resources and strength. When dying, she said, ‘Refrain from illusions, insist on work, and not on words. Patiently search divine and scientific truth.” She understood how often dialectical methods deceive, how much there is still to be learned, and how, with the aid of science, without violence, with love but firmness, all superstition, untruth, and error are removed, bringing in their stead the safety of discovered truth, freedom for further development general welfare, and inward happiness. Dmitri Mendeléeff regards as sacred a motner's dying words.” Cf. Leicester, op. cit., p. 68. One would not be tempted to be very critical of the beliefs of this sort of person, especially if one were her son.

Or again, systemizing suited his peculair genius. “Above all, he possessed the power to synthesize his facts into significance, to marshall them in order, and to recognize the relations between them. His real interest lay in the implications and philosophical relations of the facts he discovered or learned. He could never leave a fact to stand alone.” Ibid., p. 72. One is happy to assume the possibility of an activity which engages one's best talents.

¹⁴ For Boyle's use of a substance ontology, see my “Boyle's Metaphysic of Science,” this journal, Vol. XXIII (April, 1956), pp. 136–141. And for an interesting general study of the concept of substance in the history of chemistry, which perhaps inadvertently reveals how confused has been its use, see J. R. Partington, “The Concepts of Substance and Chemical Element,” Chymia. ed. Tenney L. Davis (Philadelphia: University of Pennsylvania Press, 1948), Vol. I, pp. 109–123.