[1652] The Great Ice-Age, and its Relations to the Antiquity of Man (1874).
[1653] Mammoth and the Flood.
[1654] “We cannot fix a date, in the historical sense, for events which happened outside history, and cannot measure the antiquity of man in terms of years.” Dawkins in No. Am. Rev., Oct., 1883, p. 338. Tylor (Early Hist. of Mankind, 197) says “Geological evidence, though capable of showing the lapse of vast periods of time, has scarcely admitted of these periods being brought into definite chronological terms.” Prestwich (On the geol. position and age of flint-implement-bearing beds, London, 1864,—from the Roy. Soc. Phil. Trans.) says: “However we extend our present chronology with respect to the first appearance of men, it is at present unsafe and premature to count by hundreds of thousands of years.” Southall (Recent Origin of Man, ch. 33) epitomizes the extreme views of the advocates of glaciation in the present temperate zone.
[1655] Cf. Louis Agassiz, Geological Sketches (1865), p. 210; 2d series (1886), p. 77.
[1656] J. Adhémer, Revolutions de la Mer, who advocates this theory, connects with it the movement of the apsides, and thinks that it is the consequent great accumulation of ice at the north pole which by its weight displaces the centre of gravity; and as the action is transferred from one pole to the other, the periodic oscillation of that centre of gravity is thus caused. The theory no doubt borrows something of its force with some minds from the great law of mutability in nature. That it is a grand field for such theorizers as Lorenzo Burge, his Preglacial Man and the Aryan Race shows; but authorities like Lyell and Sir John Herschel find no sufficient reason in it for the great ice-sheet which they contend for. Cf. H. Le Hon’s Influence des lois cosmiques sur la climatologie et la géologie (Bruxelles, 1868). W. B. Galloway’s Science and Geology in relation to the Universal Deluge (Lond., 1888) points out what he thinks the necessary effects of such changes of axis. J. D. Whitney (Climatic changes of later geological times, Mem. Mus. Comp. Zoöl., vii. 392, 394) disbelieves all these views, and contends that the most eminent astronomers and climatologists are opposed to them.
[1657] Of the manifold reasons which have been assigned for these great climatic changes (Lubbock, Prehistoric Times, 391, and Croll, Discussions, enumerates the principal reasons) there is at least some considerable credence given to the one of which James Croll has been the most prominent advocate, and which points to that reduction of the eccentricity of the earth’s orbit which in 22,000 years will be diminished from the present scale to one sixth of it, or to about half a million miles. This change in the eccentricity induces physical changes, which allow a greater or less volume of tropical water to flow north. In this way the once mild climate of Greenland is accounted for (Wallace’s Island Life). Croll first advanced his views in the Philosophical Mag., Aug., 1864; but he did not completely formulate his theory till in his Climate and time in their geological relations, a theory of secular changes of the earth’s climate (N. Y., 1875). It gained the acquiescence of Lyell and others; but a principal objector appeared in the astronomer Simon Newcomb (Amer. Jl. of Sci. and Arts, April, 1876; Jan., 1884; Philosoph. Mag., Feb., 1884). Croll answered in Remarks (London, 1884), but more fully in a further development of his views in his Discussions on Climate and Cosmology (N. Y., 1886). Whitney’s Climatic Changes argues on entirely different grounds.
[1658] Principles of Geology, ch. 10-13, where he gives a secondary place to the arguments of Croll.
[1659] Emile Cartailhac’s L’Age de pierre dans les souvenirs et superstitions populaires (Paris, 1877).
[1660] Joly, L’Homme avant les métaux, or in the English transl., Man before Metals, ch. 2. Nadaillac (Les Premiers Hommes, i. 127) reproduces Mahudel’s cuts.
[1661] Foster, Prehistoric Races, 50, notes some obscure facts which might indicate that man lived back of the glacial times, in the Miocene tertiary period. These are the discoveries associated with the names of Desnoyers and the Abbé Bourgeois, and familiar enough to geologists. They have found little credence. Cf. Lubbock’s Prehistoric Times, 410, and his Scientific Lectures, 140; Büchner’s Man, p. 31; Nadaillac’s Les Premiers Hommes, ii, 425; and L’Homme tertiaire (Paris, 1885); Peschel’s Races of Men, p. 34; Edward Clodd in Modern Review, July, 1880; Dawkins’ Address, Salford, 1877, p. 9; Joly, Man before Metals, 177. Quatrefages (Human Species, N. Y., 1879, p. 150) assents to their authenticity. Many of these look to the later tertiary (Pliocene) as the beginning of the human epoch; but Dawkins (No. Am. Rev., cxxxvii, 338; cf. his Early Man in Britain, p. 90), as well as Huxley, say that all real knowledge of man goes not back of the quaternary. Cf. further, Quatrefages, Introd. à l’étude des races humaines (Paris, 1887), p. 91; and his Nat. Hist. Man (N. Y., 1874), p. 44.