433 Cf. p. 254.

434 Cf. Harting, op. cit., pp. 22, 50: 〜J〙avais cru d〙abord que ces couches concentriques ûˋtaient produites par l〙alternance de la chaleur ou de la lumiû´re, pendant le jour et la nuit. Mais l〙expûˋrience, expressûˋment instituûˋe pour examiner cette question, y a rûˋpondu nûˋgativement.〝

435 Liesegang, R. E., Ueber die Schichtungen bei Diffusionen, Leipzig, 1907, and other earlier papers.

436 Cf. Taylor〙s Chemistry of Colloids, pp. 146〓148, 1915.

437 Cf. S. C. Bradford, The Liesegang Phenomenon and Concretionary Structure in Rocks, Nature, XCVII, p. 80, 1916; cf. Sci. Progress, X, p. 369, 1916.

438 Cf. Faraday, On Ice of Irregular Fusibility, Phil. Trans., 1858, p. 228; Researches in Chemistry, etc., 1859, p. 374; Tyndall, Forms of Water, p. 178, 1872; Tomlinson, C., On some effects of small Quantities of Foreign Matter on CryôÙstalôÙliôÙsaôÙtion, Phil. Mag. (5) XXXI, p. 393, 1891, and other papers.

439 A Study in CryôÙstalôÙliôÙsaôÙtion, J. of Soc. of Chem. Industry, XXV, p. 143, 1906.

440 Ueber Zonenbildung in kolloidalen Medien, Jena, 1913.

441 Verh. d. d. Zool. Gesellsch. p. 179, 1912.

442 Descent of Man, II, pp. 132〓153, 1871.