The Elements of Qualitative Chemical Analysis, vol. 1, parts 1 and 2. / With Special Consideration of the Application of the Laws of Equilibrium and of the Modern Theories of Solution.

by Julius Stieglitz

[251] Zsigmondy, loc. cit., p. 161. A µµ is 1E−6 mm. The hydrogen molecule is considered to have a diameter of 0.1 µµ (O. E. Meyer), the alcohol molecule one of 0.5 µµ (Zsigmondy, loc. cit., plate IV, p. 157).

[252] Weimarn, Chem. Zentralblatt, 1907, II, p. 1293.

[253] Paal, Ber. d. chem. Ges., 39, 1436, 2859 (1906).

[254] Other varieties of heterogeneous colloidal mixtures are tabulated by Wo. Ostwald, loc. cit., p. 96.

[255] The "Cassius' purple" test for gold is an instance where the colloidal condition is used in analysis for a positive test. See Wo. Ostwald, loc. cit., p. 68, for other, similar applications for positive tests.

[256] Vide Wo. Ostwald's Kolloidchemie, 1909, and the references given by Noyes, loc. cit., p. 86.

[257] A general discussion of the preparation and properties of colloidal mixtures is given by A. A. Noyes, J. Am. Chem. Soc., 27, 86–104 (1905) (Stud.).

[258] Picton and Linder, J. Chem. Soc. (London), 61, 160 (1892), 67, 63 (1895), 71, 568 (1897), etc., and others. Wo. Ostwald, loc. cit., p. 240, gives a list of references.

[259] The arrangement of the experiment is described by Noyes, loc. cit., p. 98.

[260] Cf. Wo. Ostwald, loc. cit., p. 108. Billitzer has found that gelatine is positive in acid solution, negative in alkaline, Z. phys. Chem., 51, 147 (1905). The charges are, however, relatively small ones.