[58] Wilhemy. Pogg. Ann. cxix. pp. 121, 122.

[59] Colloidal Chemistry, p. 19.

[60] Allgemeine Chem. d. Kolloide, p. 13.

[61] Přibram, Die Bedeutung der Quellung und Entquellung für physiologische und pathologische Erscheinungen. Kolloid Chem. Beihefte, ii. p. 1.

[62] Perrin, Kolloid Chem. Beihefte, i. p. 221.

[63] A particle of gamboge in a colloidal solution has a mass 109 times that of a molecule of hydrogen.

[64] Acids in Tan Liquors, Journ. Soc. of Chem. Ind., 1910, p. 1354.

[65] Journ. Soc. Chem. Ind., 1911, p. 3.

[66] Ibid., 1911, p. 872.

[67] An improved form of hydrogen electrode devised by Dr. H. Sand may now be obtained from Universitäts-mecanikes Fritz Köhler, Leipzig. It is shown at I in Fig. [10].