[199] See below, in regard to evidence that the disturbing factors, predominant with strong electrolytes, are exhibited in much slighter, but perceptible measure in the case of the weak electrolytes. [200] See also the interpretation of the law of chemical equilibrium from the viewpoint of the kinetic theory, Nernst, ‹Theoretical Chemistry›, p. 428. [201] For a more detailed discussion of these views, see Lehfeldt's ‹Electrochemistry› (1904), pp. 78, 79. [202] Various empirical laws, expressing the behavior of strong electrolytes, have been suggested: see Nernst, ‹Theoretical Chemistry›, p. 498, as to Rudolphi's and van 't Hoff's rules; see also A. A. Noyes, ‹Report of the Congress of Arts and Science›, «IV», p. 316 (1904). [203] Wegscheider, ‹Z. phys. Chem.›, «70» (I), 603 (1909). [204] It is possible that this effect is only another form of expressing the very relation discussed in the preceding paragraph. [205] Arrhenius, ‹Z. Elektrochem.›, «6», 10 (1899); ‹Z. phys. Chem.›, «31», 197 (1899). [206] Salts have constants averaging about 7, and running from 5 to 28; the constant for ice is about 3. Landolt, Börstein, Meyerhoffer, ‹Tabellen›, p. 766 (1905). [207] We have: Ice, 3, water (at 0°), 80; glacial acetic acid, 2.8, acetic acid (liquid), 10; cane sugar, 4, cane sugar in aqueous solution (40%), 67.5, (6.5%), 45.3. ‹Ibid.› [208] ‹Z. phys. Chem.›, «23», 280 (1897). [209] ‹Wiedemann's Ann.›, «60», 625 (1897). [210] See Walden, ‹Z. phys. Chem.›, «61», 636 (1908), in regard to the difficulties of the problem. [211] ‹Loc. cit.› [212] ‹Cf.› Szyszkowski, ‹Z. phys. Chem.›, «58», 420 (1907). [213] Arrhenius made a calculation of the effect, taking into account all the rather involved changes produced by the salt. ‹Loc. cit.› [214] For instance, the principle of "isohydric solutions," discovered by Arrhenius, has been established empirically and it involves relations which are in marked disagreement with the demands of the law of chemical equilibrium. ‹Vide› A. A. Noyes, ‹Report of the Congress of Arts and Sciences›, «IV», p. 318 (1904). [215] The most reliable estimates of the concentrations of ions in these solutions are based on determinations of the degrees of ionization by means of conductivity measurements (see Chap. IV, and the previous footnote). [216] Salts MeX ionize more readily (80–85% in 0.1 molar solution) than do salts Me″X_{2} or Me_{2}X″ (50 to 70% in 0.1 molar solution), and these, again, more readily than salts Me″X″ (about 40% in 0.1 molar solution).