[141] The formation of an ammonium salt in the latter action still further reduces the concentration of the hydroxide-ion (Chapter VI) and retards the action; but the solution, in equal measure, becomes less active toward the indicator, phenolphthaleïn (p. 114). The experiment shows, therefore, rather fairly, the relative activities of the bases. The exact work of Arrhenius included consideration of the effect of the ammonium salt, and the clearing up of the mystery of this effect (p. 114) formed one of the greatest triumphs of his theory. [142] Arrhenius, ‹Electro-chemistry›, p. 184 (1902). A second accelerative factor, the so-called "salt effect" (Chap. VI, ‹q. v.›), is more pronounced in the case of 0.1 molar hydrochloric acid than in that of 0.1 molar acetic acid, as the result of which the activity of the hydrochloric acid should be increased about ten per cent; the ratio, therefore, of the speeds of reaction, both the degrees of ionization of the acids and the "salt effect" being considered, should be approximately 83 : 1, whereas the ratio found by experiment is 79 : 1. [143] ‹Vide› also A. A. Noyes, ‹Report of the Congress of Arts and Science›, Vol. «IV», p. 311 (1904). [144] Haber, ‹Z. für Elektrochem.›, «10», 775 (1904); see Chapter XII. [145] This is, essentially, the old Berzelius view of chemical action. [146] ‹Vide›, for instance, Stieglitz, ‹Report of the Congress of Arts and Sciences›, St. Louis, «IV», 276 (1904); W. A. Noyes, ‹Ibid.›, 285; Nef, ‹J. Am. Chem. Soc.›, «30», 645 (1908). For the application of the electron theory to organic compounds, see Falk and Nelson, ‹School of Mines Quarterly›, «30», 179, and ‹J. Am. Chem. Soc.›, «32», 1637 (1910). (‹Cf.› also Chapter XV.) [147] ‹J. Phys. Chem.›, «6», 1 (1902), and other papers in the same Journal. [148] ‹Cf.› Patten, ‹ibid.›, «7», 168 (1903), and Falk and Waters, ‹Am. Chem. J.›, «31», 398 (1903). According to the latter investigators, the evolution of hydrogen is slow and weak. [149] Patten, ‹loc. cit.› [150] Students will not be capable of following the argument given in the succeeding passages and would better omit this part until Chapter XV has been studied. [151] Kablukoff, Z. ‹phys. Chem.›, «4», 430 (1889). See also Nernst, ‹Theoretical Chemistry›, p. 373. [152] In view of the low order of accuracy of the data, and of the approximate method of calculation, this result is only qualitative, but even with an error of 10^2 to 10^4 the argument in the text would hold. [153] For hydrogen under atmospheric pressure, the equilibrium ratio, [Zn^{2+}] / [H^{+}]^2, is, approximately, 10^{27}. [154] ‹Vide› Sackur, ‹Z. Elektrochem.›, «11», 387 (1905). Kahlenberg holds a different view; ‹ibid›.