[127] Gore, ‹Proc. Royal Soc.›, «14», 204 (1841). Gore found that aluminium was dissolved and that sodium and potassium were attacked by the gas, even before its liquefaction. It is uncertain whether these positive reactions are reactions of absolutely anhydrous hydrogen chloride or the result of the presence of moisture in the experiments in question, since Cohen [‹Chem. News›, «54», 305 (1896)], drying the gas more carefully than did Gore, found, in contrast to the latter, that metallic sodium may be exposed for several weeks to dry hydrogen chloride gas and retain its lustre. In all experiments demanding the rigorous exclusion of moisture, more weight must be attached to negative results (showing lack of activity) than to positive results. [‹Cf.› the controversy between Baker, ‹loc. cit.›, and Gutmann, ‹Liebig's Ann.›, «299», 3 (1898)]. [128] Nernst's ‹Theoretical Chemistry›, p. 375. Kablukoff, ‹Z. phys. Chem.›, «4», 430 (1889). [129] In regard to the behavior of zinc, see below, p. 84. (‹Cf.› Kahlenberg, ‹J. Phys. Chem.›, «6», 13 (1902) (‹Stud.›).) [130] For a fuller discussion of the benzene solution see p. 84. [131] The ‹acid› character, in particular, is due to the hydrogen-ion, H^{+}; see below. [132] The fusion is conveniently made in a platinum dish; the dish and a platinum cathode are connected with the lighting circuit and an electric lamp. [133] See Smith, ‹Inorganic Chemistry›, pp. 550, 569, 578, 588, 608, 610, 683: ‹College Chemistry›, 361, 373, 380, 389, 404, 405, 443 («Stud.»). [134] ‹J. Chem. Soc.› (Abstracts) (London), «40», 504 (1881). [135] For positive evidence of the ionizing power of light, see Haber, ‹Z. Elektrochem.›, «11», 847 (1905). For evidence as to the negligible rôle of ionization in the combination of chlorine and hydrogen, see Mellor, ‹Chemical Statics and Dynamics› (1904), p. 290. [136] The apparatus described by A. A. Noyes and Blanchard for comparing acids is used [‹J. Am. Chem. Soc.›, «22», 737 (1900)]. [137] The conductivity depends in this case chiefly on the migration of the ‹fast moving hydroxide ions› (p. 56), common to the three bases. There is little difference in the rates at which the cations move. [138] The water should be free from carbonic acid.