CHEMICAL REACTION IN THE INTERFEROMETER U-GA UGE By CARL BARus

We have also been able to make satisfactory glass potential measurements in humid summer weather under conditions which would have proved hopeless for the quadrant electrometer. This may be due to the fact that the electrostatic field associated with the 2.3-volt grid circuit is so small in comparison with that present in the vicinity of the electrometer vane (50 volts) that stray atmospheric charges are not so readily collected in the former case. 1 N. H. Furman, J. Am. Chem. Soc., 44, 2685, 1922; Trans. Am. Electroch. Soc., 43, 79, 1923; Van der Meulen and Wilcoxon, J. I. E. C., 15, 62, 1923; Popoff and McHenry, J. I. E. C., 20, 534, 1928; W. T. Richards, J. Phys. Chem., 32, 990, 1928; Closs and Kahlenberg, Trans. Am. Electroch. Soc., preprint, Sept. 24, 1928. 2 E. J. Roberts and F. Fenwick, J. Am. Chem. Soc., 50, 2125, 1928. 3 W. S. Hughes, (a) J. Am. Chem. Soc., 44,2860, 1922; (b) J. Chem. Soc., 1928,491; F. J. Watson, Chem. Eng. Min. Rev., 20, 59, 1927; Kerridge, Biochem. Journal, 19, 611, 1925. 4 Jones and Kaplan, J. Am. Chem. Soc., 50, 1845, 1928; C. E. Davis and G. M. Davidson, Ibid., 50, 2053, 1928; Beans and Walden, Ibid., 50, 2673, 1928. 5 (a) Goode, J. Am. Chem. Soc., 44, 26, 1922; (b) Treadwell, Helv. Chim. Acta., 8, 89, 1925; (c) Williams and Whitenack, J. Phys. Ch., 31, 519, 1927; (d) C. Morton, Trans. Faraday Soc., 24, 14, 1928; (e) E. Linde, Svensk. Kem. Tidskrift, 39, 285, 1927. 6 After most of this work had been completed (August 12th) the authors learned that H. M. Partridge has carried out similar measurements of glass cell potentials with a vacuum tube potentiometer, at New York University. I MacInnes and Parker, J. Am. Chem. Soc., 37, 1449, 1915. 8 Willard and Fenwick, Ibid., 44, 2508, 1922.