Zeitsch. physikal. C h e m . , 1904, 48, 97) , but the amount dissolved * It should be mentioned that Geffcken (Zeitsch. physikal. Chwn., 1904, 49, 257) has pointed out sources of error in the experiments of Gordon, Roth, and Rraun, which may invalidate the apparent support they afford to Jahn's empirical formula.