358 BULLETIN OF THE UNIVERSITY OP WISCONSIN. 



The dielectric constants of the last four solvents given in the 

 table have, to my knowledge, not been determined before. That 

 these solvents possess marked dissociating power the results 

 given in the table clearly show. Hence by the Nernst-Thom- 

 son rule they should have high values for their dielectric con- 

 stants. The dielectric constant of benzonitrile was measured 

 by Drude, 1 and found to be 26.0 at 21° C. Drude also meas- 

 ured the dielectric constant of benzyl cyanide, but his extensive 

 investigation does not include any of the nitriles of the aliphatic 

 series. The dielectric constant of liquid ammonia was meas- 

 ured by Goodwin and Thompson 2 who found the value 22.0 at 

 — 34° C, and by Coolidge, 3 who gives the value 16.2 at 14° C. 

 The substituted ammonias, Prof. Kahlenberg 4 finds, also yield 

 good conducting solutions. In view of the great dissociating 

 power of the nitriles and the substituted ammonias it seemed of 

 special interest to determine the dielectric constants of these 

 compounds, and at Prof. Kahlenberg's suggestion this work was 

 undertaken. The investigation also embraces a number of 

 other organic compounds containing nitrogen, and includes most 

 of the inorganic solvents in which Walden 5 made electrical con- 

 ductivity measurements. 



During the progress of his researches on non-aqueous solu- 

 tions, Prof. Kahlenberg collected a choice lot of preparations 

 which he kindly placed at my disposal. This greatly facili- 

 tated the experimental part of my work, and I desire to express 

 to him my thanks for this favor. 



Method and Apparatus. 



In measuring the dielectric constants the method devised and 

 elaborated by Drude 6 was used. It is unnecessary for me to 

 give a complete description of this method and of the details of 



1 Zeit. phys. Chem. 33, 309. (1897). 

 » Phys. Rev. 8. 38. (1899). 

 8 Wied. Ann. 69, 140. (1899;. 

 * Jour. phys. Chem. June (1901). 



6 Ber. d. Deutsch. Chem. Gesel. 32, 2852, (1899). Zeit. anorpr. Chem. 85, 209. H900). 

 8 Zeit. phys. Chem. 83; 267. (1897). See also Wied. Ann. 53,633. (1835); 58, 1;59, 

 17 (1806) ; 60, 28, 500, (1897). 



