SPECTRA FROM THE WEHNELT INTERRUPTER. I. 



Ey Harry W. Morse. 



Presented by John Trowbridge, February 5, 1904. Received February 25, 1904. 



Nearly every one who has written on the suhject of the electrolytic 

 interrupter of Wehnelt has noticed and described the brilliant light 

 which is produced about the "active" electrode when the interrupter 

 is in action. Wehnelt himself * examined this light, and states that he 

 found in its spectrum lines of hydrogen, the D-lines of sodium, and, 

 when the active electrode was made negative, many other bright lines. 

 Voller and Walter | made a more complete qualitative study of the 

 spectra, and found that apparently any metal, when used as active 

 electrode in the Wehnelt arrangement, gave its characteristic spectrum. 

 They speak also of the fact that it was necessary to frequently change 

 the electrolyte, as the metal which had been used in preceding ex- 

 periments as active electrode contaminated succeeding spectra, and 

 showed its own lines together with those of the metal under examina- 

 tion. These same facts have been brought out more fully, though still 

 in a very crude and qualitative way, by Hoppe t and Werner von 

 Bolton §, both of the latter suggesting the use of the phenomenon for 

 producing colored light and spectra for demonstration. Simon || states 

 that in the form of interrupter which he used, in which the break takes 

 place, not at a metal point, but in the electrolyte at a narrow open- 

 ing in a dividing diaphragm between two large electrodes, the same 

 light-phenomena are produced, but no further data on the spectra are 

 given. Hale IT examined the spectrum of an iron point in the Wehnelt 

 interrupter in connection with other spectra produced by the arc under 

 liquids. Konen,** in a paper on the same subject, also speaks of these 



* W. A., 68, 233 (1899). || W. A., 68, 860 (1890). 



t W. A., 68, 539 (1899). . f Astropliys. J., 15, 131 (1902). 



} Klectrotecli. Ztscli., 21, 507 (1900). ** Drudcs An., 9, 742 (1902). 

 § Ztscli. f. Ek'ctroclietn., 9, 913 (Nov. 1903). 



