4:62 Mr. H. Smith: Spectroscopic Study of the Electric 



If the secondary of an induction-coil is connected to two 

 electrodes immersed in a liquid, one electrode being a metal 

 plate and the other a wire enclosed in glass with only the 

 extreme end exposed, a luminous brush is obtained at this 

 enclosed electrode. Konen (I. c.) examined this brush in 

 various liquids and found that the nature of the pole did 

 not affect the spectrum, while the nature of the liquid was 

 all important. He examined this brush in a large number 

 of liquids and weak solutions. Distilled water gave the D 

 lines of sodium and the hydrogen lines, while weak solutions 

 gave also the strongest lines of the metal of the dissolved 

 salt. He looked for, but was unable to find, the lines of 

 oxygen. He does not mention whether he observed both 

 the spectra of hydrogen. Ether, alcohol, and glycerine 

 gave the hydrogen lines and the Swan spectrum. Glycerine 

 also gave the oxygen lines. Ammonia gave the I) lines, 

 the spectrum of hydrogen, and the ammonia bands. 



Konen's observations were limited because they were 

 visual only and because he was unable to produce a condensed 

 brush. He found that the insertion of a condenser in parallel 

 with the discharge cell destroyed the brush. 



This type of discharge seems to have received no attention 

 since Konen's account of it, and as it presents interesting- 

 features which are quite different from the arc and the 

 spark-discharge in liquids, the present research was under- 

 taken to investigate it more fully. The brush and the 

 capillary discharge, in distilled water and in a few weak 

 salt solutions have been studied. 



Apparatus. 



A large induction-coil, the primary being fed with alter- 

 nating current, was used to produce the discharge. The 

 electrodes used for producing the brush were made from 

 platinum wires of various diameters. These were sealed into 

 glass tubes ? the protruding end of each wire being filed off 

 till the platinum was quite flush with the glass. The liquid 

 cell in which the brush was produced contained one of these 

 electrodes, the second electrode being a square inch of 

 platinum foil (fig. 1). 



Another type of cell used was one in which the enclosed 

 electrode was replaced by a tube made of fused silica. The 

 part of the tube immersed in the liquid ended in a fine 

 capillary. The tube was filled with the same liquid as that 

 in which it was immersed, and either a platinum plate or a 



