﻿the Electric Discharge in Liquid Oxygen, Air, Sfc. 239 



vessel. We can assign no cause for this, unless it were an 

 explosion of ozone. 



Liquid Air. 



The effects of a discharge through liquid air were very 

 similar to those produced with liquid oxygen, so long as the 

 pressure was that of the atmosphere, and no jar was in circuit. 

 There was the same continuous spectrum. When a jar was 

 used a much larger number of lines, generally resembling the 

 ordinar}' air-lines, were seen but not measured. When the 

 pressure was reduced, the usual banded spectrum of nitrogen 

 was seen, and was strong relatively to the spectrum of oxygen. 

 As the liquid evaporated, and thereby lost more nitrogen than 

 oxygen, the two green bands due to oxygen appeared to be- 

 come stronger actually as well as relatively to the nitrogen 

 bands. 



In this case the discharge produced oxides of nitrogen, 

 which were detected in the residual gas when the air had all 

 evaporated. 



Liquid Nitrogen. 



We next tried liquid nitrogen. At the pressure of the 

 atmosphere, both electrodes in the liquid, and no jar, the 

 spectrum was continuous with three bright lines in the green 

 and yellowish-green, generally resembling the three lines seen 

 in liquid oxygen. On taking measures of their wave-lengths 

 it was found that they were platinum lines, the same as had 

 been seen in oxygen at wave-lengths about 505, 530, and 547. 

 The oxygen line at 533 was not seen. Besides these three 

 lines, a faint very diffuse line was observed at about \ 501, 

 and glimpses of blue bands of the usual banded spectrum of 

 nitrogen. When only one electrode was immersed in the 

 liquid, the line at about \ 501 was more distinct. We have 

 no doubt that this represents the strong double line of nitrogen 

 in that position. When the jar was in the circuit, the spec- 

 trum was a series of bright lines similar to those given by 

 gaseous nitrogen at atmospheric pressure. 



When the gas above the liquid was pumped out until the 

 pressure fell to about 1 centim. of mercury, one or both elec- 

 trodes being immersed, and no jar used, the band-spectrum 

 of nitrogen appeared. On putting on the jar this was re- 

 placed mainly by the line-spectrum. 



Spectrum of the Spark in Water. 



For the sake of comparison we next observed the spectrum 

 of the spark between platinum electrodes in distilled water at 

 the ordinary temperature and pressure. When no jar was 



