420 Troivbridge — Spectra of Gases. 



Art. XLII. — Spectra of Gases at High Temperatures; by 

 John Trowbridge. 



[Presented at the International Electrical Congress of St. Louis, 1904.] 



The new theories in regard to the complexity of the atom, 

 together with a multiplicity of ionization phenomena, make 

 the results of spectrum analysis obtained by the discharges of 

 electricity in glass or quartz tubes difficult of interpretation. 

 To use ordinary language, " so many things can happen," such 

 as dissociation ; combination wit'h the gases set free from the 

 walls of the containing tubes ; masking of the spectrum of one 

 gas by that of another, reversals of spectrum lines and so on. 



These complicated conditions which accompany our study of 

 gaseous spectra make it almost impossible to conclude from 

 laboratory experiments that we have imitated the phenomena 

 presented by the distant stars. 



For several years I have been endeavoring to obtain new 

 series of hydrogen lines which might presumably manifest 

 themselves at very high temperatures. In the progress of this 

 work I have obtained a number of interesting facts which I 

 shall dwell upon in a brief manner in this paper ; but I have 

 failed to find a new series of hydrogen lines, possibly from the 

 reason that the reactions both in glass and quartz vessels mask 

 the series. It seems impossible to experiment at a higher tem- 

 perature than I have obtained, certainly if one employs such 

 vessels as I have mentioned. 



My investigations have been conducted with a storage battery 

 of 20,000 cells, which were used to charge large condensers. 

 The advantages in using a storage battery for experiments in 

 spectrum analysis are well recognized. These advantages are 

 especially seen in the employment of condenser discharges. 

 "When the condensers are charged through a large liquid resist- 

 ance they charge to the same potential each time, and then 

 discharge without the intervention of a discharger, through 

 the Geissler tube. The number of discharges can be closely 

 regulated by the amount of liquid resistance which connects 

 the poles of the condensers to the battery. The regularity of 

 such discharges through the Geissler tubes is remarkable. In 

 popular language one can call the arrangement an electric 

 clock, for the discharges follow each other at regular intervals. 

 In this way one avoids the spark at a discharger and is sure of 

 always obtaining the same difference of potential at the ends 

 of the Geissler tube. 



The highest temperature to which one can submit a gas is 

 presumably that of the electric discharge from a condenser ; 

 opinions differ in regard to the degree of heat which one can 



