PROCEEDINGS 



OF THE 



Aiwil 23, 1877. 

 Pkof. J. Clerk Maxwell, F.K..S., President, in the chair. 



A communication was made to the Society by 



Mr Arthur Schuster, Ph.D., On the passage of electricity 

 through gases. 



The spectroscope has hitherto done very little in clearing up 

 the important questions connected with the discharge of electricity 

 through gases. The reason of this must be looked for in the 

 difficulty which experimenters have found in settling the chemical 

 origin of the spectra presented by gases which have become 

 luminous through the electric discharge. It was also some time 

 before spectroscopists perceived clearly the meaning of the different 

 spectra seen sometimes in one and the same tube. The ground is 

 beginning to clear now, and I propose to shew in this paper how 

 the spectroscope may be made useful in study of the passage of 

 electricity through gases. 



Faraday has made the remark, that the differences known to 

 exist between the negative and positive pole of a discharge of 

 electricity through a gaseous medium may be due to secondary 

 chemical causes, such as produce similar phenomena in some 

 electrolytes. If this is true we should expect to find different 

 spectra at the two poles ; for the secondary chemical causes referred 

 to by Faraday consist in the formation of chemical compounds at 

 the poles, and we know that each compound has its own spectrum. 

 It has long been known that nitrogen gives a spectrum at the 

 negative pole which under ordinary circumstances is seen in no 

 Vol. in. Pt. in. 5 



