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Mr Varley, On the Absorption of 



On the Absorption of Ultra-violet Light in different Oases. 

 By W. Mansergh Varley, B.A., Emmanuel College. 



[Received 6 June 1904.] 



The experiments described below on the absorption of ultra- 

 violet light in various gases were carried out as a preliminary 

 research to one on the photo-electric discharge from a metallic 

 surface in different more or less complex gases. 



Hitherto the only experiments published giving the absolute 

 value of the coefficient of absorption of ultra-violet light in any 

 gases appear to be those of Kreusler* who experimented with 

 air, carbon dioxide, oxygen, nitrogen and nitrous oxide. Up fco 

 a wave-length of 200 /mji he could detect no absorption in any 

 of these gases except nitrous oxide which absorbed all light below 

 300 /jl/jl. His results were unsatisfactory owing, to the irregular 

 character of the source of light employed. Schumann f and 



Fig. 1. 



others have made experiments on absorption bands, using the 

 photographic method, and hence obtaining no value for the 

 amount of absorption of the light as a whole in any part of 



* Kreusler, Ann. der Physik, Vol. vi. p. 412, 1901. 



+ Schumann, Sitz. Ber. der Kais. Akad. Wien, Vol. cm. pp. 415, 625, 1893. 



