516 Mr Varley, On the Absorption of Ultra-violet Light, etc. 



Summary of Results. 



The values of a, the coefficient of absorption, calculated from 



the formula I — I e~ at , where y is the ratio of the intensity of .the 



transmitted light to that of the light which has not passed through 

 the absorbing medium, and t= the thickness of the medium traversed, 



are given below. The values of - are also given, this being the 



thickness of the medium required to reduce the intensity of the 



light to - of its original values. The values of the coefficients 



are all calculated for the gases at atmospheric pressure. 



In conclusion I must express my best thanks to Prof. J. J. 

 Thomson, in whose laboratory the experiments were carried out. 

 for his ever ready suggestions and advice. 



