﻿768 Dr. E. B. Ludlam on the Action of 



effect observed might not be due to a chemical action between 

 the chlorine and the carbon bisulphide under the influence of 

 the light. 



Curve V. 



4 10 100 fairs , 



Condenser Potential 

 Influence of greater per cent, of chlorine on ions produced in air. 



If this were the case, the presence of a large excess of 

 chlorine would result in the absorption of the light by the 

 chlorine without production of ions before the photo-chemical 

 action could come into play. 



Wave-length. — Throughout each series of experiments 

 observations were made upon the wave-length of the light- 

 producing the various effects, and similar results were 

 always obtained, of which the table below is characteristic. 



Air at the rate of 2*4 litres per minute, chlorine I'D per 

 cent., trace of carbon bisulphide. 



Medium between Spark Deflexion 



and Gas. + — 



3 cm. air, J mm. quartz 100 100 



,, ., 3 mm. gypsum (fine split 



crystal plate) 81 77 



3 cm. air, 3 mm. gypsum (old and 



rubbed) 10 10 



3 cm. air, calc-spar 2* 8 



3 cm. ultra-violet crown glass 4 4 



Violet crown glass 2 



Ordinary glass 



* This is an unusually low value, 8 is nearer the average, although the 

 positive deflexion was usually rather less than the negative when calc- 

 spar was used. 



