during the combination of hydrogen and chlorine? 91 



that the first effect of exposing the mixed gases to light is a 

 considerable increase in volume without any production of HC1, 

 then after an interval which depends on the intensity of the 

 light the formation of HC1 begins, and when once started 

 persists. 



The conductivity of the mixed gases was tested in both these 

 stages, the gases being exposed to diffuse and not very bright 

 daylight ; many experiments were made but in no case was any 

 increase observed in that small rate of leak which exists in these 

 as well as in other gases, even when not exposed to light. It 

 thus appears that both during the combination of hydrogen and 

 chlorine as well as in the preliminary stage marked by an increase 

 in volume there are no free charged ions. 



In the next place an experiment was tried to see whether the 

 artificial production of free charged ions in the mixed gases would 

 affect their rate of combination. In this experiment the mixed 

 gases were exposed to Rontgen rays which produced free ions in 

 such numbers that the leaves of the electroscope collapsed in 

 a few seconds, but no effect could be detected either in promoting 

 combination when the gases were kept in the dark or in altering 

 the rate of leak when the gases were exposed to diffuse daylight. 

 The radiation from thorium was also tried, but it was without 

 effect. 



