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THE ROYAL SOCIETY OF CANADA 



the natural ionisation was again measured with each of the gases 

 and then the ionisation when the gases were traversed by the gamma 

 rays from the source just mentioned. 



In all these experiments care was taken to dry and filter all the 

 gases thoroughly before passing them into the ionisation chamber. 



JTTL 



Fig 6. 



Fig. 7. 



The hydrogen was prepared by allowing dilute sulphuric acid to act 

 on granulated zinc in a Kipp apparatus. The carbon dioxide was taken 

 from a cylinder of the product usually sold commercially. The nitrous 

 oxide was also taken from a cylinder of the gas prepared commercially 

 for the use of anaesthetists. The ethylene used was prepared by gently 

 heating in a flask a quantity of pure white anhydrous phosphorus 

 pentoxide to which a small quantity of absolute alcohol had been added 

 and the acetylene was prepared in the usual way by allowing water to 

 act on calcium carbide. 



