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THE ROYAL SOCIETY OF CANADA 



research was to investigate the absolute amount of hehum absorbed 

 by a given amount of charcoal and how the amount absorbed depended 

 on the quantity of helium put into the apparatus. Different quanti- 

 ties of helium were admitted into the apparatus, left for half an hour, 

 and then all the gas not absorbed was pumped out; that is the equil- 

 ibrium pressure was practically zero. 



Figure 1 



A diagram of the apparatus is shown in Fig. I. The charcoal 

 (30 grams) is contained in the tube X, which may be shut off from 

 the rest of the apparatus by means of the stop-cock C. Before each 

 experiment, this tube was heated in an electrical resistance furnace to 

 a temperature of 440° C and, while it was hot, the apparatus was 

 exhausted. The charcoal tube Z was immersed in liquid air and used 

 to complete the exhaustion. It could be shut off from the rest of the 

 apparatus at B. The discharge tube H was used to test the vacuum. 



A measured amount of gas was introduced at the Traver's siphon 

 T or through the tube N. Its pressure was read on the McLeod 

 gauge M or the barometer tube L. The stop-cock C was then opened 

 and the gas allowed to remain in contact with the cold charcoal for at 

 least thirty minutes. The unadsorbed gas was then pumped out and 



