no 



THE ROYAL SOCIETY OF CANADA 



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Figure 1 



then turned off and liquid air applied to G. The mercury in H rises 

 nearly to barometer height. E is then filled with gas and on opening 

 T the unit volume passes into G, where a portion condenses. When the 

 water reaches the top of E, T is turned off and E refilled from B. As 

 each unit passes into G, the pressure on the manometer is observed. 

 In the usual process of helium analysis this filling and refilling is 

 repeated from five to ten times until the gauge H may be down nearly 

 to atmospheric pressure. The tap at P is now turned and the non- 

 condensable gases sent on through the rest of the apparatus. That 

 part, however, does not concern us at present. If the non-condensable 

 gases are pumped out through P and the apparatus allowed to stand 



