1919] 



on Liquid Oxygen in Warfare 



eoo 



vapour of almost identical composition. This method is therefore 

 of more advantage when almost new liquid air has to be employed 

 without much concentration of the oxygen. 



The rate of loss of liquid air is best determined by periodical 

 weighings of the containers, but a rapid estimate can be made by 

 connecting them to a yW^'i cubic foot o-as meter (or its equivalent) to 

 measure the rate of evaporation. This meter can be appropriately 

 scaled so as to indicate directly the weight loss. The factor em- 

 ployed is deduced from the curves just given, and varies by ± 5 per 

 cent, with the composition of the liquid (as indicated by the boiling 

 point). Fig. 1:^ shows how the loss per hour or per day, as required, 



116" 



lOS 



I06r_ 



WEIGHT LOSS of LIQUID AIR, 



MEASURED DIRECTLY BY 



EVAPORATION RATE; 



~ Variation with Boiling Point. 



PERIOD 



IN WHICH 



.C.C^ EVAPORATED 

 EQUALS 

 CRAMS PER DAY 



BotUNC . 



_ 49' 



PERIOD 

 IN WHICH ^ 

 ( cc^ EVAPORATED ) 



EQUALS 



CRAMS PER HOUR- 



48" 



47* 



46* 



_45" 



44r 



Q2* 



S4*Abs: eS" 66' 



Fig. 13. 



is directly deduced from the measure of the volume evaporated in 

 a stated number of seconds, and how this period varies with the 

 temperature of the liquid air. 



METAL STOEAGE VESSELS. 



The handling of liquid air and oxygen, apart from laboratory 

 use, is only practicable with metal vacuum containers ; and it is the 

 absorptive power of cooled charcoal which enables the necessary high 

 vacuum to be maintained, and thus makes it possible to construct 

 such vessels. The first vessels to give satisfaction were described in 



2 T 1^ 



