1019] 



on 



Liquid Oxygen in Warfare] 



595 



3. Metallic Heat Oonductiox. — A hunch of metal rods was 

 secured in the centre of the flask hy a non-conducting tuhe fixed 

 under the screw cap. To start the evaporation a solid rod of copper 

 or aluminium was inserted through the stopper and down the non- 

 conducting tube to make a regulated contact with the immersed 

 metal rods. This varied the influx of heat and consequent rate of 

 evaporation. The oxygen was delivered as in method 2. 



In all cases sufficient length of metal tube was added to warm the 

 gas up to ordinary temperature before issuing at the nozzle for 

 respiration. 



Method 1 is illustrated in Fis^. 1. 



jFiG. 2. 



A is a glass liquid oxygen container provided with a mercury 

 manometer M and release cock D. A glass vacuum syphon S 

 connects A to the evaporating chamber B, which is a flask half 

 filled with copper turnings. The outlet from B is a coiled copper 

 tube terminating in a screw release valve C. When the slowly 

 evaporating oxygen in A had increased the pressure to over half an 

 atmosphere, as registered by the manometer, I) was opened sufficiently 

 to prevent any further increase of pressure. On opening C, hquid 

 oxygen oscillated between A to B keeping up the necessary supply, the 



