LOW-TEMPERATURE RESEARCHES 



permanent, so long as the low temperature is main- 

 tained. Thus it is that substances which attack one 

 another eagerly at ordinary temperatures will lie side 

 by side, utterly inert, at the temperature of liquid 

 air. 



Under certain conditions, however, most interesting 

 chemical experiments have been made in which the 

 liquefied gases, particularly oxygen, are utilized. Thus 

 Olzewski found that a bit of wood lighted and thrust 

 into liquid oxygen burns as it would in gaseous oxy- 

 gen, and a red-hot iron wire thrust into the liquid 

 burns and spreads sparks of iron. But more novel still 

 was Dewar's experiment of inserting a small jet of 

 ignited hydrogen into the vessel of liquid oxygen ; for 

 the jet continued to burn, forming water, of course, 

 which was carried away as snow. The idea of a gas- 

 jet burning within a liquid, and having snow for smoke, 

 is not the least anomalous of the many strange concep- 

 tions that the low-temperature work has made familiar. 



PRACTICAL RESULTS AND ANTICIPATIONS 



Such are some of the strictly scientific results of 

 the low - temperature work. But there are other re- 

 sults of a more directly practical kind neither more 

 important nor more interesting on that account, to be 

 sure, but more directly appealing to the generality of 

 the non-scientific public. Of these applications, the 

 most patent and the first to be made available was the 

 one forecast by Davy from the very first namely, the 

 use of liquefied gases in the refrigeration of foods. 

 Long before the more resistant gases had been liquefied, 

 the more manageable ones, such as ammonia and sul- 



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