Aug. 3, 1888.J 



SCIENTIFIC NEWS. 



101 



air is easily reduced to many degrees below freezing 

 point, and is blown into the chambers in which the meat 

 is placed. One advantage of this system is that the 

 whole of the air in the chamber is reduced to the cold 

 temperature, and while it surrounds and passes over the 



after it has been compressed, will load it with moisture. 

 Compressed air, however, will not hold so much vapour 

 as at ordinary pressure, and, when it is compressed, the 

 water becomes a cloud of mist or fog. When it expands 

 this fog is absorbed again. When the spray of cold water 



meat in a continuous current, it ensures a thorough 

 chilling, and complete ventilation as well. One great 

 difficulty, however, is that any moisture in the air is 

 thrown down as a shower of snow. This is liable to ob- 

 struct the air-passages, and boys have to be sent through 

 them to clear it away. Even if the atmosphere be com- 

 paratively dry, the spray of water used to cool the air 



is injected, it makes most ot the fog settle, in fact it 

 washes it out of the air, and leaves only as much vapour 

 as it can hold at that pressure, so that we have the 

 curious paradox that it is possible to dry air by wetting it. 

 If we take instead of air, some gas or vapour which 

 when compressed, can be liquefied, we can make use of 

 the latent] heat of liquefaction, which disappears when 



