FREEZING OF ALCOHOL. \J $ 



more or less of his method, were communicated to his friends, invention", an- 



it is to be regretted that he has not described it in this notice • n0l,nccQ \ .^ nt 

 i- i 11 i i ii- - • notd-jsciiueJ. 



which would, at least, have secured him against the preten- 

 sions of those who, from conjecture or otherwise, might per- 

 form the same. Without departing from the respect clue to 

 an inventor, I consider it to be quite allowable for me to make 

 a few remarks in this place, for the gratification of such of my 

 readers as may not be familiar with the general subject. 



If we except the direct cooling process, by communication Except by 



with bodies at a lower temperature, and the few instances, if' Jlcre . comn »-i- 



nu\iti:m, and 

 any, wherein cold can be said to be produced by chemical perhaps coin- 

 union, without change as to the state of aggregation, we can f) ination,there 

 i . i * . -i r . ,. ajra M0 cooling 



look to no other means oi depressing the temperature of bodies, processes 



within our knowledge, but such as may be founded upon their k"own, but 



. v r \ ii r ■ i what arise 



augmentation ot capacity for heat, when they pass from the f r om fusion or 



solid to the fluid, or from the fluid to the gaseous, state. In pacification. 

 the first of these two methods, certain bodies, such as snow fuzing mix^ 

 and salt,- one at least being in the solid state, are mixed and tare, 

 combine ; and if the combination be not congealable at (or its 

 freezing point be lower than) the heat of the surrounding or 

 neighbouring bodies, the compound will be fluid, and will take 

 from those bodies all that heat which its increased capacity as 

 a fluid demands, for the maintenance, of that state ; and con- 

 sequently those bodies will be cooled, — and one limit of this 

 process will be at the freezing point of the compound, b*low 

 which it cannot go ; though from the heat of the surrounding 

 bodies, it may be prevented from arriving at that point. 



But many of the freezing mixtures, at present known, seem which in prac- 

 to have their point of congelation far beneath any temperature SCJUVC lv be !;• 

 we can practically look toj and, therefore, a very considerable iftited, but by 

 part of the process of cooling by means of them has been jj* 1^.° " 

 directed to the prevention of the efFect of foreign heat, by first 

 cooling the ingiedients, and surrounding the vessels with other 

 cooling materials. Whether these precautions have been as 

 much varied and applied, as the circumstances appear to de- 

 mand, may, with justice, be doubted. 



In the second method, by the evaporation of a fluid, such as The- second 



water in various economical processes, and alcohol and ether metlj< * d ! s b 7 



.ti-ii evaporation; 



in philosophical experiments, the rapidity with which the ga- 

 seous state is assumed, under like circumstances, governs the 



result ) 



