L AT E NT U R AT. 65 



have their freezing points, but the reduction of tem- 

 perature requisite has not in the case of all been at- 

 tained. Alcohol and ether, for example, have never 

 been frozen. 



146. IN FREEZING, LATENT HEAT BE- 

 what fr becomes COMES SENSIBLE HEAT. If Water, in Sllffi- 



of the latent cient quantity, be taken into an apartment 

 whose temperature is several degrees be- 

 low the freezing point, and then allowed to become 

 ice, it will be found that the freezing process has ac- 

 tually warmed the apartment several degrees. The 

 latent heat has been drawn off by the colder air of 

 the room, raising its own temperature, and leaving the 

 water in the condition of ice. 



147. CELLARS WARMED BY ICE. In ac- 



How can cel- 

 lars be warmed cordance with the principle above stated, 



tubs of water are sometimes set to freeze 

 in cellars, thereby to prevent excessive cold. And 

 even in the coldest climates a sufficient supply of wa- 

 ter might thus be made to secure an apartment against 

 extreme cold. 



148. EFFECT ON CLIMATE. The milder 

 ha% a fhe free*- climate of the vicinity of lakes which are 

 ing of water accustomed to freeze in winter, and the 



on climate ? ~ . , . 



moderation of the weather during a snow 

 storm, are accounted for on the same principle. As the 

 melting of snow retards in a certain degree the ad- 

 vance of spring by the heat it abstracts from the at- 

 mosphere, so the formation of ice tends to make the 

 advance of winter less rapid, by the heat which it 

 evolves. 



