EFFECTS OF CALORIC ON BODIES. 407 



Providence and Mercy. Frost and snow are but 

 cheerless subjects for contemplation, yet I would add 

 a reflection in my Journal of our passing event, or 

 rather recall from memory the truth, that science 

 has made known to us, revived by the sight of that 

 frozen pool. There is one universal body, inherent 

 in every known substance in nature, latent heat, 

 which chemists have agreed to call " caloric." By 

 artificial means bodies may be deprived of certain 

 portions of it ; and then the substance most usu- 

 ally contracts, and increases in weight. Water is 

 an exception to this ; for, in losing a part of its 

 heat, the cause of its fluidity, and becoming ice, 

 it expands, and is rendered lighter, by inclosing, 

 during the operation, more or less of atmospheric 

 air : consequently it swims, covering the surface. 

 To this very simple circumstance, ice floating and 

 not sinking, are the banks and vicinities of all the 

 rivers, lakes, pools, or great bodies of water in. 

 northern Europe, Asia, and America, rendered 

 habitable, and what are now the most fertile and 

 peopled would be the most sterile and abandoned, 

 were it not for this law of nature. Had ice been 

 so heavy as to sink in water, the surface, on freez- 

 ing, would have fallen to the bottom, and a fresh 

 surface would be presented for congelation ; this 

 would then descend in its turn, and unite with the 

 other ; and thus, during a hard frost, successive 

 surfaces would be presented, and fall to the bottom, 

 as long as the frost or any fluid remained. By 

 this means the whole body of the water would 



