CALORIC. 271 



the Wind ; and the robin puffing out his feathers, and 

 contracting his neck into his body, is peeping with his 

 fine "bright eyes into the windows from the cypress 

 bough. A few evergreens are waving their sprays, and 

 glittering in the light, yet making but poor compensa- 

 tion for the variety, the flutter, the verdure, of our sum- 

 mer. Though we have little natural beauty to note or 

 to record, we are not left without a testimony of an 

 overruling Power ; and, however sad and melancholy 

 things may appear at the first view, yet a more steady 

 observation will manifest to ug a presiding Providence 

 and Mercy. Frost and snow are but cheerless subjects 

 for contemplation, yet I would add a reflection in my 

 Journal of our passing events, 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 

 usually 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 opera- 

 tion, more or less of atmospheric air: consequently it 

 swims, covering the surface. To this very simple cir- 

 cumstance, 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 freezing 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 re- 

 mained. By this means the whole body of the water 

 would become a dense concretion of ice : its inhabitants 

 would not only perish, but the indurated mass would 



* See note LL, appendix. 



