Chap, i .] Expanfiou of Water in the State cf Ice. 3 97 



or latent (late. By heating them much above their 

 point of fluidity,- he 'found that they loft their heat 

 very loon, till fome parts became folid; after this they 

 continued of exactly the fame temperature till'tpe whole, 

 became folid, though expofed all the while to cold 

 air; but when all became iblid they cooled as they did 

 at firft. In the fame manner water mixed with ice, 

 whatever may be the temperature of the furrounding 

 medium, and whether the quantity of ice is increafing 

 or diminiihing, always nearly preferves the tempera- 

 ture of 3 2 degrees. 



The freezing of water was formerly attributed to 

 the entrance of frigorific particles into that fluid; but 

 * the above doctrine, founded on the great difcoveries 

 of Dr, Black, is almoft univerfally deemed fo fatisfac- 

 tory as to have left the other, which is a mere hypo- 

 thcfis, fcarcely a fmgle advocate. The augmentation 

 of the bulk of water in freezing feems to be the only 

 fact which can with reafon be alleged in fupport of 

 the doctrine of frigorific particles j but thib increafe of 

 bulk is not attended with any increafe of weight, and 

 may be much better explained, than by attributing it 

 to the addition of frigorific particles, which were never 

 proved to have any exiftence. 



The increafe which water acquires in becoming 

 iblid is about one-ninth or one-tenth of its whole bulk. 

 Boyle took a brafs tube, three inches in diameter, and 

 put forne water' into it ; he then brought down .into 

 the tube a plug with a weight placed at the head of it 

 of feventy-four pounds, On exposing the tube to the 

 cold, the water freezing and expanding itfelf, raifed 

 the feventy-four pounds. [I he expanfive power of 

 water, in the procels of freezing, was proved by a 

 remarkable experiment made in Canada. An iron 

 fhell, aftet having its mouth well plugged up, was 



filled 



