114 CONTRACTION AND EXPANSION 



from each other, and its elasticity increased at the 

 expense of the hydrogen. Nay more, it is by virtue 

 of this very attraction that the atoms of hydrogen 

 are forced into chemical union with those of chlo- 

 rine, and their separate individuality destroyed. In 

 other words, all the above changes, including that 

 by which the gases are united and identified, are 

 referable wholly to the transition of caloric from 

 the one to the other. 



It will be shown hereafter, that no chemical 

 combination of any one body with another ever 

 takes place, without a simultaneous passage of 

 caloric or electricity from one to the other; that if 

 water and other liquids could exist as such without 

 caloric, (which is impossible,) they could not com- 

 bine with salts, metals, and rocks ; and that the 

 diminution of bulk which attends the combination 

 of liquids with solids, is owing to the same law 

 which determines the reduction of volume and 

 elastic force of gases and vapours. The most 

 simple illustration of combination effected by the 

 attraction of ponderable matter for caloric, is that 

 by which steam is condensed by water or ice, and 

 intimately combined with their particles. When 

 a certain proportion of steam is mixed with cold 

 water, its volume and elastic force are destroyed 

 by the same attraction of ponderable matter for 

 caloric which causes liquids to combine with, and 

 dissolve solids, or which causes gases to combine 

 chemically, with contraction of volume and dimi- 

 nution of elastic force. 



