MOLECULAR COMBINATION. 277 



earth, produced by solar influence, may modify those 

 changes, is probable. It is, however,, certain that wo 

 must regard all manifestations of chemical force as 

 dependent upon some secret principles common to all 

 matter, diffused throughout the universe, but modified 

 by the influences of the known imponderable elements, 

 and by the mechanical force of aggregative attraction. 



Bodies undergo remarkable changes of form, and 

 present very different characters, by reactions,, which 

 are of several kinds. We suppose that a permanent 

 corpuscular arrangement is maintained so long as the 

 equilibrium of the molecular forces is undisturbed. 

 Water, for instance, remains unchanged so long as the 

 balance of affinity is kept up between the oxygen and 

 hydrogen of which it is composed, or so long as the 

 oscillations of force between these combining elements 

 are equal; but disturb this force, or set up a new 

 vibratory action, as by passing an electric current 

 through the water, or by presenting another body, which 

 has the power of reacting upon one of these corpuscular 

 systems, and the water is decomposed, the hydrogen and 

 oxygen gases being set free, or one alone is liberated, 

 and the other combined with the molecules of the agent 

 employed, and a new compound produced. This is 

 chemistry, by which science we discover all the com- 

 binations of matter. 



Having reason to conclude that atom combines with 

 atom, according to a system most harmoniously arranged, 

 there can be no difficulty in conceiving that molecule 

 unites with molecule, in a manner regulated by some 

 equally well-marked law. It was, indeed, a discovery 

 by Wenzel, of Fribourg, that, in salts which decompose 

 each other, the acid which saturates one base will also 

 saturate the other base ; and the subsequent observations 

 of Eichter, of Berlin, who attached proportional num- 

 bers to the acids and bases, and who remarked that the 

 neutrality of metallic salts does not change during the 



