DECOMPOSITION BY CONTACT, 195 



be accounted for in no way but by ascribing it to the higher 

 affinity of sulphuric acid for soda, than that of boracic acid for 

 the same base. 



According to the same views, on mixing together two 

 neutral salts containing different acids and bases, and which 

 do not precipitate each other, each acid should combine with 

 both bases, so as to occasion the formation of four salts. 

 Again, four salts, of which the acids and bases are all 

 dissimilar, should react upon each other in such a way as to 

 produce sixteen salts, each acid acquiring a portion of the four 

 bases ; and certain acids and bases, dissolved together in certain 

 proportions, could have but one arrangement in which they 

 would remain in equilibrio. Hence the salts in a mineral water 

 would be ascertained by determining the acids and bases pre- 

 sent, and supposing all the bases proportionally divided among 

 the acids. But this conclusion is inconsistent with a fact 

 observed in the preparation of factitious mineral waters, name- 

 ly, that their taste depends not only on the nature of the salts, 

 but also upon the order in which they are added, (Dr. Struve 

 of Dresden.) Before we can determine how the acids and 

 bases are arranged in a mineral water, or what salts it contains, 

 it may therefore be necessary to know the history of its forma- 

 tion. Instead of supposing the bases equally distributed among 

 the acids in mixed saline solutions, it is now more generally 

 assumed that the strongest base may be exclusively in possession 

 of the strongest acid, and the weaker bases be united with the 

 weaker acids, a mode of viewing their composition which agrees 

 best with the medical qualities of mineral waters. It thus 

 appears that the doctrines of Berthollet, by which the result- 

 ing actions between bodies in contact are made to depend upon 

 their relative quantities or masses and the physical properties of 

 the products of their combination, to the entire exclusion of the 

 agency of proper affinities between the bodies in contact, 

 cannot be admitted as a true representation of the actual 

 phenomena of combination. 



CATALYSIS, OR DECOMPOSITION BY CONTACT. 



An interesting class of decompositions has of late attracted 

 considerable attention, which, as they cannot be accounted for 

 on the ordinary laws of chemical affinity, have been referred 

 by Berzelius to a new power, or rather new form of the force 



o 2 



