CONSTITUTION OF SALTS. UJj 



bility of oxide of zinc in the acid, to which its influence 

 is generally ascribed,, accounts for the continuance of the action, 

 by providing for the removal of the oxide, rather than for its 

 first commencement. The phenomena of the decomposition 

 of an acid solution by electricity, are also most simply ex- 

 plained on the binary theory. Oxide of hydrogen and sul- 

 phatoxide of hydrogen, are both binary ' electrolytes/ which 

 are decomposed by the electric current in the same manner, 

 although not with equal facility, the common element, hydro- 

 gen, proceeding from both to the negative electrode, and the 

 oxygen in the one case and the sulphatoxygen in the other to 

 the positive electrode. The sulphatoxygen finds water there, 

 and resolves itself into sulphatoxide of hydrogen and free 

 oxygen. The decomposition of the sulphatoxide of sodium or 

 any other salt may be explained in the same simple manner ; 

 while on the other view, it must be assumed that a simulta- 

 neous transference between the electrodes of acid and alkali 

 with the oxygen and hydrogen of water takes place ; and the 

 effect of the acid in promoting the decomposition of the water 

 remains unaccounted for. 



When a metallic oxide is dissolved in an acid solution, as 

 oxide of zinc in diluted sulphuric acid, the reaction which 

 occurs is thus explained on the binary theory : 

 Sulphatoxide f Hydrogen . . -~, Water, 



of hydrogen. 1 Sulphatoxygen . ,,<' 

 Oxide of f Oxygen . *X\^ 

 zinc. \Zinc . . /___\jSulphatoxide of zinc; 



as in the reaction between the same oxide and hydrochloric 

 acid (page 160). 



The chief objections to the binary theory of salts, are 

 First: The creation of so many hypothetical radicals ; namely, 

 one for every class of oxygen-acid salts. But it is to be re- 

 membered that the great proportion of oxygen acids, such as 

 nitric, acetic, oxalic, &c. are equally of an ideal character 

 and cannot be exhibited in a separate state. 



Secondly : The peculiarities of the salts of phosphoric acid 

 are supposed to be inimical to the new view. That acid forms 

 three different and independent classes of salts, containing 

 respectively one, two and three atoms of base to one of acid. 

 On the binary theory, these three classes of salts must contain 

 three different radicals, combined respectively with one, two 



