Chemical Science- 171 



From what precedes, the solution of the following interesting 

 question may be deduced. Two soluble substances being taken, 

 sufficient conductors of electricity to exert on each other electro- 

 motive actions, to ascertain whether when the solutions are put 

 together they form a mere mixture or a combination. In the first 

 case the solid substances by contact would lake the same electricity" 

 as their respective solutions would do when connected by amian- 

 thus; but the opposite states would be induced if there were che- 

 mical action. As examples of mere mixture, citric acid and 

 muriate of ammonia, and citric acid and chloride of sodium may be 

 quoted : the solid substances act similarly to the solutions, and 

 thus offer further proofs of the difference existing between chemical 

 combination and mechanical contact. 



This difference between the electrical effects of contact and those 

 of chemical action, indicate that there should be an intermediate 

 state in which there is no development of electricity. In another 

 memoir the means will be given of determining, as accurately as 

 possible, this passage of one electric state to another in two 

 substances, which, at first in contact without chemical action, end 

 by combining together. 



2. On the Dktribiition of Electricifij in the Voltaic Pile. By M. 

 Becquerr-l. — When a plate of zinc is immersed into diluted sulphuric 

 acid, or any alkaline solution contained in a copper vessel, without 

 contact of the metals, the vessel becomes positive and the zinc 

 negative*. This result shews that the important fact, discovered 

 by Volta, namely, that when a pile is formed entirely of metal 

 the tension of the two extreme metals is the same as if they were 

 in contact, is not applicable to the case where an acid or alkaline 

 liquid is interposed between the two metals; for according to it, 

 the zinc should be positive and the copper negative, whilst really 

 the contrary is the case. 



Represent the electric states of copper and zinc, when the two 

 metals are separated by an acid solution by + ^ and — J, and 

 the quantities of electricity, which they take by contact, by 



~ — -f — ; put a disc of copper on the zinc : this, besides its 



electricity, — _£_ '"or instance, which it will take from the zinc, 



2 

 will divide its electricity — I, which it previously possessed ; 

 and, further, the liquid as a conducting body, will transmit to the 



first disc of copper, the electricity -f- — of the zinc, so that the 

 electricities will be — 



♦ Quarleiiy Journal, xvii. 375. 



