NOMOS. 



49 



The laws of 

 chemical affi- 

 nity are 

 never sus- 

 pended in the 

 current. 



vanic circuit, and other laws introduced in 

 their stead. There is, indeed, a well- 

 known experiment in which an alkali, in 

 apparent violation of these laws, appears 

 to traverse an acid without combining 

 with it, but where, in reality, the alkali traverses the 

 acid by combining with it on the way. In this ex- 

 periment three cups, placed side by side, are put in 

 connexion by pieces of lamp cotton soaked in solu- 

 tion of sulphate of potass. 



Fig. 13. 



The cups A and c are filled with a solution of sul- 

 phate of potass; the cup B with dilute sulphuric 

 acid ; the positive electrode of a galvanic battery, p, 

 is then dipped in A, the negative electrode, N, into 

 C, and the preliminary arrangements are complete. 

 In ordinary language, a positive current now enters 

 at P and escapes at N, traversing the three cups on 

 its way ; and the result is, that the sulphate of soda 

 in the two end cups, A and c, is decomposed, and 

 that free alkali is found in c, and free acid in A; 

 while the sulphuric acid in the central cup does not 

 appear to be affected in the least. In other words, 

 some of the liberated alkali would seem to have left 

 the cup A, and gone through the acid in the central 



