ELECTRO-CHEMISTRY. 1 9 



ponderable constituent of the acid. The ponderable 

 constituent of the alkali has a greater affinity for its 

 imponderable element than it has for the acid base 

 that passes through it. There is therefore no che- 

 mical change upon the solution of ammonia in the 

 cup I. When, however, the acid base of the sul- 

 phate of potash reaches the cup P, it there combines 

 with positive electricity, and has its acid properties 

 restored. If the solution in P, which is now a solu- 

 tion of sulphuric acid, be decanted into I, the positive 

 electricity of the acid will unite with the negative 

 electricity of the alkali, heat being the product ; and 

 the residual constituents of acid and alkali will now 

 combine and form a neutral salt, namely, the sulphate 

 of ammonia. 



21. When a solution of the nitrate of potash is 

 placed in the cup P, distilled water in N, and sul- 

 phuric acid in I, the nitrate of potash is decomposed, 

 and the alkaline constituent of the salt is drawn 

 through the cup I without undergoing any change 

 itself, or causing any change in the acid. What is 

 the reason of this ? 



The alkaline constituent of the salt when it enters 

 the cup I, containing sulphuric acid, does not com- 

 bine with that acid. The sulphuric acid requires to 

 be disunited from its positive electricity before it can 



