Mr. Napier on the unequal Decomposition of Electrolytes. 93 



endosmose, the electricity taking the dissolved particles with 

 it to the negative electrode and producing the. phenomena of 

 endosmose. These suppositions therefore became the object 

 of an inquiry, which 1 shall now describe in detail. 



I took a piece of amalgamated zinc, measuring 2 by 1\ 

 inches, in such state of amalgamation that dilute sulphuric acid 

 had no action upon it; this was put into a mixture of sulphuric 

 acid and water in the proportion of 1 acid to 24 water, and 

 surrounded with copper, which was placed as close to the zinc 

 as would allow a free current of the solution between them, as 

 well as the escape of gas, with the view of interrupting as little 

 as possible the free action of the acid upon the zinc. This 

 was kept in action for an hour, when it was found that the zinc 

 had dissolved from it 97 grains. This I assumed as the max- 

 imum amount of chemical action which could be obtained be- 

 tween the zinc and acid of this strength, at least under the in- 

 fluence of copper. The zinc and copper being again put into 

 this liquid, but with the two metals 1 inch apart, connected by 

 a slip of copper at the surface of the liquid, in one hour there 

 was dissolved from the zinc 56'5 grains. The two metals 

 being again placed in the same position, but connected by two 

 copper electrodes of equal size placed into a solution of sul- 

 phate of copper, at the expiration of an hour there was de- 

 posited upon the negative electrode 9 grains of copper, and 

 there were dissolved from the zinc 10*7 grains. Taking an- 

 other zinc and copper and putting them into the acid con- 

 nected with the first in the manner practised for intensity, 

 there were deposited in one hour 17 grains. The zinc in cell 

 had lost 18 grains. With 4- pairs zinc and copper in acid 

 there were deposited 26 grains, and dissolved from the zinc 

 27*7 grains. With 6 pairs there were deposited 34 grains, 

 and dissolved from zinc 36 grains ; and with 9 pairs there were 

 deposited 43 grains, and dissolved from the zinc 45 grains. 

 And thus it went on increasing in quantity by the addition of 

 plates until the action of the acid and zinc came nearly to 

 the same as was assumed as a maximum, namely, 97 grains ; 

 with 30 pairs there were dissolved from zinc 101 grains, 

 with 35 pairs 99, which I consider very close to the assumed 

 quantity. 



Assuming the position which the results of these experi- 

 ments suggest, I would say, that if the chemical energy in- 

 duced between the acid and zinc under the influence of cop- 

 per be equal to 100 grains per hour, but by distance or the 

 interposition of a medium of inferior conducting power the 

 chemical action is reduced to 10 grains per hour, the remain- 

 ing tendency or disposition of the acid and zinc to unite 



