and the Theory of Electrolysis. 95 



. One pair ....... 9*1 grs. 



Two pairs 6*8 ... 



Four pairs 5*7 ... 



Six pairs # 9 ... 



I now took a strong solution of cyanide of potassium and 

 divided it into three equal parts : into two were placed porous 

 vessels filled with sulphate of copper, in which were put the 

 negative electrode of the battery, one connected with 9 pairs of 

 small plates, the other with 1 pair of large plates. The same 

 sort of electrodes were used in both experiments. The third 

 portion of cyanide of potassium solution had a piece of copper 

 placed in it of the same size with the electrodes. The bat- 

 tery current was continued one hour. The results were — 



9 pairs deposited 12 grains, dissolved 15 grains; equivalent 

 8 grains. 



1 pair deposited 4 grains, dissolved 7 grains ; equivalent 

 24 grains. 



Piece of metal in cyanide potassium lost 1*2 grain. 



Similar experiments were made with various electrolytes 

 in the positive division, using sulphate of copper in all cases 

 in the negative, the amount deposited being taken as the mea- 

 sure of the decomposing current. 



1st. Positive cell charged with a weak solution of cyanide 

 of potassium. 



1 pair deposited 7 grains, dissolved 10 grains; equivalent 

 proportion 13'7 grains. 



9 pairs deposited 26 grains, dissolved 31 grains; equiva- 

 lent proportion 6*1 grains. 



2nd. Muriatic acid 1 to 24 water in positive solution. 



1 pair deposited 15 grains, dissolved 23 grains; equivalent 

 17 grains. 



9 pairs deposited 54 grains, dissolved 69 grains ; equiva- 

 lent 8*8 grains. 



3rd. Positive solution, nitric acid 1 to 24 water. 



1 pair deposited 17 grains, dissolved 20 grains ; equivalent 

 56 grains. 



9 pairs deposited 26 grains, dissolved 29 grains ; equiva- 

 lent 3"7 grains. 



4th. Positive solution, sulphuric acid 1 to 24 water. 



1 pair deposited 20 grains, dissolved 23 grains ; equivalent 

 4*3 grains. 



9 pairs deposited 49 grains, dissolved 55 grains ; equiva- 

 lent 3'9 grains. 



The next series of experiments are of the same kind, using 



