146 Dr. Fyfe on the Use of Sulphate of Copper 



employed. In a voltaic circuit the forces which make the in- 

 strument active are of two kinds, the one local, the other that 

 which is transmitted along the object by which the communi- 

 cation is established. Of course it is of the utmost conse- 

 quence in all voltaic arrangements, to have as much as possible 

 of the latter made to circulate, because it is by means of it 

 that electrolytic action is effected. By using the trough re- 

 commended in the paper alluded to, Mr. Faraday found, that 

 for the same destruction of zinc, the electrolytic action, in 

 other words the quantity of electricity transmitted through the 

 electrolyte, was greater than when a trough of ordinary con- 

 struction was used. In the trough mentioned, which by 

 Faraday is considered superior to the best previously in use, 

 viz. that with double coppers, in which the cells are insulated, 

 there was, even when acting under favourable circumstances, 

 a considerable waste of electricity. In a perfect trough this 

 would not be the case, but as in all arrangements now in use 

 it has been found to be so, owing to the interfering powers, 

 which prevent the transference of electricity from one end to 

 the other, it is desirable to discover means by which it may 

 be prevented, so that if possible there should be no waste 

 of the electrolytic agent, provided at the same time we can 

 do so by means equally ceconomical with those commonly re- 

 sorted to; and I trust that the experiments now to be stated 

 will show that this is, to a certain extent, within our reach. 



The trough generally employed in the following experiments 

 consisted of thirty copper and zinc plates, on the principle of 

 the couronne des tasses; the copper three inches square, the zinc 

 three inches long and one and a half wide. It was capable 

 of holding sixty ounces of fluid. The measure of the quantity 

 of electricity conveyed through the electrolyte was of course 

 that pointed out by Faraday ; using in all the experiments 

 solution of sulphate of soda, always of the same strength, in 

 the volta-electrometer, and electrodes of the same size. The 

 experiments were occasionally varied by sometimes collecting 

 both gases, and sometimes only one : 25 degrees of the volta- 

 electrometer were equal to one cubic inch. 



Oil of Vitriol. — When diluted oil of vitriol is used, the loss 

 of electricity is considerable, and depends much on its state 

 of dilution. 163*3 grains by weight, when mixed with sixty 

 ounces of water, discharged 14 measures of hydrogen in the 

 volta-electrometer. 490 grs., that is, three times as much, 

 diluted with the same quantity of water as above, discharged 

 very nearly three times as much gas; but when 1470 grs. 

 were used, I did not find that the amount of decomposition 



