\S§ Mr Ritchie's examinatvon of the electric 



feet was produced. Having removed the acid, I substituted 

 water containing condensed chlorine : a very decided electro- 

 magnetic effect was produced. A similar effect was produced 

 by using nitro-muriatic acid, or aqua regia as it was formerly 

 called, instead of the chlorine. The needle of the galvano- 

 meter in both cases turned round in the same direction as it 

 does when zinc was substituted for the gold leaf and copper 

 for the platina. Having tried, by the common method, the 

 conducting powers of the diluted sulphuric acid and the water 

 containing chlorine, I found that the diluted acid was the most 

 powerful conductor. When the preceding experiment was re- 

 peated with discs of zinc and copper instead of discs of gold 

 and platina, I found that the most powerful effect was pro- 

 duced when the diluted sulphuric acid was used. This ex- 

 periment clearly proves that the interposed fluid does not act 

 merely as a conductor to the electricity excited by the imagi- 

 nary electro-motive force, since in the first case the electricity 

 generated is greatest when the conducting power of the fluid 

 is least. 



Exp. II. — Having made a small rectangular box divided 

 into two equal compartments by a diaphragm of bladder, I in- 

 troduced into one of them a disc of hard copper, and into the 

 other an equal disc of soft copper. These discs being con- 

 nected with the cups of the galvanometer, and the chambers 

 filled with water, a considerable galvanic effect was produced, 

 and the needle turned round as it does when the place of the 

 hard copper was supplied with a disc of zinc. I then poured 

 a little nitrous acid into the chamber containing the hard cop- 

 per, and observed that the effect was diminished. By adding 

 a little more acid the needle turned round several degrees in 

 the opposite direction. This experiment completely over- 

 throws the assumed principle that the galvanic effect increases 

 with the conducting power of the fluid interposed between the 

 metallic plates, since by increasing the conducting power of 

 the fluid the effect was diminished, and by a proper increase 

 was completely destroyed. It is a curious fact, that if nitric, 

 sulphuric, or muriatic acid be used instead of the nitrous, the 

 results will be quite the reverse. 



Having thus, I trust, satisfactorily shown that the electric 



