28 An Account of some Experiments 



Exp. 5. It gave a vivid spark, after being in action three 

 hours. At the expiration of twenty- four hours, it retained 

 sufficient power to metaUize ammonia, and continued, with 

 gradually decreasing energy, to produce the same effect till 

 the end of forty-one hours, when it seemed nearly exhausted. 

 From the results of the foregoing experiments, which, 

 though simple and not numerous, I trust, are satisfactory, 

 we see Mr. Davy's theory of the mode of action of the Vol- 

 taic battery confirmed : he says (in his Paper on some Che- 

 mical Agencies of Electricity, Sect. 9, after having shown 

 the effect of induction to increase the electricity of the op- 

 posite plates), " the intensity increases with the numher.^ 

 and the quantity with the extent of the series." 



That this is so, the effects produced on the platina and 

 iron wires, in the first and fifth experiments with the large 

 battery, and the subsequent experiments on imperfect con- 

 ductors, with the small apparatus, sufficiently prove. The 

 platina wire being a perfect conductor, and not liable to be 

 • oxidated, presents no obstacle to tlie free passage of the 

 electricities through it, which, from the immense quantities 

 given out from so large a surface, evolve, on their mutual 

 annihilation, heat sufficient to raise the temperature of the 

 platina to the point of fusion. 



With the iron wire, of y^th of an in«h diameter, the 

 effect is very different, which is explained by the low state 

 of the intensity of the electricity (sufficiently proved by its 

 not causing any divergence of the gold leaves of the electro- 

 meter), which being opposed in its passage by the thin coat 

 of oxide, formed on the iron wire, at the moment the cir- 

 cuit is completed, a very small portion only of it is trans- 

 mitted through the wire. To the same want of intensity is 

 to be attributed the total inability of the large battery to de- 

 compose the barytes^ and its general weak action on bodies 

 which are not perfect conductors. The fmall battery, on the 

 contrary, exerts great power on imperfect conductors, de- 

 composing them readily, although its whole surface is more 

 than thirty times le^s than that of the great battery ; but in 

 point of number of plates, it consists of nearly ten times as 

 many as the large one. The long continued action of the 



small 



