addticed hy Prof. Faraday in support o/*De la Rive's Theory. 543 



larly, the conductivity of the pile (whatever may be the me- 

 thod) is diminished. 



But wishing also to concede that those diaphragms or in- 

 terpolated metallic arcs impart to the pairs the condition that 

 M. de la Rive desires, how shall we explain the non-altera- 

 tion of the tension, when the electromotor is rendered less 

 conductive by disposing the pairs in much larger cups, by 

 which the liquid strata, through which the electric fluid must 

 pass, are more extended ? This is the first and principal ex- 

 periment which I oppose to M. de la Rive, regarding his man- 

 ner of explaining the effects of tension and of decomposition, 

 and of which he does not make mention. 



I said that this was the principal of such experiments, be- 

 cause the insertion of liquid strata of great extent between the 

 pairs occurring to me as difficult, I have applied to it again 

 with series of metallic homogeneous arcs, knowing the diffi- 

 culty which the electric current encounters in passing through 

 alternate liquid and metallic conductors. Now, I have re- 

 peated that principal experiment also on a large scale, that is, 

 with two electromotors; the one with small troughs, in which 

 the plates were so disposed, that between the copper of one 

 pair and the zinc of the next there was only a stratum of water 

 of the size of one millimeter; and the other with great re- 

 ceivers, so that the stratum of water, which divided one pair 

 from the other, was half a meter. The number of the pairs 

 being equal in both apparatus, the tension was also equal in 

 both. 



I have tried also to oblige the current to pass through many 

 cups of water connected by means of little siphons filled with 

 the same liquid ; but I did not succeed by this in obtaining in- 

 creased tension. 



Finally, in order not to vary in any way the conditions of 

 the apparatus with respect to the development of the electri- 

 city according to the electro-chemical theory, I prepared a 

 pile of three pairs, in one of which the plate of zinc commu- 

 nicated with that of copper by a small metallic wire a thou- 

 sand meters in length, and in each of the other two the wire 

 which connected the coi)per and the zinc was five hundred 

 meters in length. The apparatus was arranged so that that 

 communication could be easily taken away, and one substi- 

 tuted for it, not longer than four or five millimeters. Now, 

 when the metallic communications between the zinc and the 

 copper were formed of short wires, the deviation which the 

 pile produced in the galvanometer was twenty degrees; and 

 when the long were substituted ibr the short wires, it was only 

 fourteen ; yet the tension was always the same in both cases. 



