42 ON SOME CHEMICAL AGENCIES OF ELECT1UCITT. 



1 oh ' consequence; and that this is really the, case seems to be 

 the preceding shown by many tacts. Thus, in all the instances in which I 

 phenomena, examined alkaline solutions through which acids had been 

 transmitted, I always found acid in them whenever any acid 

 matter remained at the original source. In time, by the at- 

 tractive power of the positive surface, the decomposition and 

 transfer undoubtedly become complete; but this does not 

 affect the conclusion. 



In the cases of the separation of ,the constituents of water, 

 and of solutions of neutral salts forming the whole of the) 

 chain, there may possibly be a succession of decompositions 

 and recompositions throughout the fluid. And this idea is 

 strengthened by the experiments on the attempt to pass ba- 

 rytes through sulphuric acid, and muriatic acid through so- 

 lution of sulphate of silver, in which, as insoluble com- 

 pounds are formed and carried out of the sphere of the 

 electrical action, the power of transfer is destroyed. A simw 

 lar conclusion might likewise be drawn from many pther 

 instances. Magnesia and the metallic oxides, as I have 

 already mentioned, will pass along moist amianthus from the 

 positive to the negative surface; but if the vessel of pnre~ 

 water be interposed, they do not reach the negative vessel, 

 but sink to the bottom. These experiments I have very often 

 made, and the results are perfectly conclusive ; and in the 

 case, page 39, in which sulphuric acid seemed to pass in 

 small quantities through very weak solutions of strontites 

 and barytes, 1 have no doubt but that it was carried through 

 by means of a thin stratum of pure water, where the solution 

 had been decomposed at the surface by carbonic acid ; for in 

 an experiment similar to these in which the film of car- 

 bonate of barytes was often removed and the fluid agitated, 

 no particle of suLphuric acid appeared in the positive part of 

 the chain. 



It is easy to explain, from the general phenomena of de- 

 composition and transfer, the mode in which oxigen and 

 hidrogen are separately evolved from water. The oxigen 

 of a portion of water is attracted by the positive surf-ice, at 

 the same time that the other constituent part, the hidrogen, 

 is repelled by it; and the opposite process takes place at the 

 negative surface; and in the middle or neutral point of the 



circuit, 



