112 On some Chemical Agencies of Electricity. 



In the cases of the separation of the constituents of vvatef, 

 and of solutions of neutral sails 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 jiass ba- 

 rytes through sulphuric acid, and muriatic acid through so^ 

 lution of sulphate of silver, in which, as insoluble compounds 

 are formed and carried out of the sphere of the electrical 

 action, the power of transfer is destroyed. A similar con- 

 clusion might like\visc be drawn from many other instances. 

 Magnesia and the metallic oxides, as I have already men- 

 tioned, will pass along moist amianthus from the positive 

 to the negative surface; but if a vessel of pure water be in- 

 terposed, 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, 

 pat^e 109, in which sulphuric acid seemed to pass in small 

 quantities through very weak solutions of strontitcs and ba- 

 rvtes, 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 ui whicli the film of car- 

 bonate of barvtes 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 phsenomena of de- 

 coiTlposition and transfer, the mode in which oxygen and 

 hydrogen are separately evolved from water. The oxygen 

 of a portion of water is attracted by the positive surface, at 

 the ?ame time that the other constituent part, the hydrogen, 

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

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

 circuit, whether there be a scries of decompositions and re- 

 compositions, or whether the particles from the extreme 

 points only are active, there must be a new combination of 

 the repelled matter : and the case is analf)gous to that of 

 two portions of muriate of soda separated by distilled water j 

 muriatJc acid is repelled from the negative side, and soda 

 from the positive side, and muriate of soda is composed in 

 the middle vessel. 



These 



