Peculiar Voltaic Arrangements. 137 



Having of late made some researches with the view of dis- 

 covering the true cause of the polar state which the electrodes 

 acquire within electrolytic fluids during the passage of a cur- 

 rent, 1 was led to observe a striking analogy between metallic 

 peroxides on one side, and chlorine and bromine on the other, 

 with regard to the electromotive pov/er of those substances, all 

 of them being highly what is called electro- neg;!tive. First let 

 us consider the way in which the two substances last men- 

 tioned give rise to currents. If an open glass tube being tied 

 up at one of its extremities with a piece of bladder and holding 

 an aqueous solution either of chlorine or bromine be put 

 within a tumbler filled with water, and both fluids connected 

 by the means of platina-wires with a delicate galvanometer, a 

 continuous current makes its appearance, the direction of 

 which is such, as to indicate that the fluid holding chlorine 

 dissolved, is to pure water what copper is to zinc. How is 

 this current excited ? Does it perhaps originate in some action 

 exerted by chlorine upon platina ? I do not know whether a 

 weak solution of chlorine has at common temperatures the 

 power to act chemically upon that metal ; I strongly doubt it : 

 but let us suppose such to be the case, it appears to me that 

 the current in question cannot be accounted for in the manner 

 alluded to. If the current was due to some chemical action 

 of chlorine upon platina, its direction ought, according to the 

 theoretical views of some distinguished electricians, (to De la 

 Rive and Becquerel's for instance) to be the vei*y opposite to 

 that which is really observed, the chemical union of chlorine 

 with any metal being in a voltaic point of view considered by 

 them as equivalent to the oxidation of metallic bodies. But it 

 is much less the direction of the current in question which 

 makes me think that it (the current) cannot be excited in con- 

 sequence of the formation of some chloride of platina, than the 

 fact that any current should be called forth under the circum- 

 stances mentioned. Agreeably to my views, and I think they will 

 coincide with those of Faraday, no current at all would be 

 excited within the arrangement spoken of if no electrolytic body 

 were decomposed there, though chlorine should happen to act 

 ever so powerfully upon platina; but if the current in question 

 is not due to any action of chlorine upon the metal mentioned, 

 we may ask, what is the chemical cause that disturbs the 

 electrical equilibrium within our arrangements ? Though I am 

 not aware that chemists allow chlorine or bromine to decom- 

 pose water in any sensible degree without being assisted by the 

 agency of light or heat, I am nevertheless prepared to think 

 that such an action takes place, and that it is this which 

 must be considered as the chemical cause of the current 



