Two Fluids, and of Two Metals not in Contact. 539 



instance from the comparison of the iron circuits with %inc and 

 tin circuits; but why both alkalies with the iron circuits, and 

 the ammonia with tin circuits have in general a iveaker action 

 than water, — why, even with the combinations zinc-platina, 

 zinc-silver, the alkahes have the ascendency over the water, is 

 according to that view not conceivable. 



It is the same in all those cases in which two oxy-combinations 

 are opposed to one another : water and carbonate of soda, sul- 

 phuric acid and borax, sulphate of zinc and borax, sulphate of 

 magnesia and borax. 



Perhaps here, from the carbonate of soda and borax being 

 easily decomposable salts, and their solutions in the cases ex- 

 amined always succumbing to that of the second oxy-combina- 

 tion, a position from the Experimental Researches might be 

 brought forward (§ 549) according to which substances are said 

 to produce a more powerful current the more difficultly decom- 

 posable they are, and vice versa. Thus might also be explained 

 the general weaker action of dilute acids in comparison to 

 water, since acidulated water is more easily decomposable than 

 pure. However, this position appears hardly in unison with 

 the fundamental principle of the chemical theory, that the affi- 

 nity of the oxygen, chlorine, &c., for the zinc, is that which ex- 

 cites the cm'rent ; for it might rather be supposed that this affi- 

 nity can the less enter into activity the more stronglj^ the oxy- 

 gen, chlorine, &c., are retained by the positive element from 

 which they are to be separated. Moreover, it cannot be applied 

 to the alkahes, which in most cases increase the electromotive 

 force and yet at the same time render water more decomposable 

 than it is of itself. A further example, among many others, is 

 affi^rded by salt and sal-ammoniac, two chlorides, the solution 

 of the latter of which developes a stronger electromotive force 

 than that of the first. It can hardly be admitted that sal- 

 ammoniac is of more difficult decomposition than salt ! 



The solution of chlorine likewise, if I correctly understand 

 Faraday's view, could not, according to it, act differently from 

 pure water; for the chlorine is merely dissolved in the water, 

 not combined with a body to form an electrolyte. Nevertheless 

 it acts with zinc-platina, for instance, much more strongly than 

 water. It acts, moreover, instantaneously on immersion, so that 

 the action can scarcely proceed from formed chloride of zinc, 

 which is also evident from the fact, that solution of chlorine, 

 which has been frequently employed, containing therefore a 

 .considerable quantity of chloride of zinc, does not act in the 

 least more powerfully than when pure. 



If, on the other hand, the action is derived from the chlorine, 

 then again, according to this view, it cannot be conceived why 



20^ 



