Consistent Direction of the Evolved and combifiing Bodies, 179 



dec?)mposition, it will be necessary, not merely to observe cer- 

 tain effects dependent upon a current of electricity, but also 

 their quantity, and though it may often happen that the forces 

 concerned in any particular case of chemical action may be 

 partly exerted in one mode and partly in the other, it is only 

 those which are efficient in producing the current that have 

 any relation to voltaic action. Thus, in the combination of 

 oxygen and hydrogen to produce water, electric powers to 

 a most enormous amount are for the time active (861. 873.) ; 

 but any mode of examining the flame which they form during 

 energetic combination, which has as yet been devised, has 

 given but the feeblest traces. These therefore may not, can- 

 not, be taken as evidences of the nature of the action; but are 

 merely incidental results, incomparably small in relation to 

 the forces concerned, and supplying no information of the 

 way in which the particles are active on each other, or in 

 which their forces are finally arranged. 



961. That such cases of chemical action produce no cur- 

 rent of electricity^ is perfectly consistent with what we know 

 of the voltaic apparatus, in which it is essential that one of the 

 combining elements shall form part of, or be in direct relation 

 with, an electrolytic conductor (921. 923.). That such cases 

 produce no free electricity of tension^ and that when they are 

 converted into cases of voltaic action they produce a current 

 in which the opposite forces are so equal as to neutralize each 

 other, prove the equality of the forces in the opposed acting 

 particles of matter, and therefore the equality of electric power 

 in those quantities of matter which are called electro-chemical 

 equivalents (824.). Hence another proof of the definite na- 

 ture of electro-chemical action (783. &c.), and that chemical 

 affinity and electricity are forms of the same power (917. &c.). 



962. The direct reference of the effects produced by the 

 voltaic pile at the place of experimental decomposition to the 

 chemical affinities active at the place of excitation (891.917.), 

 gives a very simple and natural view of the cause why the 

 bodies or ions evolved pass in certain directions ; for it is only 

 when they pass in those directions that their forces can con- 

 sist with and compensate (in direction at least) the superior 

 forces which are dominant at the place where the action of 

 the whole is determined. If, for instance, in a voltaic circuit, 

 the activity of which is determined by the attraction of zinc 

 for the oxygen of water, the zinc move from right to left, 

 then any other cation included in the circuit, being part of an 

 electrolyte, or forming part of it at the moment, will also 

 move from right to left; and as the oxygen of the water, by 



2 A 2 



