454 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



987. Of the two modes in which bodies can transmit the electric forces, namely, 

 that which is so characteristically exhibited by the metals, and that in which it is 

 accompanied by decomposition, the first appears common to all bodies, although it 

 occurs with almost infinite degrees of difference ; the second is at present distinctive 

 of the electrolytes. It is, however, just possible that it may hereafter be extended to 

 the metals ; for their power of conducting without decomposition may, perhaps justly, 

 be ascribed to their requiring a very high electrolytic intensity for their decompo- 

 sition. 



987^. The establishment of a certain electrolytic intensity being necessary before 

 decomposition can be effected, is of great importance in all those considerations 

 which arise regarding the probable effects of weak currents, such for instance as 

 those produced by natural thermo-electricity, or natural voltaic arrangements. For 

 to produce an effect of decomposition or of combination, a current must not only 

 exist, but have a certain intensity before it can overcome the quiescent affinities 

 opposed to it, otherwise it will be conducted, producing no permanent effects. 

 On the other hand, the principles are also now evident by which an opposing 

 action can be so weakened by the juxtaposition of bodies not having quite affinity 

 enough to cause direct action between them (913.), that a very weak current shall 

 be able to raise the sum of actions sufficiently high, and cause chemical changes to 

 occur. 



988. In concluding this division (m the intensity necessary for electrolyzation, I can- 

 not resist pointing out the following remarkable conclusion in relation to intensity 

 generally. It would appear that when a voltaic current is produced, having a certain 

 intensity, dependent upon the strength of the chemical affinities by which that cur- 

 rent is excited (916.), it can decompose a particular electrolyte without relation to 

 the quantity of electricity passed, the intensity deciding whether the electrolyte shall 

 give way or not. If that conclusion be confirmed, then we may arrange circum- 

 stances so that the same quantity of electricity may pass in the same time, in at the 

 same surface, into the same decomposing body in the same state, and yet differ in in- 

 tensity, decomposing in one case and in the other not. For taking a source of too low 

 an intensity to decompose, and ascertaining the quantity passed in a given time, it 

 is easy to take another source having a sufficient intensity, and reducing the quantity 

 of electricity from it by the intervention of bad conductors to the same proportion 

 as the former current, and then all the conditions will be fulfilled to produce the re- 

 sult described. 



^ iii. On associated Voltaic circles, or the Voltaic battery. 



989. Passing from the consideration of single circles (875. &c.) to their association 

 in the voltaic battery, it is a very evident consequence, that if matters are so arranged 

 that two sets of affinities, in place of being opposed to each other as in figg. 1, 4. (880. 

 891.), are made to act in conformity, then, instead of either interfering with the 



