280 M. De la Rive's Researches 



current, in consequence of the difference in the quantities of 

 electricity developed by the two unequal chemical actions. 



But, it will be said, if such be the fact, how is it that a 

 stronger tension is not obtained by putting an oxidable metal 

 in communication with the electroscope and then immersing 

 it by its extremity in an acid solution instead of holding it in 

 the fingers ? How is it that the strongest electric currents are 

 not always produced by the most lively chemical actions, and 

 that a metal immersed in a liquid which attacks it but feebly, 

 forming a pair with another metal, or a piece of the same me- 

 tal immersed in a liquid which acts upon it strongly, can be 

 sometimes positive, that is to say, that whence the current 

 commences ? To explain these anomalies and reconcile them 

 with the chemical theory, recourse must be had to a principle 

 which indeed flows from the nature of things, viz. the imme- 

 diate recomposition in a larger or smaller proportion of the two 

 electricities developed by chemical action. It is necessary then 

 carefully to distinguish the electricity perceived from the elec- 

 tricity produced ; the latter must evidently be proportional 

 to the extent of the chemical action, that is, that in a given 

 time it depends upon the number of chemical atoms which 

 are combined, and consequently upon all the other circum- 

 stances which may have exerted an influence upon the num- 

 ber of these combinations (the extent of the surface exposed 

 to chemical action, the vivacity of that action, &c). The elec- 

 tricity perceived is a proportion of the electricity produced, a 

 proportion which depends upon the relative conductibility of 

 the bodies entering into the system in which the electricity is 

 propagated, upon the disposition of the different parts of the 

 system and upon the nature of the apparatus to be employed 

 in showing the presence of the electricity, &c. ; circumstances 

 which, as we shall see, all have an influence upon the degree 

 of facility with which the two electric principles follow some 

 certain course, or become again immediately united to the 

 same surface from which by chemical action they are separated. 



When a capsule of platina filled with sulphuric or diluted 

 nitric acid is placed upon the plate of a condenser, and a plate 

 of zinc, held in the fingers, is immersed in it, a very feeble 

 charge is given to the plate of the condenser, although the che- 

 mical action may have been very lively ; the reason is, not that 

 there has not been an enormous disengagement of electricity, 

 a fact which may be proved by employing this electricity in 

 producing a current; but in this experiment the negative elec- 

 tricity developed in the zinc unites with the positive with much 

 greater facility than it can pass through the fingers and the 

 body of the experimenter in order to lose itself in the earth ; 



