206 G. Th. Fechner's Justification of the 



which, I confess, I do not consider De la Rive's experiments 

 to be entirely free. 



I. Facts iichich refer to the unclosed circuit. 



1. I have given in these Annals (vol. xli. p. 225) the means 

 of proving with certainty the not inconsiderable amount of 

 electricity which two heterogeneous metals acquire by contact 

 in an insulated state. The supporters of the chemical theory 

 are accustomed either to deny the certainty of these experi- 

 ments, a denial which will henceforth be rendered impossible 

 by the application of the methods here stated, or to derive 

 the electricity thus originated from friction, pressure, or the 

 chemical influence of the air and its moisture. It is to be 

 shown that the result cannot depend on these. I must how- 

 ever remark previously, that it appears to me somewhat 

 strange to allow to friction and pressure, which after all are 

 only particular modifications of contact, the property of ex- 

 citing electricity, independent of chemical action, while it is 

 so obstinately denied to the simple contact. Nor has it even 

 once been tried to derive thermo-electricity from chemical 

 action: the agency of contact is here undoubted. 



That the result, in the above-mentioned experiments, can- 

 not depend on friction, has already been shown in my memoir 

 in these Annals, vol. xli. p. 235, under No. 4.*. That it does 

 not depend on pressure, is evident partly for this reason; that 

 wherever the contact is completely effected, which naturally 

 cannot take place entirely without pressure, an increase of the 

 pressure does not indicate any more evident influence on the 

 power of the shocks ; and partly, that, according to the experi- 

 ence of Becquerel (so very extensive on this subject) all bodies 

 are capable of having electricity excited in them by pressure, 

 with the single exception however of the case, in which both 

 bodies pressed together are good conductors, in which it at 

 least cannot be demonstrated, undoubtedly for the same rea- 

 son which hinders the demonstration of the electricity pro- 

 duced through the friction of two good conductors. But 

 that chemical action cannot be the cause of the result follows 

 already indirectly for this reason ; that in this case the con- 

 densation of the electricities at the surfaces of contact would 

 be entirely inexplicable, which on the other hand is very easily 

 explained according to the voltaic theory. In fact, it is self- 

 evident, that, if a force exists in the contact of both plates, 

 which can separate and transfer to the respective plates the 

 electricities, notwithstanding their attraction for each other, it 

 must also be capable of keeping them separate in a degree 

 proportional to the intensity of that force. 



* The statement here alluded to will be given in the sequel of this 

 translation. Edit. 



