A. M. Mayer — Experimental Proof of Ohrrfs Law. 43 



" With regard to this first law, I have started from the sup- 

 position that the communication of the electricity from one 

 particle takes place directly only to the one next to it, so that 

 no immediate transition from that particle to any other situate 

 at a greater distance occurs. The magnitude of the transition 

 between to adjacent particles, under otherwise exactly similar 

 circumstances, I have assumed as being proportional to the 

 difference of the electric forces existing in the two particles ; 

 just as in the theory of heat, the transition of caloric between 

 two particles is regarded as proportional to the difference of 

 their temperatures. It will thus be seen that I have deviated 

 from the hitherto usual mode of considering molecular actions 

 introduced by Laplace ; and I trust the path I have struck 

 into will recommend itself by its generality, simplicity, and 

 clearness, as well as by the light it throws upon the character 

 of former methods. 



With respect to the dispersion of electricity in the atmos- 

 phere, I have retained the law deduced from experiments by 

 Coulomb, according to which, the loss of electricity in a body 

 surrounded by air, in a given time, is in proportion to the force 

 of the electricity, and to a coefficient dependent on the nature 

 of the atmosphere. A simple comparison of the circumstances 

 under which Coulomb performed his experiments, with those 

 at present known respecting the propagation of electricity, 

 showed, however, that in galvanic phenomena the influence of 

 the atmosphere may almost always be disregarded. In Cou- 

 lomb's experiments, for instance, the electricity driven to the 

 surface of the body was engaged in its entire expanse in the 

 process of dispersion in the atmosphere ; while in the galvanic 

 circuit the electricity almost constantly passes through the 

 interior of the bodies, and consequently only the smallest 

 portion can enter into mutual action with the air ; so that in 

 this case, the dispersion can comparatively be but very incon- 

 siderable. This consequence, deduced from the nature of the 

 circumstances, is confirmed by experiment ; in it lies the 

 reason why the second law seldom comes into consideration. 



The mode in which electricity makes its appearance at the 

 place of contact of two different bodies, or the electrical 

 tension of these bodies, I have thus expressed : when dissimilar 

 bodies touch one another, they constantly maintain at the 

 point of contact the same difference between their electro- 

 scopic forces [potentials]. 



With the help of these three fundamental positions, the 

 conditions to which the propagation of electricity in bodies of 

 any kind and form is subjected may be stated. The form and 

 treatment of the differential equations thus obtained are so 

 similar to those given for the propagation of heat by Fourier 



