446 OHM ON THE GALVANIC CIRCUIT. 



The sphere of action thus fixed by us, has, although it is infi- 

 nitely small, precisely the same circumference as that introduced 

 by Laplace, and called finite, where he lets the higher powers of 

 the distance vanish compared with the lower, the reason of which 

 may be found already in what has been stated above. The sup- 

 position of a finite distance of action in our sense would corre- 

 spond to the case where Laplace still retains higher powers of 

 distance together with the lower. 



9. The bodies on which we observe electric phasnomena are 

 in most cases surrounded by the atmosphere ; it is therefore re- 

 quisite, in order to investigate profoundly the entire process, 

 not to disregard the changes which may be produced by the 

 adjacent air. According to the experiments left us by Coulomb 

 on the diffusion of electricity in the surrounding atmosphere, 

 the loss in force thus occasioned is (during a very short con- 

 stant time), at least when the intensities are not very consider- 

 able, on the one hand proportional to the energy of the electri- 

 city, and on the other is dependent on a coefficient varying 

 according to the cotemporaneous nature of the air, but other- 

 wise invariable for the same air. The knowledge of this enables 

 us to bring the influence of the atmosphere on galvanic phoeno- 

 mena into calculation wherever it might be requisite. It must 

 however not be overlooked here, that Coulomb's experiments 

 were made on electricity which had entered into equilibrium 

 and was no longer in the process of excitation, with respect to 

 which both observation and calculation have convinced us that 

 it is confined to the surface of bodies, or merely penetrates to a 

 very slight depth into their interior ; for from thence may be 

 drawn the conclusion, of some importance with respect to our 

 subject, that all the electricity present in those experiments may 

 have been directly concerned in the transference to the atmo- 

 sphere. If we now connect with this observation the law just 

 announced, according to which two elements, situated at any 

 finite distance from each other, no longer exert any direct 

 action on each other, we are justified in concluding, that where 

 the electricity is uniformly diffiised throughout the entire mass 

 of a finite body, or at least so that proportionately but a small 

 quantity resides in the vicinity of the surface, which case does 

 not in general occur when it has entered into motion, the loss 

 which is occasioned by the circumambient air can be but ex- 

 tremely small in comparison to that which takes place when the 



