41^ M. R. Kohlrausch's Thewy of the 



the electricities which have thus penetrated the glass have not 

 been able to participate in the discharge; and their motion 

 within the insulator is so slow, that for the short duration of a 

 discharge they may be considered as motionless. Notwith- 

 standing the quickness of the discharge, however, a state of 

 equilibrium must establish itself, because, during the same, both 

 coatings have been connected by conductors with the earth. If, 

 therefore, the potential of the electricity which has remained in 

 the glass be not zero for a point on the coating formerly charged 

 with positive electricity, i. e. should the actions of these electrical 

 masses on the said point not annul one another, then electricity, 

 from some source or other, must have accumulated on the con- 

 ducting parts of the system, in this instance on the coatings, in 

 order to have produced equilibrium with that in the glass. As 

 to the nature of this latent electricity, as it is called, it is evident, 

 in Franklin's plate for instance, that negative electricity will now 

 be present on the side of the coating which is turned towards 

 the glass, i. e. which is next to the positive stratum in the glass, 

 and which had a positive charge imparted to it at the commence- 

 ment. For inasmuch as a so-called excess of electricity was at 

 first present on this coating, it cannot be assumed that the elec- 

 tricity which has here penetrated the glass is less than that on 

 the other side, and consequently the conclusion is forced upon 

 ns, that the action of this positive stratum on its adjacent coating 

 will be greater than that exerted on it by the more distant nega- 

 tive stratum. This unequal action can only be met by assuming 

 a suitable quantity of negative electricity on the inner side of one 

 of the two coatings. As it would be without meaning, however, 

 to place this quantity, a greater in this case, on the side of the 

 glass which is occupied by negative electricity, it must be con- 

 ceived as being present on the other side, i. e. under the coating 

 which was formerly positive. 



On the other hand, however, it is evident, if this state of things 

 had actually existed, that the residue capable of being collected 

 on the reinsulated side would but be equal to the difference of 

 the positive electricity within the glass and the latent, negative 

 electricity under the coating. But experiment shows that the 

 collected residue approaches more to an equality with the loss of 

 disposable charge, the less the electricity which is lost in the air, 

 that is to say, the shorter the time during which the plate is 

 allowed to remain charged ; so that there can be no doubt that 

 these two quantities would be exactly equal could all loss of 

 electricity be avoided. 



Thus it appears to be proved that the potential of the elec- 

 tricity, which during the discharge remained in the glass, must 

 be assumed as zero in reference to the interior of the coating 



