j6 First published Paper on Electricity 



nth, I2th, and I3th propositions: but it is needless to point out the 

 agreement, as the explanation given by the authors does it sufficiently. 



128] 6. On the Leyden vial. 



The shock produced by the Leyden vial seems owing only to the great 

 quantity of redundant fluid collected on its positive side, and the great 

 deficiency on its negative side ; so that if a conductor was prepared of so 

 great a size, as to be able to receive as much additional fluid by the same 

 degree of electrification as the positive side of a Leyden vial, and was 

 positively electrified in the same degree as the vial, I do not doubt but 

 what as great a shock would be produced by making a communication 

 between this conductor and the ground, as between the two surfaces of 

 the Leyden vial, supposing both communications to be made by canals 

 of the same length and same kind. 



It appears plainly from the experiments which have been made on 

 this subject, that the electric fluid is not able to pass through the glass; 

 but yet it seems as if it was able to penetrate without much difficulty to 

 a certain depth, perhaps I might say an imperceptible depth, within the 

 glass ; as Dr Franklin's analysis of the Leyden vial shews that its electricity 

 is contained chiefly in the glass itself, and that the coating is not greatly 

 over or undercharged. 



It is well known that glass is not the only substance which can be charged 

 in the manner of the Leyden vial ; but that the same effect may be produced 

 by any other body, which will not suffer the electricity to pass through it. 



129] *Hence the phenomena of the vial seem easily explicable by 

 means of the 22nd proposition. For let ACGM , Fig. 20, 

 represent a flat plate of glass or any other substance 

 which will not suffer the electric fluid to pass through 

 it, seen edgeways ; and let BbdD, and EefF, or Bd and 

 Ef, as I shall call them for shortness, be two plates of 

 conducting matter of the same size, placed in contact 

 with the glass opposite to each other; and let Bd be 

 positively electrified; and let Ef communicate with 

 the ground; and let the fluid be supposed either able 

 to enter a little way into the glass, but not to pass 

 through it, or unable to enter it at all; and if it is 

 able to enter a little way into it, let b/38d, or bS, as I 

 shall call it, represent that part of the glass into which 

 the fluid can enter from the plate Bd, and e<f>, that 



* The following explication is strictly applicable only to that sort of Leyden vial, 

 which consists of a flat plate of glass or other matter. It is evident, however, that 

 the result must be nearly of the same kind, though the glass is made into the shape 

 of a bottle as usual, or into any other form; but I propose to consider those sort of 

 Leyden vials more particularly in a future paper. 



