204 PHILOSOPHICAL TRANSACTIONS. [aNNO 177 1. 



collected in bS, and all the deficient in e^, so as to leave Brf and ^f saturated; 

 then, if the electric repulsion is inversely as the square of the distance, a par- 

 ticle of fluid placed any where in the plane bd, except near the extremities b and 

 d, will be attracted with very near as much force by the redundant matter in e(p, 

 as it is repelled by the redundant fluid in bS; but if the repulsion is inversely as 

 some higher power than the square, it will be repelled with much more force by 

 bS, than it is attracted by eip, provided the depth b(i is very small in respect of 

 the thickness of the glass; and if the repulsion is inversely as some lower power 

 than the square, it will be attracted with much more force by e:p, than it is re- 

 pelled by bi. Hence it follows, that if the depth to which the fluid can pene- 

 trate, is very small in respect of the thickness of the glass, but yet is such that 

 the quantity of fluid naturally contained in bi, or e(p, is considerably more than 

 the redundant fluid in hS; then, if the repulsion is inversely as the square of the 

 distance, almost all the redundant fluid will be collected in bS, leaving the plate 

 nd not very much overcharged; and in like manner e/ will be not very much 

 undercharged: if the repulsion is inversely as some higher power than the square, 

 sd will be very much overcharged, and E/very much undercharged; and if the 

 repulsion is inversely as some lower power than the square, hd will be very much 

 undercharged, and E/very much overcharged. 



Suppose now the plate sd to be separated from the plate of glass, still keeping 

 it parallel to it, and opposite to the same part of it that it before was applied to; 

 and let the repulsion of the particles be inversely as some higher power of the 

 distance than the square. When the plate is in contact with the glass, the 

 repulsion of the redundant fluid in that plate, on a particle in the plane bd, id 

 est, the inner surface of the plate, must be equal to the excess of the repulsion 

 of the redundant fluid in bi on it, above the attraction of Ep on it ; therefore, 

 when the plate sd is removed ever so small a distance from the glass, the repul- 

 sion of the redundant fluid in the plate, on a particle in the inner surface of that 

 plate, will be greater than the excess of the repulsion of bi on it, above the at- 

 traction of E(p; for the repulsion of bS will be much more diminished by the 

 removal, than the attraction of Eip: consequently some fluid will fly from the 

 plate to the glass, in the form of sparks: so that the plate will not be so much 

 overcharged when removed from the glass, as it was when in contact with it. 

 Mr. C. imagines however, that it would still be considerably overcharged. 



If one part of the plate is separated from the glass before the rest, as must 

 necessarily be the case if it consists of bending materials, he guesses it would be 

 at least as much, if not more, overcharged, when separated, as if it is separated 

 all at once. In like manner, it should seem that the plate E/will be consider- 

 ably undercharged, when separated from the glass, but not so much so as when 

 in contact with it. From the same kind of reasoning he concludes, that if the 



