I 

 4.2 First published Paper on Electricity 



in AD. For a like reason, if AD and EH are both undercharged, the re- 

 dundant matter in EF is half the difference of the redundant matter in 

 those spaces; and if A D is overcharged, and EH undercharged, the re- 

 dundant fluid in CD exceeds half the redundant fluid in AD, by a quantity 

 sufficient to saturate half the redundant matter in EH. 



32] COR. II. It was before said, that the fluid in the spaces AB and 

 GH (when there is any fluid in them) is repelled against the planes A a 

 and Hh; and, consequently, would run out through those planes, if there 

 was any opening for it to do so. The force with which the fluid presses 

 against the planes A a and Hh, is that with which the redundant fluid 

 in AB is repelled by that in GH; that is, with which half the redundant 

 fluid in both spaces is repelled by an equal quantity of fluid. Therefore, 

 the pressure against A a and Hh depends only on the quantity of redundant 

 fluid in both spaces together, and not at all on the thickness or distance 

 of those spaces, or on the proportion in which the fluid is divided between 

 the two spaces. If there is no fluid in AB and GH, a particle placed on 

 the outside of the spaces AD and EH, contiguous to the planes A a or Hh, 

 is attracted towards those planes by all the matter in AB and GH, id est, 

 by all the redundant matter in both spaces; and, consequently, en- 

 deavours to insinuate itself into the space AD or EH; and the force with 

 which it does so depends only on the quantity of redundant matter in 

 both spaces together. The fluid in CD also presses against the plane Dd, 

 and the force with which it does so is that with which the redundant fluid 

 in CD is attracted by the matter in EF. 



33] COR. III. If A D is overcharged, and EH undercharged: and the 

 redundant fluid in AD is exactly sufficient to saturate the redundant 

 matter in EH, all the redundant fluid in AD will be collected in the space 

 CD, where it will be pressed close together : the space EF will be intirely 

 deprived of fluid, the quantity of matter therein being just sufficient to 

 saturate the redundant fluid in CD, and the spaces AC and FH will be 

 everywhere saturated. Moreover, if an opening is made in the planes A a 

 or Hh, the fluid within the spaces AD or EH will have no tendency to 

 run out thereat, nor will the fluid on the outside have any tendency to 

 run in at it : a particle of fluid too placed anywhere on the outside of both 

 spaces, as at P, will not be at all attracted or repelled by those spaces, 

 any more than if they were both saturated ; but a particle placed anywhere 

 between those spaces, as at 5, will be repelled from d towards e; and if a 

 communication was made between the two spaces, by the canal de, the 

 fluid would run out of AD into EH, till they were both saturated. 



34] PROP. VIII. PROB. 4. To determine in what manner the fluid will 

 be disposed in the space AD, supposing that all the rest of the universe 

 is saturated with immoveable fluid, and that the electric attraction and 

 repulsion is inversely as some other power of the distance than the square. 



