228 PHILOSOPHICAL TRANSACTIONS. [anNO 1771. 



space, or at least in the space b,3, whose dimensions will be given below be 

 uniform and solid; and let tlie law of the electric attraction and repulsion be in- 

 versely as the square of the distance; it is required to determine in what manner 

 the fluid will be disposed both within and without the globe. 



Take the space sb such, that the interstices between the particles of matter 

 in it shall be just sufficient to hold a quantity of electric fluid, whose particles 

 are pressed close together, so as to touch each other, equal to the whole redun- 

 dant fluid in the globe, besides the quantity requisite to saturate the matter in 

 Bb; and take the space b3 such, that the matter in it shall be just able to satu- 

 rate the redundant fluid in the globe: then, in all parts of the space b^, the fluid 

 will be pressed close together, so that its particles shall touch each other; the 

 space Bp will be entirely deprived of fluid; and in the space cb, and all the rest 

 of infinite space, the matter will be exactly saturated. 



For, if the fluid is disposed in the abovementioned manner, a particle of fluid 

 placed any where within the space cb will not be impelled in any direction by the 

 fluid in Tib, or the matter in b,3, and will therefore have no tendency to move: 

 a particle placed any where without the sphere pjt will be attracted with just as 

 much force by the matter in b(3, as it is repelled by the redundant fluid in b^, 

 and will therefore have no tendency to move: a particle placed any where within 

 the space b^', will indeed be repelled towards the surface, by all the redundant 

 fluid in that space which is placed nearer the centre than itself; but as the fluid 

 in that space is already pressed as close together as possible, it will not have any 

 tendency to move ; and in the space b|3 there is no fluid to move, so that no part 

 of the fluid can have any tendency to move. 



Moveover, it seems impossible for the fluid to be at rest, if it is disposed in 

 any other form; for if the density of the fluid is not every where the same at the 

 same distance from the centre, but is greater near b than near d, a particle 

 placed any where between those two points will move from b towards d; but if 

 the density is every where the same at the same distance from the centre, and 

 the fluid in hb is not pressed close together, the space cb will be overcharged, 

 and consequently a particle at b will be repelled from the centre, and cannot be 

 at rest: in like manner, if there is any fluid in b|3, it cannot be at rest: and, by 

 the same kind of reasoning, it might be shown, that, if the fluid is not spread 

 uniformly within the space cb, and without the sphere (iii, it cannot be 

 at rest. 



Carol. 1. If the globe bde is undercharged, every thing else being the same 

 as before, there will be a space si, in which the matter will be entirely deprived 

 of fluid, and a space Bt3, in which the fluid will be pressed close together; the 

 matter in si being equal to the whole redundant matter in the globe, and the 

 redundant fluid in b|3, being just sufficient to saturate the matter in Bb: and in 



