34 i 'st published Paper on Electricity 



/ 4] For the future, I would be understood never to comprehend the 

 electric fluid under the word matter, but only some other sort of matter. 



5] It is indifferent whether you suppose all sorts of matter to be indued 

 in an equal degree with the foregoing attraction and repulsion, or whether 

 you, suppose some sorts to be indued with it in a greater degree than others; 

 but it is likely that the electric fluid is indued with this property in a much 

 greater degree than other matter ; for in all probability the weight of the 

 electric fluid in any body bears but a very small proportion to the weight 

 of the matter ; but yet the force with which the electric fluid therein attracts 

 any particle of matter must be equal to the force with which the matter 

 therein repels that particle; otherwise the body would appear electrical, 

 as will be shewn hereafter. 



To explain this hypothesis more fully, suppose that i grain of electric 

 fluid attracts a particle of matter, at a given distance, with as much force 

 as n grains of any matter, lead for instance, repel it : then will i grain of 

 electric fluid repel a particle of electric fluid with as much force as n grains 

 of lead attract it ; and i grain of electric fluid will repel i grain of electric 

 fluid with as much force as n grains of lead repel n grains of lead*. 



6] All bodies in their natural state with regard to electricity, contain 

 such a quantity of electric fluid interspersed between their particles, that 

 the attraction of the electric fluid in any small part of the body on a given 

 particle of matter shall be equal to the repulsion of the matter in the same 

 small part on the same particle. A body in this state I call saturated with 

 electric fluid: if the body contains more than this quantity of electric fluid, 

 I call it overcharged : if less, I call it undercharged. This is the hypothesis ; 

 I now proceed to examine the consequences which will flow from it. 



7] LEMMA I. Let EAe (Fig. i) represent a cone 

 continued infinitely; let A be the vertex, and Bb 



and Dd planes parallel to the base ; and let the cone 

 be filled with uniform matter, whose particles repel 

 each other with a force inversely as the n power of 

 the distance. If n is greater than 3, the force with which a particle at A 



is repelled by EBbe or all that part of the cone beyond Bb is as .-- s . 



For supposing AB to flow, the fluxion of EBbe is proportional to 

 - AB x AB Z , and the fluxion of its repulsion on A is proportional to 



Afi i 



2 ; the fluent of which is /~n~n4R~-3' whicn when AB is mnnite 



is equal to- nothing; consequently the repulsion of EBbe is proportional to 



i i 



' 



_ 



(n - 3) AB n ~ 3 AH" 



* [Note i, p. 352.] 



