356 Note I : on the theory of the electric Jiuid 



This number is exceedingly small compared to the product a^, which is 

 of the order zo 20 at least. Hence r lt , the repulsion between two grammes of 

 matter entirely deprived of electricity, is of the same order as a^. 



If we consider the attraction of gravitation as something quite independent 

 of the attractions and repulsions observed in electrical phenomena, we may 



suppose 



- 



so that two saturated bodies neither attract nor repel each other. 



Now we have adopted as the condition of saturation, that neither body 

 acts on the electric fluid in the other. But since neither body acts on the other 

 as a whole [gravitation now being a separate phenomenon] , each has no action 

 on the matter in the other, so that our definition of saturation coincides with 

 that given by Cavendish. 



Lastly, let the two bodies not be saturated with electricity, but contain 

 quantities F 1 + E l and F 2 + E z respectively, where F l = a^M^, and F 2 = a^M^, 

 and E l and E 2 may be either positive or negative, provided that F + E must 

 in no case be negative. 



The repulsion between the bodies is 

 (F l + EJ (F 2 + E 2 ) - (F, + x ) M 2 2 - (F 2 + E 2 ) M.a, 

 and this by means of equations (3) (4) and (10) is reduced to 



Theory of Two Fluids. 



In the theory of Two Electric Fluids, let V denote the quantity of the 

 Vitreous fluid and R that of the Resinous. 



Let the repulsion between two units of the same fluid be b, and let the 

 attraction between two units of different fluids be c. 



Let the attraction between a unit of either fluid and a gramme of matter 

 be a, and let the repulsion between two grammes of matter be r. 



If a body contains V 1 units of vitreous, R t units of resinous electricity, and 

 M 1 grammes of matter, its repulsion on a unit of vitreous electricity will be 



VJ) - Rf - M&, 



and the repulsion on a unit of resinous electricity 



- VjC + RJ - M ,!. 



The definition of saturation is that there shall be no action on either kind of 

 electricity. Hence, equating each of these expressions to zero, we find as the 

 conditions of saturation 



