Coated plates in communication little affected 105 



shall be equal to that on EM; which by the preceding proposition will make 

 very little alteration in the quantity of redundant fluid in AB. 



182] COR. III. Let the bodies H and L be at an infinite distance, and either 

 of the same or different size, and let the fluid be in equilibrio. Let now the body 

 H be brought so near to AB that its repulsion on GC shall be sensibly less than 

 before. The quantity of redundant fluid in A B will be very little altered thereby, 

 provided the repulsion of the two plates on the column CG is not sensibly 

 diminished. 



For whereas when H was at an infinite distance from AB it exerted no 

 repulsion on EM, now it is brought nearer it does exert some, and its repulsion 

 on EM is very nearly equal to the diminution of its repulsion on CG, so that 

 it comes to the same thing as placing a body N in such manner as to repel EM 

 with very nearly the same force that it does CG in the contrary direction. 



183] COR. IV. Let the body H be brought near A B as in the preceding 

 corollary, and let the fluid be in equilibrio; let now an overcharged body R 

 be placed near H, the quantity of redundant fluid in H must be so much 

 diminished, in order that the fluid may remain in equilibrio, supposing the- 

 fluid in AB to remain unaltered, as that the diminution of its repulsion on the 

 two columns GC and EM shall be equal to the repulsion of R on the same 

 columns. Consequently, if the repulsion of R on them is to the repulsion which 

 H exerted on them before the approach of R as n to i, the quantity of re- 

 dundant fluid in H will be diminished in the ratio of i n to i. 



For supposing the quantity of fluid in H to be thus diminished, I say, the 

 quantity of fluid in A will remain very nearly the same as before. For the 

 repulsion of H and R on the two columns will be the same as that of H was 

 before, but it is possible that their repulsion on GC may be a little less, and their 

 repulsion on EM as much greater than that of H was before, but this, by the 

 preceding corollaries, will make very little alteration in the quantity of fluid 

 inAB. 



184] COR. V. It appears from Prop. XXIII that the repulsion of the 

 body R on the two columns GC and EM will be the same in whatever direction 

 it is placed in respect of H and the canal, provided its distance from the point G 

 is given, and consequently the diminution of the quantity of fluid in the body H 

 will be very nearly the same in whatever direction R is situated, provided its 

 distance from G is given. 



185] COR. VI. Fig. n. Suppose now that instead of the body H there is 

 placed a plate of glass Kkil, coated as in Props. XXXIV and XXXV, with 

 the plates Tt and Ss, whereof Tt communicates with AB by the canal GC, and 

 the other 5s communicates by the canal gP with the body P, placed at an 

 infinite distance and saturated with electricity, and let AB and consequently 

 Tt be overcharged, and let the fluid be in equilibrio. 



Suppose now that an overcharged body R is brought near the glass Kkil, 

 I say that the proportion which the redundant fluid in Tt bears to that in AB 

 will be very little altered thereby, supposing the length of the canal CG to be 



