[■ 588 ] 
Lemma III. 
In like manner, if n is lefs than 3, the repulfion of 
the part between A and on A is proportional to 
AB3-»: confequently the repulfion of the matter 
between A and on A, is infinitely fmall in refpedt 
of that beyond it. 
Corollary.. 
It Is ealy to fee from thefe three lemmata, that, if 
the eledtric attradlion and repulfion had been fup- 
pofed to be inverfely, as-fome higher power of the- 
diftance than the cube; a particle could not have- 
• been fenfibly affeaed by the repulfion of any fluid, 
except what was placed clofe to it. If the repulfion 
was inverfely, as the cube of' the diflance, a particle' 
could not be fenfibly aflcdfed by the repulfion of any 
finite quantity of fluid, except what was clofe to it.. 
But as the repulfion is fuppofed to be inverfely as 
lome power of the diftance lefs than the cube, a par- 
ticle may be fenfibly afieaed by the repulfion of a- 
finite quantity of fluid, placed at any, finite diflance 
from it. 
D E F I N I T ro N; 
If the elediric fluid in any body, is by any means 
confined in fuch manner that it cannot move from 
one part of the body to the other, 1. call.it immove-. 
able: if it is able to move readily from one part to, 
iinother,, I call, it moveable. . 
I 
V. R 
