[ 339 J 
By thefe advances, we have likewife attained to a 
more certain knowlege of that medium , which feems 
to fur-round the Jurfaces of all bodies , and which, 
being of a greater or lefs denfity, or exerciflng (if I 
may fo fay) a greater or lefs refinance, produces dif- 
ferent effects, as the eledtric fluid (or cether , if you 
pleafe) pafes in and out of bodies , whenever they are 
diflurbed by any external violence j and, were it not 
for this medium Jurrounding all bodies , the electric 
fluid, I apprehend, could neither be accumulated , nor 
detained , in any body whatfoever. 
This principle is very Ample, and feems to be of a 
very general nature. Our great pkilofopher adopted 
it from many experiments : he fuppofed, that the 
wonderful phenomena of nature , particularly thofe 
of light , were not to be explained without it; and 
therefore did not fcruple to propofe it, as a principle, 
to be farther inquired into. 
I fhall think my time well employed, if, by thefe 
inquiries, I have at all contributed to fhew, how much 
we are indebted to this happy Interpreter of Nature , 
and have afforded frefh occaflon, by the light of his 
labours, to admire, and adore, the firft caufe of all 
things. But whatever may be the fuccefs of my en- 
deavours, they have at lead been attended with a la- 
tisfadion, which not a little increafes that deflre I 
have ever had for purfuits of this kind. I am. 
S I R, 
Your moft obliged humble fervant. 
Great Queen-ftreet, London, 
Nov. 9th, 1759. 
Benja. Wilfon. 
X x 2 
XXXVI. 
