“— ~ 2. 
—— A 
a 
PHYSICAL ano LITERARY. 43 
Vfaac Newton, to whom the great difcovery 
was referved, that the defcent of heavy bo- 
* 
dies, and the curvilinear motion of the pla- 
nets, are effects of the fame caufe, choofes 
to talk of this property of matter with great 
circumfpection and referve. He pretends on- 
ly, in his Principia, to have afcertained the 
facts, without venturing to point out the 
caufe. In the general /cholium, which con- 
cludes that elaborate work, he fatisfies himfelf 
with having explained ‘the motion of the 
“ celeftial bodies, and of the fea, by the force 
“of gravity, without affigning the caufe of 
** gravity.” He only obferves, ‘* That gravi- 
*‘ ty muft be the effe& of fome caufe, which 
*< penetrates into the very center of the fun 
‘and planets, and which as not in propor- 
<‘ tion to the furfaces, but the folid quantity 
‘of matter; its action only decreafing ina 
“duplicate ratio of the diftances.”” And 
adds, ‘“* That he has not been able to,find 
out from phoenomena, the reafon of thefe 
_ * properties of gravity, and that he does not 
** choofe to deal in hypothefes.” It need not 
be furprifing, that this great philofopher 
_ fhould be referved upon the caufe of a theory 
fo extenfive and fo wonderfull, when it 
was 
