FO ee ee 
_) 
dence, and indeed without neceflity : for it 
PHYSICAL and LITERARY. 49 
 Wueruer the fame inconfiftency of a bo- 
dy acting where it is not, has moved’ out 
Britifh philofopher to invent an aetherial 
medium much rarer than air, as the caufe of 
gravitation, I cannot fay. Inthe twenty firft 
query, at the end of his optics, he obferves, 
“that this medium is much rarer within the 
«*denfe bodies of the fun, ftars, planets and 
“© cométs, than in the empty celeftial {paces 
“ between them. And, in paffing from them 
**to great diftances, that it grows denfer and 
denfer perpetually ; and thereby caufes the 
* gravity of thofe great bodies towards one 
* another, and of their parts towards the 
“bodies ; every body endeavouring to go 
“from the denfer part of the medium towards 
*¢ the rarer.” “I am not better fatisfied with 
this hypothefis than that of Des Cartes. For, 
without lofing time upon a minute enquiry 
into the very peculiar properties with which 
this fuppofed aether muft be endued, to pro- 
duce the effetts affigned it; the fame objecti- 
on lies’ againft it, that is above urged againft 
the vortices of Des Cartes, that it is a 
new fpecies of matter invented without evi- 
_isas eafy to endue the planets with a power 
ae G which 
