* 
with a Conjecture, fuggefting a Mean, Sc.’ 20$ 
haps like Saturn's ring, bé provided on both fides of it, witham- 
ple means of making it a fuitable place for habitation : the habi- 
tation of myriads of millions of animate beings, equal or fuperior 
to thofe, which people our planetary fyftem. | 
Beyond that orb, at proper diftances, it is:conceivable, there 
might be other concentric orbs, equally fuitable for habitation, 
and alike inhabited : including within’ them: innumerable 
fyftems of "planets, refembling the folar fyftem, and like that 
animated, and adorning the infinite expanfe» . 
To this hypothefis objections may be made; and füch as might 
ftars) of 
T aids: according to. aftronomical obfervations, poflefs 
the fame relative place ; or are, in refpest of each other, fixt, 
But how are the exterior fyftems (fappofing the whole not 
boundlefs) prevented from approaching towards the common 
centre. of gravity © from which, if they. have. no.revolution 
round it; (which: the like obfervations ‘make: probable) they 
‘cannot be kept by a projectile or centrifugal force ? Muft they 
"not conftantly by that law be drawn, with an accelerating mo- 
tion, 
