Royal Society. 31 
itrcngthen and maintain the concave arch of this fiicll ; for by 
what the excerient Mr. Neivton hath ihewn in his 'I'rincipia 
'Philofophlcej it will follow, that according to the general prin- 
ciple of gravity, vifible throughout the whole univerle, all thofe 
particles, that by length of time, or otherwife, fliall moulder away, 
or become loole on the concave lurface of the external fphere, 
would fall in, and with great force defcend on the internal, unlefs 
thofe particles were of another fort of matter capable by their 
ftronger tendency to each other, to fulpend the force of gravity 5 
but we know no other fubftances capable of fupportino each other 
by their mutual attraftion, but the magneticalj and thefe we 
obferve miraculoufly to perform that office, even wherp the power 
of gravity hath its full effeit, much more within the globe, where 
it is weaker ; why then may we not fuppofe, the faid arches to be 
lined throughout with a magnetical matter, or rather to be one 
great concave magnet, whofe two poles, are thofe before obierved, 
to be fixed in the furface of our globe: Another argument, 
favouring this hypothefis, is drawn from a propofition of the afore- 
faid Mr. Neivtofj, where he determines the force, wherewith the 
moon moves the fea in producing the tides 5 where he fays, ths 
denfity of the moon is to that of the earth as 680 to 587, or as 
p to 5 nearly^ therefore, the body of the moon is denier than our 
earth 5 now, if the moon be more folid than the earth, as 9 to 5, 
why may we not realbnably fuppofe the moon being a finall body, 
and a fecondary planet, to be Iblid earth, water and fione 5 and 
this globe to conflft of the fame materials, only four ninths there- 
of to be porous within, and between the internal fpheres? It muH: 
be allowed indeed, that thefe included globes can be of very little 
fervice to the inhabitants of this outward world, nor can the fun 
be ferviceable to them either with his light or heat • but fince we 
fee all the parts of the creation abound in animate things, why 
iliould we think it flrange, that the prodigious mafs of matter, of 
which this globe conlifls, fhould be capable of fome other 
improvements, than barely to ferve to fupport its iurfice? Why 
may we not rather fuppofe, that the exceeding fmall quantity of 
folid matter, in refpe61: to the fluid JEther^ is fo diipoled by the 
Almighty wifdom, as to yield as great a lurface for the ufe of 
living creatures, as can confift with the conveniency and fecurity 
of the whole? And tho' without light there can be no living, yet 
there are many ways of producing light, which we are wholly 
ignorant of 5 the medium itfelf may be always luminous, after the 
manner of our Ignes fatui'^ the concave arches may in feveral places 
iliine with fuch a fubflance as invefts the furface of the fun 5 nor 
can 
