NEWTONIAN PHILOSOPHY. 
s the ftruéture of t the 
te which bodies tend 
ards the fun and planets; and oe thefe powers, the 
tee of planets, and comets, the theory of the moon, 
and the tides. 
This book, which he calls «* De Mundi Syftemate,”’ he 
tells us was firft written in the popular way ; but confider- 
ing, that fuch as are unacquainted with the faid principles 
would not conceive the force of the confequences, nor be 
induced to lay afide their ancient Lata for this reafon, 
and to prevent the thing from 
coe 
: after which the author himfel direéts us to pafs on 
to the book “ De Syftemate Mundi.’ 
The feveral articles of this philofophy are a under 
their refpeCtive heads; as Sun, Moon, Pranetr, Comer, 
NT 
ARTH, P NTRA 
ETAL force, Resistance, MeEp1 » SPACE, 
ELastTicity, GRAvITyY, ral idea, or abftraé& 
of the whole, we fhall here lay before ye aa » to fhew in 
_ This ee is not 
er. See Gravity. 
of the principle from phenomena, together 
with the application of the fame aa to the various other 
appearances of nature, or t ucing thofe appearances 
from nee princi, conttitute the Newtonian fyftem ; which, 
n miniature, will ftand t 
t the oe of eed 
t, d abies 
centre ; in which the obfervations of all aftronomers agree. 
2. The fame phenomenon holds of the fatellites of Saturn 
ay pag oti to 
eart ie fom: 
times feen ftationary, and feces ete wit pad 
he powers by ec the fatellites of Jupiter are 
Gili 
with regard to Saturn ; egard to the 
earth, and of the prmary cence ” with regard to the 
III. The moon gravitates towards the earth, and by the 
power of that gravity is retained in her orbit ; and the fame 
holds of the other fatellites with refpe& to their primary 
planets ; and of the ep rimaries with refpeét to the fun. See 
Gravity and Moon 
As to the other noel planets, their bs naga = 
ee to their prim 
‘A gai n, attraction is al- 
ways mutual, 7. ¢. the aon is equal to the a@tion: con- 
fequently, the primary planets gravitate towards their {e- 
h towards the moon, and the fun to- 
And this gravity, with regard to each fe- 
parate planet, is Scag as the fquare of its diltance 
from its centre of gravity. 
ll bodies pela towards all the planets; and 
their ‘weights towards any one planet, at equal diftances 
from the centre of ig planet, are proportional to the quan- 
a of matter in e 
r the law of de defcent of waa bodies towards the 
eat, fetting afide their ae retardation from the refift- 
ance of the air, is this, t all bodies fa Il ees in seu 
rived at once of all progreflive 
dropped ee ts the earth; it is fhewn, that 
in equal times they would defcribe equal {paces with the 
moon; and, therefore, that their quantity of mattter is to 
that of the moor, as their weights to its weight. Add, that 
fince Jupiter’s fatellites revolve in times that are ina fefqui- 
plicate ratio of their diftances from the centre of Jupiter, 
and confequently at equal diftances from Jupiter, their accele- 
rating gravities are equal ; therefore, falling equal altitudes 
in equal times, they will defcribe equal f{paces, juit as heavy 
bodies do on our eart re ae 
uantities of mat- 
n anets towards the q 
matter inthe planets and fatellites. And hence are feveral 
orollaries drawn relating to the weights of bodies on the 
V. Gravity extends itfelf towards all bodies, and is in 
proportion to the quantity of matter in eac 
at all the planets gravitate towards each other has = 
jee fhewn ; likewife, that the gravity towards any on 
confidered apart, is reciprocally as the {quare of its ditance 
rom the centre of the planet ; confequently, gravity is abe 
m. Farther, as the part 
B; 
of the periodical times, inverfely ; and t 
diftance from the centre of the planet are greater or lefs in a 
duplicate ratio of their diftances, inverfely ; and fince Bs 
quantities of matter in the planets are as their pow 
equal diftances from their eh and, laftly, ince ‘te 
weight 
