g from the earth.

"COR. 1.--There is, therefore, a power of gravity tending to all the
planets; for doubtless Venus, Mercury, and the rest are bodies of the
same sort with Jupiter and Saturn. And since all attraction (by Law
iii.) is mutual, Jupiter will therefore gravitate towards all his own
satellites, Saturn towards his, the earth towards the moon, and the sun
towards all the primary planets.

"COR. 2.--The force of gravity which tends to any one planet is
reciprocally as the square of the distance of places from the planet's
centre.

"COR. 3.--All the planets do mutually gravitate towards one another, by
Cor. 1 and 2, and hence it is that Jupiter and Saturn, when near their
conjunction, by their mutual attractions sensibly disturb each other's
motions. So the sun disturbs the motions of the moon; and both sun and
moon disturb our sea, as we shall hereafter explain.

"SCHOLIUM

"The force which retains the celestial bodies in their orbits has been
hitherto called centripetal force; but it being now made plain that it
can be no other than a gravitating force, we shall hereafter call it
gravity. For the cause of the centripetal force which retains the moon
in its orbit will extend itself to all the planets by Rules i., ii., and
iii.

"PROPOSITION VI., THEOREM VI.

"That all bodies gravitate towards every planet; and that the weights
of the bodies towards any the same planet, at equal distances from the
centre of the planet, are proportional to the quantities of matter which
they severally contain.

"It has been now a long time observed by others that all sorts of heavy
bodies (allowance being made for the inability of retardation which they
suffer from a small power of resistance in the air) descend to the earth
FROM EQUAL HEIGHTS in equal times; and that equality of times we may
distinguish to a great accuracy by help of pendulums. I tried the thing
in gold, silver, lead, glass, sand, common salt, wood, water, and wheat.
I provided two wooden boxes, round and equal: I filled the one with
wood, and suspended an equal weight of gold (as exactly as I could)
in the centre of oscillation of the other. The boxes hanging by eleven
feet, made a couple of pendulums exactly equal in weight and figure, and
equally receiving the resistance of the air. And, placing the one by the
other, I observed them to play together forward and backward, for a long
time, with equal vibrations. And therefore the q