Note 7 — Chapter II
Reading edition
Gravity, or the tendency of a body to approach the earth, is proportioned to the square of the distance; that is, if a body be attracted by the earth at a certain distance, with a certain force, and be afterwards removed to twice the distance, it will now be attracted, not half us much, but only one-fourth as much as it was before; and if it be removed to three times the first distance, it will be attracted not one-third as much, but one-ninth, as much as before; four being the square of two, and nine the square of three.