The Circumference of the Earth is one hundred twenty three Millions, two hundred forty nine thouſand ſix hundred Feet. This, among other Things, is neceſſary to prove the Syſtem of Attraction.
The inſtant we know the Earth's Circumference, and the Diſtance of the Moon, we know that of the Moon's Orbit, and the Diameter of this Orbit. The Moon performs its Revolution in that Orbit in twenty ſeven Days, ſeven Hours, forty three Minutes. 'Tis demonſtrated, that the Moon in its mean Motion, makes an hundred and fourſcore and ſeven thoufand, nine hundred and ſixty Feet (of Paris) in a Minute. 'Tis likewiſe demonſtrated, by a known Theorem, that the central Force which ſhould make a Body fall from the height of the Moon, would make its Velocity no more than fifteen Paris Feet in a Minute of Time. Now, if the Law by which Bodies gravitate, and attract one another in an inverſe Ratio of the Squares of the Diſtances be true; if the ſame
