Power acts; according to that Law, throughout all Nature; 'tis evident that as the Earth is ſixty Semi-diameters diſtant from the Moon, a heavy Body muſt neceſſarily fall (on the Earth) fifteen Feet in the firſt Second, and fifty four thouſand Feet in the firſt Minute.
Now a heavy Body falls, in reality, fifteen Feet in the firſt Second, and goes in the firſt Minute fifty four thouſand Foot, which Number is the Square of ſixty multiplied by fifteen. Bodies therefore gravitate in an inverſe Ratio of the Squares of the Diſtances; conſequently, what cauſes Gravity on Earth, and keeps the Moon in its Orbit, is one and the ſame Power; it being demonſtrated that the Moon gravitates on the Earth, which is the Center of its particular Motion, 'tis demonſtrated that the Earth and the Moon gravitate on the Sun which is the Center of their annual Motion.
The reſt of the Planets muſt be ſubject, to this general Law; and if this Law exiſts, theſe Planets muſt follow the Laws which Kepler diſcover'd. All
