Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/50

6 that may erve exactly to retain a body in a given orbit with a given velocity; and vice vera, to determine the curvilinear way into which a body projected from a given place, with a given velocity, may be made to deviate from its natural rectilinear way, by means of a given force.

The quantity of any Centripetal Force may be conidered as of three kinds: Abolute, Accelerative, and Motive.

Thus the magnetic force is greater in one load-tone and les in another, according to their izes and trength.

Thus the force of the ame load-tone is greater at a les distance, and les at a greater: alo the force of gravity is greater in valleys, les on tops of exceeding high mountains; and yet les (as hall hereafter be hewn) at greater ditances from the body of the Rh