Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/19

 ''In this third Edition, the reitance of mediums is omewhat more largely handled than before; and new experiments of the reitance of heavy bodies falling in air are added. In the third Book, the argument to prove that the Moon is retained in its orbit by the force of gravity is enlarged on. And there are added new obervations of Mr''. Pound's of the proportion of the diameters of Jupiter to each other: The are beides added Mr. Kirk's ''obervations of the Comet in 1680. the orbit of that Comet computed in an ellipis by Dr. Halley; and the orbit of the Comet in 1723. computed by Mr.'' Bradley.