Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 2.djvu/525

 [ 61 ] angle of the ditances from the foci. But in orbits like thoe of the planets, the rules as they are delivered above are ufficient of themelves without further correction.

=
o========= POSTSCRIPT UPON reviewing thee few heets after they were printed off, which happened a little ooner than I expected, I fear the apology I have offered for delivering the propoitions relating to the Moon's motion, in this rude manner, without giving any proof of them, or o much as mentioning the fundamental principles of their demontration, will carcely pas as a atisfactory one ; epecially ince there are among thee propoitions, ome which, I am apt to think, cannot eaily be proved to be either true or fale, by any methods which are now in common ue. WHEREFORE to render ome atisfaction in this article, I hall add a few words concerning the principles from whence thee propoitions, and others of the like                                          nature