343

Appendix.

Eccentricity of the Orbit is continually in-casing as the Apsides pass from the Qua-dratures to the Syzygies, and vice versa.

46. It has been already shewn. (Art .

*7, 18.) that if the Plane of the Satellite’s■Orbit be inclined to the Plane in which areBodies 8'and T, the Motion of the Sa-tellite in Latitude will in no -wife be dis-turbed by the Part L M of the extraneousEorce, but only by the other Part NM,a nd not by that neither when. the Nodes'C in the Syzygies; but when they are in*he Quadratures this Perturbation is greatest°f all.

• 47. For let P be the Satellite in its Orbit pj ate

C A D, inclined to the immoveable Plane PX1X.CFD in any Angle ADF; and let P S Fig - 8 ‘e Xpound the Force of the Body S, attractingsite Satellite in the Direction P S. Prom PEt fall the Perpendicular P q to the Plane•C F D, and draw the Right Line T a S ;siren the Force P S is resolvable into theforces S q and P q ; of which the former,being in the said Plane 0 F D, ■ noes notdisturb the Satellite’s Motion in Latitude;

'hut the other Force P q , being perpendicu-lar to the Plane CFD, is wholly spent indrawing the Satellite from its Orbit G A Dtowards it, and therefore .is proportionalZ 4 to