[437

Prop. X: Prob. V.

Gyretur corpus in Ellipfi: ‚requiritur. lex vis centripet@ tendentis ad

centrum Ellipfeos,

Sunto C A, CBfemiaxes Ellipfeos;‚GP, DK diame-tri conjugatzx; P F,Q+ perpendiculaad. diametros; Quordinatim applica-ta ad diametrumGP;& fi complea-tur parallelogram-mum 0© RP, erit(ex Conicis)P vGad 0 quad, utPC quad. ad CDquad,&(* ob fimi-lia triangula Qt, PCF)Qvquadeltad Okt quad ut PC quad,ad P Fquad,&conjunckis rationibus, P v G ad Qt quad. ut PC quad,‘ adCD quad,& P C quad. ad P F quad, id eft vv Gad in ut PCAquad. A ‚-Scribe Q_R pro Po,&(per Lemma

x.) BC xCAproCDxP F, necnon( pundkis P& Q_coeun-tibus) 2PC pro vG,& dußis extremis& medijs in feQi4x PC7 2BCAXCAmutuo,— wquale LEE Elt ergo

ne&

(per

Sand

Corol. Theor.V.) vis centripeta reciproce wa X ef

Cob