( ^6ii ) 
rbave computed this Table fo far, that the 'Reader 
viuay fee in what matmer this Method Approximates ; 
this whole Work, as it appears, coding a little more than 
three Hours time. 
Y. Troprietates Jtmj)Uces Sedionum Coni- 
-carum ex natura Focorum deduSliC ; cutn Tl^eore-' 
mate gener alt de Vtnhus Centrij>etis 5 quorum ope Lex 
"Virlum Centri pet arum ad Focos Setiionum tenden- 
tium, yelocitate.s Corporum in illis reyolventiuniy 
Vejcriptio Orhium facdlime deter?ninantur. Ter 
Abr. de Moivre, R. S. Soc. 
S it D £ Axis Tranfverfus Ellipfeos, AO Axis*alter, 
& C centrum Sedionis. Sic F pundum quodvis 
in circumferentia ejus ; P ^ Tangens curvsc ad P, oc- 
currens Axi Tranfverfo ad punda S, F Foci ; C P, 
C K femidiametri Conjugata: ; P H Semilatus redum 
ad diametrum FC; ? G normalis adTangenrem, cui oc- 
currac HG, perpendicularis ipfi F C in punda G, ut 
fiat FG radius Curvaturac Ellipfeos in pundo P,* fint 
etiam S F, CP, FF perpendiculares in Tangentem 
F ^dcmidae : Jungatur S'O, & demittatur in Axem 
normalis P L. His pofitis. Died quod, 
I. Re6iangulum [ub cP (I ant Us ab utroque Ellipfeos Focc, 
■five S P xU F <equaie ejl -qua Jr at 0 Semfdiametri C K» 
Demonjlratio. 
f S q~P Cq CS q — ^CS L per 
P Fqz=t P Cq CS q -F vC S x C L per iz. \\. Elem, 
Unde PSq‘\-PFq — zPCq-\-zCSq. 
Jam P S -]- P F —D E —zzC D\ ac propterea 
T S a -\~ P F q z P S x P Fz=: ^CPq. Quare 
