Fic. IIL 
Fic. IV. 
204 DE Causa Paysica FLruxus 
Hx & P Mrefpe@tivè parallelæ duabus diametris conjuga- 
ts, quæ fibi mutud occurruntin r, junéta 4 r erit parallela 
rectæ x m per hoc Lemma. 
Cor. 3. Sitrecta H P nunc parallela Axi Ellipfeos, erit- 
que Angulus HP M æqualis Angulo HP m,quoniam © M: 
qm: NP : P Q:P q per Cor. 1. Ducantur porro H# 
& P F parallelæ alteri Axi a & occurrant Axi Bb in D 
& d; fuper Axem D d defcribatur Ellipfis fimilis Ellipf 
AB ab & fimiliter pofita cui occurrat reda wr produéta im 
IN &n; occurrat#r Axi D d in”, eritque 7’ N vel V# 
æqualis re@tæ er, & fi jungantur D » , D N erunt hæ reétæ 
refpedivè parallelæ reëtis P M, Pm.NamPe:er::Pq: 
gm:& He:er:: Hq:qx;,undeHexPe:er*:: HqxqP: 
mqxqx:: CB: : CA. Sed Reétangulum D x F4: 
VN:::CB::CÆ°;du—He, D V—Pe,adeoque D P, 
xVd=—HexPe,unde/ Mer, ,&V N=er,P M 
parallela reëtz D N& P m reêtæ D r. 
Con. 4. Hinc fequitur conversè quod fi V'x fit ordinata 
abinteriori Ellipf ad Axem D d & D p perpendicularis Axi 
D d occurrat Ellipli exteriori in P ; jungantur D N & D n 
hifque parallelæ P M, P m occurrant Ellipfi exteriori in AZ 
& m ; ducatur P H parallela Axi D d , in quam fint perpen- 
diculares Me &mgq,tumPO+Pq(vel2Pe) erit 
æqualis 2 D pundis Ÿ & q cadentibus ad eafdem partes 
punéti P , & PO —P q—= 2 D V cum 9 & 4 funt ad con 
trarias partes punéti P. 
LEmMmMA IL 
Re&a P L perpendicularis Ellipfi 4B abin P occurrat 
Axi B bin L , & ex punéto L fit LZ perpendicularis in fe- 
midiametrum CP , eritque Reëtangulum CP Z contentum 
fub fefnidiametro € P & intercepta P Z æquale quadrata 
ex femiaxi C A. 
Sit Cp femidiameter conjugata ipli CP, ducatur PD 
perpendicularis in Axem B à & producatur donec occurrat 
femidiametro Cp in K, jungatur KZ, fitque PT rangens 
