293 OpUSCUIA • 
oppofitione figni deftrultur, fiet angulans nodorum motus = 
M H . PG . M N ^ fi MD fit finus verfus arcusMw, erit 
— > eritque 2MD ad MN ut gravitas Planetae M 
in centrum T ad vim perturbatricem P . Quare fi pro ratio- 
ne PG: MT fcribatur t : i , & quantitates materiae in Pla- 
netis T , & A fe habeant inter fe ut M : i , & fit A T — » 
"KiT — b i MFI:=±^, gravitas Planet^ M in centrum T := 
-£ , ac denique fit angulus M T w = — dz ^ evadet angu- 
, . , •±;Ta:.MN.Mr/7 -^V . h . m- x d z 
lans nodorum motus = 
ly.MT^iMD '''^^ - 
Ducitur iam ex punClo A QFig.2.'), in planura orbh* 
BM^ perpendiculum Aa^ & ex P in planum b perpen- 
diculum P F . Erit PF — jii.PG, Aa ^ ^^p^-— - =. ccra , 
Qa^-o^^T^ a^y . ^ M := ( ^ T^ -f- M T^ - 2^T.MH)^ 
= — COV^^ 4- 2^^ C I — C.*T*)^ & AM'- 
Qa^ ^ la X — w^Tr*}^ . Qiiare cum fit —7 vis , qua 
a 
pundum T trahitur perpendiculariter plano orblt^ BM^, & 
vis qua fimiliter trahitur punc^um M lit — , erit duarum 
virium differentia , nimlrum vis perpendicuhriter diltrahens PJa- 
netam M ab orbitae fuae plano zz. 
-, & angularis nodorum motus evadet — 
1 1 L Ma* 
Si Planetae attrahentis diflantia pr^e radio vefl-ore orb'taE 
adeo lit magna ut polnnt ncgligi altiores radii iphus potefta- 
tes , erit A M ~ a^ Z^l ^a^ x Q 1 — «^t*)^ , & angularis no- 
dorum motus :::: ^ ■ - C 1 — cv^T^Y .dz. Hic cafus Lunac 
elt , qux a Soie perturbatur . Qiiare fi nodi Lunaris orbitae in 
qua- 
