Opuscula t 149 
defcribat Ellypfim AD .•■ quaeruiitur in fingulis puncflis veio- 
citates , & vires . Sumatur quodlibet pundura D , & agantur 
curvje normales A E , D G , fumptifque A P == D L — ^ demit- 
tantur ex pun(flis P, L re^flae PB, LM normales in AE, 
DG. Polito fedlionis axe Vv, & ejus centro C, vocetur CH 
= 2- , CV z=.c j parameter axis Vv = ; in reliquis retinen- 
tur fuperiores denominationes . Curvsc sequatio eft ic:p: :ce 
zz :yy , & fumptis dilferentiis ic : p : : — zds : ydy : : ^: 
atqui hatc ell formula fubnorraalis H G : igitur H G 
= — , & H G = — — : atqui z c — > : Ergo H 
z:zL^ -^pjLi igitur normalis DG = + ^'^^ yy. 
42C 4 
Eft autem D G D H : : D L .* D M , aut analytice 
}/tt -t- ^1^1 yy :y;\a\q = . '^^ . Similiter 
V — -t- — -yy 
4 2 C ■ ^ 
probabo A B = Q_ = 
2 c ~ p 
hh 
4 2 £• 
Quum velocitates in pund'is A,D fiiit reciproce ut Q_: f » 
«acdem velocitates erunt directe ut normales A E , D G , inver- 
fe ut ordinatac A F , D H . Quare in circulo , ubi normales 
omnes aequales funt , velocitates erunt in ratione reciproca or- 
dinatarum . 
Ex fuperioribus defcendit hxc sequatio — -~ ^ 
— , fumptifque dilferentiis = Hic vaior ponatur 
in aequatione fexta , lubflituta iFL pro mV » fiet fdy 
FLQ^ pUy ^ ^ FLQ* « 
= ^ — - — , live f — ; ex qua conltat potentias 
2 0. y^ 20" 
tlFe in ratione reciproca triplicata diftantiarum a plano attra" 
hente . Si fit ^ , evadit f =^ F : Ergo -^4"? ~ ^ ' ^^^^^ 
Q!/ vides, 
