{ ) 
' The Solid generated by the Po rtion O NV T abo ut 
the Axis C P; is eqtol tp i xILV^^^^^^^^TTN' — iQT* 
Froiji the Points, M, H, drop the two perpendiculars 
MZ, HW, upon CA prolonged if need be 5 tbv Sur- 
face generated by the Conver fion ot the Arc HM u bout 
the Axis CA 'is equal to ■ x PCx HM RA"^ WZ, 
when the point Z is next to C,or PC x H^MRA x WZ 
when the point W is next to it. >^ ' ^ 
Thofe that will think it worth their while to be- 
ftow fome little pains to find the Demonftration of 
this, may folve the following Problem. 
Any two Conic Seftions being given, forming 2l Lu- 
nula, by their Interfeftion, and a right line being given 
by portion, about which, aJ an Axis, i\m Lunula \% 
imagined to turn, to find the Solids generated by the 
Converfion of any of its parts, cut olF by lines per- 
pendicular to that axis, or parallel to it, or making 
any given Angle with it, as alfo the Surfaces made by 
that Converfion. if -^^^- ■ 
