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conftruftionem) eft ergo Ke asqualis K unde 
eft pun&um K ad parabolara foco A & vertice princi- 
pal! C defcriptam. jQ. E . D. 
Bifefto autem angulo A K E a refta KB, tanget 
hxc utramqj parabolam, tam foco F per A < 3 C K , quam 
foco per K defcriptam. Unde fe mutuo tangunt 
parabola, Q. E. D. 
Errat Pag*. 151. /. ult . pro /. P£., 
FINIS. 
L O tf D O N~: 
Printed for W. and J. Innys, Printers to the Royal 
Society 5 at the Sign <of the Prince Arms t the Weft- 
End of SuE aul' s-Churcb'Tard. 
