MifceManea Curtofa. 5 



S«m* At length, came that prodigious Comet 

 of the Year 1680. which defcending (as it were) 

 from an infinite Diflance Perpendicularly towards 

 the Sun, arofe from him again with as great 

 a Velocity. 



This Comet, (which was feen for Four Months 

 continually) by the very remarkable and pe- 

 culiar Curvity of its Orbit (above all 0- 

 thers) gave the fitteft Occafion for inveftiga- 

 ting the Theory of the Motion. And the Royal 

 Obfervatqries at Paris and Greenwich having been 

 for fome time founded, and committed to the 

 Care of m.oft excellent jlftronomers ? the appa- 

 rent Motion of this Comet was moft accurately 

 (perhaps as far as Humane Skill cou'd go) ob- 

 ferv'd by Mrs. Cajfwi and Flamfieed. 



Not long after, that Great Geometrician? the 

 Illufirious Newton^ writing his Mathematical 

 Principles of Natural Philofophy^ denionitrated 

 not only that what Kepler had found, did ne- 

 ceflarily obtain in the Planetary Syftem but al- 

 fo, that all the Phenomena of Comets wou'd 

 naturally follow from the fame Principles ^ 

 which he abundantly illuftrated by the Exam- 

 ple of the aforefaid Comet of the Year 168c. 

 fliewing, at the fame time, a Method of Deli- 

 neating the Orbits of Comets Geometrically *, 

 wherein he (not without the higheft Admirati^ 

 on of all Men) folv'd a Problem, whofe Intrica- 

 cy rendered it worthy of himfelf. This Comet 

 heprov'dto move round the Sun in a Parabo- 

 lical Orb, and to defer ibe Area's (taken at 

 the Center of the Sun) proportional to the 



Times. 



Where* 



