A 



SYNOPSIS 



OF THE 



Aftronomy of Comets. 



THE ancient Egyptians and Chaldeans 

 (if we may credit Dlodorus Siculas) 

 by a long Courfe of Obfervations, 

 were able to predid the Apparitions 

 of Comets. But fince they are alfo faid, by 

 the Help of the fame Arts, to have prognofti- 

 cated Earthquakes and Tempefts, 'tis pall all 

 Doubt, that their Knowledge inthefe Matters, 

 was the Refult rather of meer Analogical Cal- 

 culation, than of any Agronomical Theories of the 

 Coeleftial Motions. And the Greeh y who were 

 the Conquerors of both thofe People, 'fcarce 

 found any other fort of Learning amor^ft 

 them, than this. So that 'tis to the Grceh 

 themfelves as the Inventors (and efpecially to 

 the Great Hipparchw) that we owe this Agro- 

 nomy, which is now improv'd to fuch a Heigth. 

 But yet, amongft thefe, the Opinion of Ari- 

 (rotle (who wou'd have Comets to be nothing 

 but Sublunary Vapours, or Airy Meteors) 

 A pre- 



