4, MiJceUanea Cur to fa. 



School-men in the mean time, being to no Pur : 



pofe. 



Next to Ticho, came the Sagacious Kepler. 

 He having the Advantage of Tichoh Labours 

 and Obfervations, found out the true Phyfical 

 Syftemof the World, and vaftly improv'd the 

 Aftronomical Science. 



For he demonftrated that all the Planets per- 

 form their Revolutions in Elliptick Orbits, whofe 

 Plains pafs thro' the Center of the Sun, obferving 

 this Law, That the Area's (of the Elliptick Sectors^ 

 taken at the Center of the Sun, which he proved 

 to be in the common Focus of thefe Ellipfes) are 

 always proportional to the Times, in which the cor- 

 refpondent Elliptical Arches are defer ib^d. He 

 difcover'd alfo, That the Difiances of the Pla- 

 nets from the Sun are in the Sefquialtera Ratio 

 of the 'Periodical Times, or (which is all 

 one) That the Cubes of the Difiances are as the 

 Squares of the Times. This great Aftronomcr 

 had the "Opportunity of obferving Two Co- 

 mets, one of which was a very remarkable one. 

 And from the Obfervations of thefe (which af- 

 forded fufficient Indications of an Annual Paral- 

 lax') he concluded, That the Comets motfd freely 

 thro the Planetary Orbs, with a Motion not much 

 different from a Rectilinear one ; but of what Kind 

 he corfd not then precifely determine. Next, He- 

 <velius ( a Noble Emulator of Ticho Brahe) fol- 

 lowing in Kepler's Steps, embraced the fame 

 Hypothecs of the Rectilinear Motion of Co- 

 mets, himfelf accurately obferving many of 

 them. Yet, he complain'*^ that his Calculations 

 did not perfectly agree to the Matter of Fadl: 

 in the Heavens : And was aware, that the Path 

 of a Comet was bent into a Curve Line towards the 



Snn't 



