Kirliwoocl.] 



216 



[Xov. 19, 



Comets whose Aphelion Distances are Nearly Equal to 5.20, the Radius 

 of Jupiter^ s Orbit. 



II. 



Comets whose Aphelion Distances are Nearly Equal to 9.54, the Badius 

 of Saturn's Orbit. 



illi Comets whose Aphelion Distances are Nearly Equal to 19.18, the 

 Badius of Ur emus' s Orbit. 



iV. Comets ichose Aphelion Distances are Nearly Equal to 30.04, the 

 Badius of Neptune'' s Orbit. 



The coincidences here pointed out (some of whicli liave been noticed by 

 others,) appear, tlien, to be necessary consequences of the motion of tlie 

 solar system through spaces occupied by meteoric nebulae. Hence the 

 observed facts receive an obvious explanation. 



In regard to comets of long period vre have only to remark that, for any 

 thing we know to the contrary, there may be causes of perturbation far 

 exterior to the orbit of Neptune. 



3. From what we observe in regard to the larger bodies of the universe 

 ' — a clustering tendency being everywhere apparent, — it seems highly 

 improbable that cometic and meteoric matter should be uniformly diffused 

 through space. We would expect, on the contrary, to find it collected in 

 cosmical clouds, similar to the visible nebulae. Now, this, in fact, is pre- 

 cisely what has teen olssrved in regard both to comets and meteors. In 



