STARS. 



Star, Nebulous, is a luminous point, furrounded with an 

 immenfe vifible atmofphere. Dr. Herfchel thinks, that the 

 central point is a ftar, from its complete refemblance to a 

 ftar of equal magnitude. Allied to thefe are planetary nebulae, 

 or circular fpaces in the heavens, uniformly luminous, re- 

 fembling a planetary difc. The light of one of thefe 

 nebuls, 15" in diameter, was hardly equal to that of a ftar 

 of the 8th or 9th magnitude. Hence Dr. Herfchel fup. 

 pofes, that they can fcarcely be bodies like our fun, as a 

 part of the fun's difc, 15" in diameter, would exceed the 

 greateft luftre of the full moon. If, on the other hand, he 

 obferves, we fhould fuppofe them 10 be groups or clufters 



of ftars, at a diftance fufEciently great to reduce them to 

 fo fmall an apparent diameter, we (hall be at a lofs to ac- 

 count for their uniform light, if clufters ; or for their circu. 

 lar forms, if mere groups of itars. Perhaps they may be 

 rather allied to nebulous ftars ; for, (hould the planetary 

 nebulce, with lucid centres, be an intermediate ftcp between 

 planetary nebulse and nebulous ftars, the appearances of 

 thefe different fpecies, when all the individuals of them are 

 fully examined, might throw a confiderable light on the 

 fubjeft. The clafs of planetary nebulx with centres differs 

 only from the laft in having a bright central point. See 



NEBUtOSlTY. 



8 Catalogue 



