Confirudtlon of the Heavens* 249 



refpe£t the vifual ray might alfo be faid to reach. To make 

 this appear we muft return to the naked eye, which, as wc 

 have before eftimated, can only fee the flars of the feventh 

 magnitude fo as to diftlnguifh them ; but It is neverthelels very 

 evident that the united luftre of millions of flars, iuch as [ 

 fuppofe the nebula in Aiidromedato be, will reach our fight in 

 the fhape of a very fmall, faint nebuloiity ; fmce the nebula of 

 which I fpeak may eafiiy be ittw in a line evening. In the 

 ■fame manner my prefent telefcope, as I have argued, has not 

 only a vifual ray that will reach the flars at 497 times the dif- 

 tance of Sirius fo as to diftinguifh them (and probably much 

 farther), but alfo a power of iliewing the united luilre of the 

 accumulated flars that compofe a milky nebulofity, at a diilance 

 far exceeding the former limits ; fo that from thelc conildera- 

 tions it appears again highly probable, that my prefent telefcope, 

 not fhewing fuch a nebulofity in the milky way, goes already far 

 beyond its extent : and conlequently, much more would an 

 inftrument, fuch as I have mentioned, remove all doubt on 

 the fubje£t, both by fhewing the flars in the continuation of 

 the flratum, and by expofing a very flrong milky nebuMty 

 beyond them, that could no longer be miflaken for the dark 

 ground of the heavens. 



To thefe arguments, which refl on tlie firm bafis of a feries 

 of obfervation, we may add the following confiderations drawn 

 from analogy. Among the great number of nebuliE which I 

 have now already feen, amounting to more than 900, there 

 are many which in all probability are equally extenfive with 

 that which we inhabit ; and yet they are all feparated from each 

 ether by very confiderable intervals. Some indeed there are 

 that feem to be double and treble.; and though with moll of 

 thefe it may be, that they are at a very great diilance from each 



Vol. LXXV. K k ' other. 



