Confii'ucilon of the Heavens. 249 



refpe^t the vlfual ra}^ might alfo be faid to reach. *Vq make 

 this appear we mufl return to the naked eye, which, as we 

 have before eilimated, can only fee the ilars of the fevcnth 

 magnitude fo as to diftinguifh them ; but it is neverthelcfs very 

 -evident that the united lurtre of millions of ilars, fuch as I 

 fuppofe the nebula in Andromeda to be, will reach our fight in 

 the Ihape of a very fmall, faint nebulofity ; fmce the nebula of 

 which I fpeak may eafdy be feen in a fine 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 io as to diftinguifli them (and probably mucii 

 farther), but alfo a power of ihewing the united luftre of the 

 accumulated ftars that compofe a milky nebuiofity, at a diifance 

 far exceeding the former limits ; 10 that from thefe conlidera- 

 tions it appears again highly probable, that my preient teleicopey 

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

 beyond its extent : and confequently, much more would an 

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

 the fubjeft, both by (hewing the ftars in the continuation of 

 the flratum, and by expofing a very flrong milky nebulontv 

 i)eyond them, that could no longer be miftaken for the dark 

 ground of the heavens. 



To thefe arguments, which reft on the firm bafis of a feries 

 -of obfervation, we may add the following confiderations drawn 

 from analogy. Among the great number of nebulcC which 1 

 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 

 other by very confiderable intervals. Some indeed there are 

 that feem to be double and treble; and though Vv^ith mou of 

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



Vol. LXXV\ K k ' ' other, 



