Conf ruction of the Heavens. 249 
fefpeft: the vifual ray might alfo be faid to reach. To make 
this appear we mull return to the naked eye, which, as we 
have before efKmated, can only fee the ftars of the feventh 
magnitude fo as to diftinguifli them ; but it is uevertheiefs very 
evident that the united 1 11ft re of millions of ftars, filch as f 
fuppofe the nebula in Andromeda to be, will reach our fight in 
the fhape of a very fmal'l, faint nebulofitv ; ft nee the nebula of 
which I {peak may eafily be feen in a tine evening. In the 
fame manner my prefen t telefcope, as I have argued, has not 
only a vifual ray that will reach the ftars at 497 times the dift 
tance of Sirius fo as to diftinguifli them (and probably much 
farther), but alfo a power of (hewing the united luftre of the 
accumulated ftars that compofe a milky nebulofity, at a diftance 
far exceeding the former limits ; fo that from thefe confidera- 
tions it appears again highly probable, that my prefen t telefcope, 
not fire wing 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 fhewiog the ftars in the continuation of 
the ft ra turn, and by expofing a very ftrong milky nebulofity 
beyond 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 confederations drawn 
from analogy. Among the great number of nebula? 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 fepa rated from each 
other by very confiderable intervals. Some indeed there are 
that feem to be double and treble; and though with moft of 
thefe it may be, that they are at a very great diftance from each 
Vol. LXXV. K k other. 
