[ 7* J 
IV. On Nebulous Stars , properly fo called* 
By William Herfchel, LL.D. K R . & 
Read February 10, 1791. 
I N one of my late examinations of a fpace in the heavens, 
which I had not reviewed before, I difcovered a Jlar of about 
the Sth magnitude , fur rounded with a faintly luminous atmofphere , 
of a confiderabk extent . The phenomenon was fo ftriking 
that I could not help reflecting upon the circumftances that 
attended it, which appeared to me to be of a very inftruClive 
nature, and fuch as may lead to inferences which will throw a 
confiderable light on fome points relating to the conftruCtion 
of the heavens. 
Cloudy or nebulous .{tars have been mentioned by feveral 
aftronomers ; but this name ought not to be applied to the 
objeCts which they have pointed out as fuch ; for, on examina- 
tion, they proved to be either mere clufters of flars, plainly 
to be diftinguifhed with my large inftruments, or fuch nebu- 
lous appearances as might be reafonably fuppofed to be occa- 
fioned by a multitude of liars at a vaft difiance. The milky 
way itfelf, as I have fhewn in fome former Papers, confifts 
intirely of ftars, and by imperceptible degrees I have been led 
on from the moft evident congeries of fiars to other groups in 
which the lucid points were fmaller, but ftill very plainly to 
be feen ; and from them to fuch wherein they could but barely 
be fufpe&ed, till I arrived at laft to fpots in which no trace of 
4 a ftar 
