2^2 Dr. Herschel's Astronomical Observations 
Here the uncertainty in which the descriptions leave us, is 
that the objects in this collection may be either clusters of 
stars mixed with nebulosity, or that in consequence of the great 
distance and compression of the small stars composing a clus- 
ter which contains no nebulosity, it may put on the nebulous 
appearance. 
The fourth collection contains 12 nebulous objects, of which 
the description makes it probable that they belong to the order 
of clusters of stars. 
I, 249 is “ A considerably bright extended nebula about 4' 
“ long and 3' broad; it is easily resolvable, and I suppose with 
“ a higher power and longer attention the stars would become 
“ visible. It is brighter about the middle.'* 
Connoiss. 100 is “ A nebula of about 10' in diameter, but 
“ there is in the middle of it, a small, bright cluster of supposed 
“ stars." 
9. Of the sidereal part of the Heavens. 
The foregoing observations have proved the intimate con- 
nection between the nebulous and sidereal condition ; and 
although in passing from one to the other we have met with 
a number of ambiguous objects, it has been seen that the ap- 
parent uncertainty of their construction is only the consequence 
of the want of an adequate power in our telescopes, to shew 
them of their real form. We have indeed no reason to expect 
that an -increase of light and distinctness of our telescopes 
would free us from ambiguous objects; for by improving our 
power of penetrating into space, and resolving those which 
we have at present, we should probably reach so many new 
objects that others, of an equally obscure construction, would 
