for ascertaining the distances of clusters of stars , &c. 4,65 
In the large 10 feet telescope. 
No. 97, being too low for examination, had the appearance 
of a faint nebula. 
The numerous ambiguous objects that have been seen in 
the 20 feet telescope do not properly come under this head ; 
for as none of them have been critically examined by superior 
telescopes, they must still remain ambiguous; and it is for the 
purpose of being able to form some probable conjecture about 
the nature of these doubtful objects, that the foregoing results 
of the appearance of such as have been ascertained to be 
clusters of stars, have been pointed out. 
It would be far too extensive to enter into particular appli- 
cations, I shall therefore confine myself to a few general 
remarks. In the depth of the celestial regions, we have 
hitherto only been acquainted with two different principles, 
the nebulous and the sidereal. The light of the nebulous 
matter is comparatively very faint, and, except in a few 
instances, invisible to the eye. It is also in general widely 
diffused over a great expanse of space, in which, by an increase 
of faintness, it generally escapes the sight : the light of stars 
on the contrary, is comparatively very brilliant, and confined 
to a small point, except when many of them are collected 
together in clusters, when their united lustre sometimes takes 
up a considerable number of minutes of space; but in this 
case the stars of them may be seen in our telescopes, and by 
the observations that have been given, it appears that when 
they are viewed with instruments gradually inferior to those 
which prove them to be clusters of stars, their diameters, 
seen with less light and a smaller magnifying power, are 
