230 Dr. Herschel on the Quantity 
I have ascertained to be a globular cluster, containing, by a 
rough calculation, probably not less than fourteen thousand 
stars. From the known laws of gravitation, we are assured 
that this cluster must have a very powerful attractive centre 
of gravity, which may be able to keep many far distant 
celestial bodies in control. 
But the composition of an attractive centre is not limited to 
one such cluster. An union of many of them will form a 
still more powerful centre of gravitation, whose influence 
may extend to a whole region of scattered stars. To prove 
that I argue intirely from observations, I shall mention that 
another nebula, discovered by Mr. Messier in the year 1781, 
is, by the same instruments, also proved to consist of stars ; 
and though they are seemingly compressed into a much 
smaller space, and have also the appearance of smaller stars, 
we may fairly presume that these circumstances are only 
indications of a greater distance, and that, being a globular 
cluster, perfectly resembling the former, the distance being 
allowed for, it is probably not less rich in the number of its 
component stars. The distance of these two clusters from 
each other is less than 12 degrees, and we are certain that 
somewhere in the line joining these two groups there must 
be a centre of gravitation, far superior in energy to the 
single power of attraction that can be lodged in either of the 
clusters. 
I have selected these twp remarkable objects merely for 
their sinuation, which is very near the line of the direction of 
the solar motion ; but were it necessary to bring farther proof 
of the existence of combined attractions, the numerous objects 
