of ascertaining the Magnitude of small celestial Bodies. 45 
8th Experiment. 
The luminous spots, or spurious disks of the globules were 
of unequal diameters. The globule No. 1 had the largest disk, 
and the smaller ones the least ; and the gradation of the sizes 
followed the order of the numbers. 
( 2. ) This agrees with the spurious disks of celestial objects : 
the stars of the first, second, and third magnitude having a 
larger spurious disk than those that are of inferior magnitudes. 
9 th Experiment. 
I found that there was a considerable difference in the colour 
of the spurious disks ; one of them was of a beautiful purple 
colour, another was inclined to orange, a large one was straw 
coloured, a small one pale-ash coloured, and most of them 
were bluish-white. 
(3 ) With respect to colours, therefore, the terrestrial also 
agree with the celestial spurious disks. 
10 th Experiment. 
I made two globules of different diameters, and placed them 
very near each other, so that their spurious disks might re- 
semble those of a double star ; this succeeded perfectly well. 
I viewed them with different powers. 
With 177, the vacancy between them is f diameter of the 
large star. 
With 232, it is if diameter. 
With 303,8, it is if diameter. 
With 432,3, it is if. 
(4.) This experiment proves that the spurious diameters 
