of ascertaining the Magnitude of small celestial Bodies. 39 
gee a celestial body under the same angle, I could never mis- 
take it for a small star. The angle it subtends is o ",999. 
I see the diameters of No. 2 and 3 very clearly, and can 
divide them by estimation into two parts, half of No. 3 is o",3i 1 . 
I see No. 4 and 5 as round bodies, but cannot divide them 
by estimation. The diameter of No. 5 is o", 45. No. 6 may 
also be seen, but 7 and 8 are invisible. 
These objects reflecting too little light, the silver globules 
of the 3d experiment were placed on the tree. It will be right 
to mention that they were all so far tarnished by having been 
out in the open air for more than a fortnight, that no improper 
reflection was to be apprehended. 
The air being uncommonly clear, I saw with 502,6 the glo- 
bules No. 1, 2, 3, 4, 5, and 6, as well defined black balls. I 
could easily distinguish £ of the diameter of No. 6 ; which is 
With 415,7 I saw them all round as far as No. 10 included. 
With 502,6 I saw No. 9 and 10 very sharp and black, and 
could divide No. 10 into two parts, each of which would be 
©V34- 
With a new lens, power 759,7, I saw No. 10 better than 
with 502,6, and could with ease distinguish it into halves, or 
even third parts of its diameter. of it is o",o89. 
With 223,1 I saw them all as far as No. 10 included as 
visible objects, but the smallest of them were mere points. 
No. 6 might be divided with this power into two parts ; each 
being o",279. 
With 292,1 I saw No. 10 sharp and round. The magnified 
angle is only 1' 18", 3. One half of No. 6 may be perceived 
with great ease. 
