made with a View to investigate its Magnitude , See. 149 
On examining the comet, I found the diameter of its nucleus 
to be certainly less than the largest of my globules, which 
being ,04 66 inch, subtended an angle of 3", 97 at the distance 
of the telescope in the day time. 
Comparing the nucleus also with the impressions, which 
the view of the second and third had left in my memory, and 
of which the real diameters were ,0325 and ,0290 inch ; and 
magnitudes at the station of the mirror 2", 77 and 2", 47, I 
found that the comet was almost as large as the second, and 
a little larger than the third. 
Oct. 18. The nucleus is less than the globule which sub- 
tends 2", 77. 
Oct. 19. The air being uncommonly clear, I saw the comet 
at 40 minutes after five, and being now at a considerable alti- 
tude, I examined it with 289, and having but very lately re- 
viewed my globules, I judged its diameter to be not only less 
than my second globule, but also less than the third ; that is, 
less than 2", 47. 
Oct. 6. The 20-feet reflector, notwithstanding its great 
light, does not show the nucleus of the comet larger than the 
10-feet, with an equal magnifier, makes it. 
Oct. 28. My large 10-feet telescope, with the mirror of 24 
inches in diameter, does not increase the size of the nucleus. 
Oct. 6. Being fully aware of the objections that may be 
made against the method of comparing the magnitude of the 
nucleus of the comet with objects that cannot be seen toge- 
ther, I had recourse to the satellites of Jupiter for a more 
decisive result, and with my 7-feet telescope, power 202, I 
viewed the disk of the third satellite and of the nucleus of the 
comet alternately. They were both already too low to be seen 
