232 Dr. Herschei/s Observations of a second Comet , 
20th. These calculations may however be repeated, if here- 
after we should obtain elements improved by additional obser- 
vations, made with fixed instruments ; but the result, I may 
venture to say, will not be materially different. 
The distance of the comet from the earth, the 20th of Ja- 
nuary when its apparent diameter was determined, was 1,0867, 
the mean distance of the earth from the sun being 1 ; whence 
we deduce a very remarkable consequence, which is, that the 
real diameter of its nucleus cannot be less than 2637 miles. 
The Chevelure of the Comet. 
Instead of that bright appearance, which in the first comet 
has been considered as the head, there was about the nucleus 
of the second a faint whitish scattered light, which may be 
called its chevelure. 
Jan. 1. Examining the chevelure of the comet with a 10 
feet reflector, I found that it surrounded the nucleus, not in 
the form of a head consisting of gradually much condensed 
nebulosity, but had the appearance of a faint haziness, which 
although of some extent, was not much brighter near the 
nucleus than at a distance from it. 
Jan. 2. I viewed the two comets alternately. The first 
could only be distinguished from a bright globular nebula by 
the scattered light of its tail, which was still 2 a 20' long. The 
second comet, on the contrary, had nothing in its appearance 
resembling such a nebula : it consisted merely of a nucleus, 
surrounded by a very faint chevelure ; and had it not been for 
an extremely faint light in a direction opposite to the sun, it 
would hardly have been intitled to the name of a comet; 
