222 
Dr. Herschel's Observations on 
large as my measure of the star. The coma is very dense near 
the nucleus ; but loses itself pretty abruptly on the outside* 
though a gradual diminution is still very perceptible. 
April go. Ceres has a visible, but very small coma about it. 
This cannot be seen with low powers ; as the whole of it together 
is not large enough, unless much magnified, to make up a 
visible quantity. ' 
May 1. The diameter of the coma of Ceres, is about 5 times 
as large as the disk, or extends nearly 2 diameters beyond it. 
i3 h ip'. 20-feet reflector; power 477. The disk of Ceres is 
much better defined than that of Pallas. The coma about it is 
considerable, but not quite so extended as that of Pallas. 
May 2. ig h 20'. Ceres is better defined than I have generally 
seen it. Its disk is strongly marked ; and, when I see it best, 
the haziness about it hardly exceeds that of the stars of an 
equal size. 
Memorandum. This may be owing to a particular disposition 
of the atmosphere, which shews all the stars without twinkling, 
but not quite so bright as they appear at other times. Jupiter 
likewise has an extremely faint scattered light about it, which 
extends to nearly 4 or 5 degrees in diameter. 
April 22. Pallas, with a power of 88if, appears to be very 
ill defined. The glass is not in fault; for, in the day time, I 
can read with it the smallest letters on a message card, fixed 
up at a great distance. 
igh !?'. The appearance of Pallas is cometary; the disk, if 
it has any, being ill defined. When I see it to the best advan- 
tage, it appears like a much compressed, extremely small, but ill 
defined, planetary nebula. - o: y f - 
April 28. Pallas is very ill defined : no determined disk can 
