120 Dr. Herschel’s Observations of a Comet , 
condensed into the small compass of a few minutes; and 
which of course will vanish when diluted by magnifying. 
Sept. 2, I saw the comet at Glasgow, in a 14 feet Newto- 
nian reflector ; but being very low, the moon up, and the 
atmosphere hazy, it appeared only like a very brilliant nebula, 
gradually brighter in a large place about the middle. 
The 9th and 10th of September at Alnwick, I viewed it with 
a fine achromatic telescope, and found that, when magnified 
about 65 times, the planetary disk-like appearance seen with 
the naked eye, was transformed into a bright cometic nebula, 
in which, with this power, no nucleus could be perceived. 
The 18th of September the star-like object in my large 10 
feet reflector, when magnified 110 times, had the appearance 
of a fine globular, lumininous nebula ; it seemed to be about 
5 or 6 minutes in diameter, of which one or two minutes 
about the centre were nearly of equal brightness. The small 
10 feet showed it in the same manner. 
In all my instruments this bright appearance was equally 
transformed into a brilliant head of the comet, with this dif- 
ference, that when high powers were applied, the central illu- 
mination which moderately magnified, was pretty uniform, 
became diluted into a gradual decrease from the middle to- 
wards the outside ; losing itself by imperceptible degrees, 
especially towards the sides and following parts, into a darkish 
space, which from observations that will be given hereafter, 
I take to be a cometic atmosphere. 
The Colour and Eccentricity of the Light of the Head. 
The colour of the head being very remarkable, I examined 
it with all my different telescopes ; and in every one of them. 
