132 Dr. Herschel's Observations of a Comet , 
The 16th. With the naked eye the tail was nearly de- 
grees long. 
The 19th. Its length was about 6° 10'. 
Dec. 2. The tail was hardly 5 degrees long and of a very 
feeble light. 
The 9th, the length of the tail was not materially altered. 
The 14th, it still remained as before, but the end of it was 
much fainter. 
Increasing Darkness between the Streams that inclose the Tail. 
The 4th of November the darkness near the head on the 
side from the sun was grown more conspicuous, and much 
less filled up with scattered light. 
The 5th, the darkness of the atmosphere on the side oppo- 
site the sun was stronger than on the sun side. 
The 10th. A considerable darkness prevailed between the 
two branches of the tail. 
The 14th. In the tail, close to the head, there was a large 
space almost free from scattered light ; where the small stars 
of the milky-way are as bright as if nothing had intercepted 
their light. 
The 16th. The space between the streams was of a consi- 
derable darkness. 
The 19th. 10 feet reflector. The darkness between the 
streams was increased. 
Dec, 9. The space close to the head on the side from the 
sun was quite dark, or rather transparent. 
The 14th. Many small stars of the milky- way were in the 
dark interval of the tail close to the head of the comet. 
