128 
Dr. Herschei/s Observations of a Comet , 
The Disappearance of the transparent Part of the Atmosphere 
under the Cover of the scattered Light of the contracted Enve- 
lope. 
Nov. 4. In the night-glass, that part of the atmosphere 
which used to separate the envelope from the head, could no 
longer be distinguished. 
In the 10 feet reflector, with a large double eye-glass, I 
found the envelope drawn nearer to the head, its central dis- 
tance at the vertex being less than 7' 10"; and the atmosphere 
was almost involved in the scattered haziness of the streams. 
Nov. 5. The envelope was still disengaged from tiie head, 
but much scattered light had nearly effaced the cometic atmo- 
sphere on the side towards the sun. 
Nov. 9. The atmosphere was nearly covered by the ap- 
proximation, or scattering light, of the envelope. Its vertical 
distance was 5' 45". 
Nov. 10. The envelope could only be distinguished from 
the head by a small remaining darkish space, in which the 
atmosphere might still be seen. The vertical distance of the 
envelope was 4' 4 6". 
Nov. 13. The atmosphere was almost effaced by scattered 
light towards the sun, but on the opposite side it was darker, 
or rather more transparent. 
Nov. 14, 1 5, and 16. The atmosphere was gradually more 
covered in. 
Nov. 19. I found in the 10 feet telescope, the envelope so 
broad and scattered as to leave no room for seeing the atmo- 
sphere ; and the comet seemed to be fast returning to the 
mere appearance of a nebula. 
