W. A. Norton— Coggia’s Comet. 165 
communicated by R. S. Newall to A. C. Ranyard, showing 
the aspect of the comet, as seen at Ferndene on July 12th. In 
the accompanying description* it is stated that “the nucleus 
was very bright, with a disk tolerably well defined. In front 
of the nucleus (i. e. on the side toward the sun) was a fan- 
shaped light which seemed to arise from the overlapping or du- 
plication of the two tails, which streamed away behind (the 
nucleus) for a length of about 15°, forming, as it were, two 
luminous veils, delicate, transparent and flickering, having be- 
tween them a black space well defined up to the nucleus. The 
edges of these tails appeared to be brighter than the middle 
part, and crossing over the nucleus they formed the sides of the 
; the outside edges also crossing over formed the top of the 
fan and head of the comet. In front of this was another cov- 
ering semicircular and brightest in the preceding part, and in 
front of that was again another fainter envelope or cloud. 
This outer faint envelope, or duplex envelope, has been a no- 
ticeable feature in the aspect of other comets (e. g. Donati’s). 
et 
I. 
Physical structure and condition of the Comet.—Upon the vari- 
ous drawings made by different observers, Mr. Ranyard has 
the following remarks:+ ‘The drawings that were made o 
Coggia’s comet during the early part of July, 1874, show that 
although there was but one small almost stellar nucleus, there 
were two sets of parabolic envelopes situated side by side, 
ently overlapping one another just in front of the nucleus. 
* Month. Notices of Astr. Soc., 1875-6, p. 279. + Ibid. 
