Comet II. 1862. 203 



lias faded and been replaced by a fresh emission at another 

 angle ; the only reason for the latter supposition is that, in the 

 position occupied by the feather last night, there is a cloud, 

 very slightly more luminous than the surrounding coma, in 

 which a similar form may be traced ; this is visible with a 

 moderate power, but with 27 it extends further, and reaches 

 down to the arc, so as to recall the feeble sector of August 

 18th, of which the faint cloud may form the most luminous 

 part. It is possible that the nucleus may lie at the vertex, 

 or in the course, of a parabola of haze, of which the left side 

 may be traced in the drawing of last night, but this is un- 

 certain ; the set-off in the coma has faded so as to be barely 

 perceptible : the colours in the head continue unchanged. The 

 tail has closed up again so that the darker interior is filled in, 

 and the whole looks narrower ; the longer side is now much 

 best defined on its right or external edge, the other being 

 diffused in comparison ; it may be readily followed with the 

 comet eye-piece through 3|°, and, precariously, as far again; 

 both with this power and the finder it is seen to enlarge for 

 some distance behind the head, and subsequently to taper off 

 to a thin stream ; its general aspect in the finder is straight. 

 Position of chord of luminous arc, measured about lOh. 5m. 

 G.M.T. gives 279°; a little later, 280°; about lOh. 35m. 281°'5. 

 Fig. 3 is a sketch of the head. 



August 25. Much cirrous haze, and the comet, though 

 evidently much brighter than heretofore, is probably never 

 quite clear. Another great change is shown with 27. The 

 bright arc has totally disappeared, not a trace of it remaining 

 with any power ; and the feather has returned, in its previous 

 form and position, being (9h. 15m.) the only perceptible feature 

 in the head ; it is, however, longer than before, and with greater 

 proportional breadth, about one-third of its length, and much 

 less distinguished from the coma, which may possibly be con- 

 densing towards the centre of the head. The nucleus is so 

 exceedingly faint as barely to be made out with, any eye-piece, 

 the feather being only a trifle brighter at the quill end, which, 

 like the other end, is broader than on August 22nd. 460 shows 

 that either extremity is brighter than the centre ; the broad 

 end seems to occupy the exact position of the faint cloud of 

 August 23rd. The edges of the feather are far less sharp than 

 on August 22nd, nor do I think this, or the feebleness of the 

 nucleus, chiefly due to our atmosphere, as the head is very 

 brilliant, both with the comet eye-piece and to the naked eye. 

 Measurement defeated by clouds, but position of chord of 

 feather at llh. 10 in. guessed, very roughly, about 240°. See 

 fig. 4, which represents only the centre of the head. 



August 27. Sky very hazy. Nucleus not distinguishable 



