The Great Comet of 1861. 309 
The comet was much fainter to-night. The tail was not more 
than 25° in length, and curved very nearly the same as on pre- 
vious nights, but was broader, being nowhere less than 3° in 
width. The western and the main branches seemed both sub- 
divided continually. 
The luminosity surrounding the head was more extended than 
before, but with no perceptible outline. | 
The sector was much smaller and fainter, and for the greater 
part of the time could scarcely be discerned at all as distinct 
from the general mass of light. The vertex of its upper, convex 
side was some 5° or 10° to the right of the comet’s axis, corres- 
ponding very nearly to the position of the line or brush of light 
Seen on the 3d inst. The inner edge of the eastern cusp was 
better defined than that of the western,—it was concave as usual, 
while the western, when it could be seen at all, was quite straight. 
ere was no trace whatever of any dark spots or lines, except 
that by occasional glimpses a shade could be suspected separa- 
ting the outer luminosity from the sector, but even this was very 
doubiful 
July 7.—Although there were thin cirri extending over all 
that portion of the sky, the cometary nature of the body was 
Tecognizable as early as 88 5™, An hour later, the thin clouds 
had all disappeared. ; 
At 10% p. M. the light of the nucleus was brighter than that of 
* Urse Majoris. With a power of 70, and the full aperture of 
the equatorial, it was, in comparison with the night of the 5th, 
condensed aad brilliant, but not stellar. 
‘he head, or what has hitherto been called the sector was not 
unlike an arrow-head in form. 
The anterior boundary of the sector was more flattened than 
on previous evenings, and was not unlike an arrow-head greatly 
expanded perpendicular to the axis of length. A brush of lu- 
minous fibres extended from the nucleus across it, inclined to 
the west at an angle of 8° or 10°, and perceptible 20” beyond 
the boundary. That wing was the smaller, and much the less 
Tegular in outline. The curve of the posterior boundary also 
nm ore flattened, but neither ehicsin: was well-defined, al- 
though the night had become perfectly clear. 
he weakaek branch of the ales could be traced from the nu- 
cleus to near 6 Bootis, the eastern one to about a degree beyond 
vand » Herculis, and the latter stars were precisely in its line, 
At 8° from the nucleus the two were not more than 13° to 2 
broad. The great volume of light was within 10° of the nu- 
cleus, and at 20° the brillianey of the coma did not exceed that 
of the milky way, west of y Aquile. But its intensity was sub- 
ject to great changes, when it seemed to flow from the nucleus 
I a stream steadily increasing for some minutes, and again as 
