308 Gilliss on the Physical Aspects of 
than during the last night. Its greatest extent from the nucleus 
y a mean of five measures in the direction of the axis of the 
comet was 140”, and in a line perpendicular thereto—the extrem- 
ity of the east wing—about one-third greater, or 180”. The out- 
line of the western half was broken as it was last night, and the 
surface of that wing was much mottled. 10° or 12° to the 
westward of the axis, and forming an angle of 45° with it, there 
emanated a narrow brush of light which was traceable in the 
field of the equatorial for 30”. The posterior edge of the sector 
was again curved as on the night of the 2d, that of the eastern 
half being an unbroken line, whilst the western one was quite 
irregular. Moreover, there was a fan-shaped bundle of rays to 
the latter, which shot from the nucleus to a distance of 18" or 
20” in a line perpendicular to the axis of the sector. 
The outer envelope so well seen on the night of the 8d could 
not be traced in the equatorial, and was perceptible in the field 
of the comet-seeker only at intervals and by indirect vision. 1t 
preserved its slender crescent outline and was concentric with 
the sector, but separated from it by a dark space of about 70", 
At 94 7™ the coma was plainly divisible into two branches of 
which the bifurcation was just above x Draconis. \ The angle at 
which the western branch curved from the longer one was from 
3° to 4°. The great volume of the light was of a delicate cream 
eolor, and was within 8° of the nucleus, from which it gradually 
diminished in brilliancy. The eastern edge was the best defined, 
but neither of them was sharp, and the western one was more 
brushy, and curved outwardly more than heretofore. Above the 
point of separation of the two branches, the western one sprei 
into quite a broad fan-shape whose outer borders rapidly dimin- 
ished in light as far as the line joining « Draconis and ¢ Urs® Ma 
joris; and exeept during the occasional pulsations, it wholly fa 
ded from sight within five degrees upward from that line. _Dur- 
ing these periods, the curve could be traced to the cluster of stars 
near 6 Bootis. The great bend of the curve was on or near the 
line joining 6 Urse Majoris and » Draconis, A dark space inter 
vened between its eastern line and the eastern branch of the coma 
« and + Draconis and 1, ¢, 7 and ¢ Herculis were all within that 
and 
could be followed to the scattered light of the milky way east of 
a Ophiuchi, The periodical fluctuations in its brightness wer 
not so remarkable as on either of the other evenings. eo 
July 6.—Clouds broke away and the comet was found with : 
unassisted eye at 8415"; it was obscured with oceasional — 
ruptions by clouds until 104 when the sky became hopeles#}¥ 
overcast. 
