The Great Comet of 1861. . 263 
Dr. Pape of Altona has examined carefully the question 
whether the earth was at any time within the tail of the comet, 
and concludes that at its nearest approach we were about 
2,400,000 miles distant from its nearest edge, on the morning © 
of June 29th at 2h 24m, 
This result (so far as it relates to the principal ray) is also 
indicated by Mr. Hall’s calculations communicated in the earlier 
notice. Mr. Hall states the difference of the heliocentric longi- 
tude of the comet and of the earth, at the passage of the node, 
June 28-086 Washington mean time, to be 2° 00’ and the log. 
distance of the comet from the earth 9:1529. 
Dr. Pape finds for the nodal passage June 28:10 Washington 
Mean time, difference of longitudes =1° 59’. The results in 
other particulars are also substantially the same. 
The following remarks have been translated from Dr. Pape’s 
article in No. 1316 of the Astronomische Nachrichten: 
“From the position of the comet with respect to the sun and 
the earth, we might conjecture the latter to have berm: through 
the tail of the comet on the 28th or 29th of last June. As such 
a collision is of some interest, I have undertaken a slight calcu- 
lation to obtain closer details. The passage of the comet through 
its ascending node took place, Berlin time, June 28°35 (28°10 
ashington). : 
At this time, its true anomaly was 29° 37", log. r=9°94449, its 
heliocentric longitude 278° 59’, its distance from the earth’s orbit 
=0'1161. At the same time the heliocentric longitude of the 
earth was 277° 0’. Assuming that the axis of the tail coincided 
With the prolongation of the radius vector, the earth was at a 
distance of 0-0852 from this axis. (Mean distance of the earth 
That point of the tail which lay in the earth’s orbit was at a dis- 
f =('1162 from the nucleus; to determine the diameter of 
the tail at that point, I subjoin an observation of the 3d of July. 
0 of that day, the angle which the 
on the evening } 
Prolongation of the radius vector of the comet formed with the 
omet, was =57° 40’; a point in 
rection from the earth to the ¢ 
the tail (which could be traced for about 60 degrees) at a distance 
=0°1162, had an apparent distance of 42° 24’ from the nucleus, 
and at the same time that the distance of this point from the 
earth =0°1457. 
Ata fashies of about 42° from the nucleus, the breadth of 
the tail may have been 3°; hence it follows that its true diameter 
was 00076. 
_ Now on June 28°35, the distance of the e 
the tail was 0:0352, so that the nearest partic 
arth from the axis of 
les of the tail passed 
