4 
LIEUTENANT W. ROBERTSON’S OBSERVATIONS OF THE 
were actually written down at the time ; without the alteration of a letter or 
a figure. 
Rio de Janeiro, June 18th, 1822, at 6 h 30 m p.m. Observed a bright orbi- 
cular nebula near Canopus. On directing the telescope to it, we find it to 
have the appearance of a comet. At 6 h 40 m mean time, the following distances 
were taken with sextants : 
From Canopus ... 3 6 20 
Sirius .... 34 27 10 
a Hydrse ... 58 9 20 
a Crucis ... 47 58 50 
June 19th. The comet appeared fainter than last night. There was a thin 
haze in the sky. The following observations were taken at 6 h 40 m p.m. : 
From Canopus . . 
o 
. 11 
33 
// 
30 
Sirius . . . 
. 30 
3 
37 
a Hydrse . . 
. 46 
2 
4 7 
a Crucis . . 
. 44 
15 
30 
June 20th. Thick, rainy weather ; comet not seen. 
June 21st. Thick, cloudy weather. 
June 22nd. Fine, clear moonlight. Observed the comet without a tele- 
scope. It is still of a round shape, no tail or nucleus observed when looked at 
Avith a telescope. The following angular distances were taken at 7 h 0 m p.m. : 
From Canopus . 
o 
. . 33 
35 
// 
00 
Sirius . . 
. . 33 
12 
00 
« Hydrse . 
. . 25 
9 
45 
a Crucis . 
. . 44 
36 
25 
June 23rd. Clear weather. The following angular distances were taken 
at 6 h 34 ra p.m. : 
o / // 
From Canopus . 
. . 37 
29 
20 
Sirius . . 
. . 35 
15 
45 
a Hydrse . 
. . 21 
38 
50 
a Crucis 
. . 45 
13 
10 
