48 Captain Hall s observations of 
The foregoing right ascensions and declinations were de- 
termined by means of a wire micrometer attached to a power 
of about 80. The comet was always so near the horizon 
before it became visible, that on no evening during the whole 
month that it was observed, could its JR and declination be 
measured more than once. Unfortunately there were few 
known stars near the comet, so that it was often necessary 
to wait a considerable time before any one passed through 
the field of view. The high range of hills which encircle 
Valparaiso, also, interfered with these observations, as the 
comet became hid sooner than it otherwise might have been. 
During the first week the nucleus was very distinct, and 
might have been measured by the micrometer ; but I was 
then in the interior of the country, and did not commence 
observing it till the 8th, when the nucleus had become so 
indistinct as to render any measurements of this kind uncer- 
tain. Lieutenant Robertson of the Conway, assisted by Mr. 
Foster, midshipman of that ship, measured the angular dis- 
tance of the comet from Aldebaran, Sirius, and Canopus, from 
its first appearance, until the splendour of the moonlight so 
far obliterated the comet, as to prevent any good distances 
being taken. These distances are given here, as they may 
serve to determine the comet’s place, if required, for several 
days before the micrometrical observations were commenced. 
i st April 
7 P.M. 
o /II 
Aldebaran 44.42. o 
Sirius 66.52.40 
Canopus 68.10.50 
Barom. 29.91 
Ther. 61. 
43.24. o 
67. 8.30 
67.18.40 
Barom. 29.86 
Ther. 64 
2d April 
7P. M. 
3d April / 
710 P M. j 
42. 1.40 
65.28.40 
66. 5.00 
Barom. 30. 
Ther. 68 
7th April 
7.15P.M. 
Aldebaran 37.35.22 
Sirius 60.46.48 
Canopus 64.11.17 
Barom. 29.97 
Ther. 60 
8th April 
7.5P.M.' 
Barom. 
Ther. 
36.33.10 
59.45.25 
63.45.27 
29.86 
60 
9th April 
7.2 P.M. 
Barom. 
Ther. 
35 - 35 - 3 ° 
58.49.40 
63.20.40 
29.94 
62 
(The error of the index has been applied to these distances.) 
