124 Lieut. Foster's corrections to the reductions of his 
Table X. page 223 ; Part IV. for 1826, 
Observations for determining the apparent altitude of a Aquilse at the time of setting, 1 
Lieutenant Foster's upper telescope 
The corresponding observations for refraction are contained in Tables XI and XII; pages 224 and 225 irt Part IV. for 1826 
1825 . 
Time. 
No. 
Mean readings of 
four Verniers. 
Correction for 
Day. 
of 
Obs. 
Index 
Level. 
th 
Jan. 27 
at 11** A. M. 
8 
0 / 0 
323 7 57.5 
0 
0,0 
+ 0 
// 
10,9 
— 
q p. M. 
14 
* 78 38 30 
— 
+ I 
29^2 
Feb. 8 
II A.M. 
8 
323 8 20 
0,0 
— 0 
5.4s 
— 
2 P. M. 
8 
*286 18 5 
— 
+ 0 
8,17 
9 
10 A.M. 
8 
323 8 1,25 
0,0 
+ 0 
32,7 
I P. M. 
14 
=^115 32 16,25 
— 
+ 0 
24.52 
10 
io| A.M. 
6 
* 152 21 51,25 
— 
+ 0 
35.42 
— 
i| P.M. 
6 
* 304 43 41.25 
— 
-0 
21,80 
*5 
II A. M. 
12 
*304 43 8,75 
— 
+ 0 
27.25 
28 
II A.M. 
6 
152 22 1,25 
— 
— 0 
38.15 
' 
P.M. 
6 
304 43 25 
+ 0 
10,9 
Apparent 
zenith distance. 
85 
85 
85 
85 
85 
85 
85 
85 
85 
85 
85 
23 31^05 
23 43>o3 
22 21,82 
23 44^5 
23 34’24 
23 45^77 
23 44,44 
23 34 > 7 o 
23 38,0 
23 33>85 
23 35^77 
apparent zenith 
distance in the 
ratio of the No. 
of observations. 
0/1, 
4 36 22,10 
I 4 36 22,02 
I 4 36 19.17 
I 4 36 20,43 
{ 
4 36 22,00 
4 36 25,19 
Bar. at 
Temp. 
+ 48°. 
Temp. 
Tab. 
Winds true. 
Inches. 
29.970 
0 
— 29,5 
.{ 
29.455 
— 22,5 
) North, 
5 moderate 
29,701 
— 35>7 
) Calm,fine 
3 and clear 
30,100 
-35.5 
Calm 
29,600 
— 33 
Cloudy over 
29,992 
— 21 
N. E. light. 
Remarks. 
Occasional 
squally. 
u / »/ O I /f 
Mean to be used in Table XI. . . = 4 36 21,82, instead of 4 36 23,08 
Micrometrical measure between Telescopes as before + 3 8,42 
Altitude to be used in Table XII.=4 39 30,24, instead of 4 39 31,50 
The principal vernier not reset to zero, and the' observations are continued 
from the preceding reading. 
P. S. It is to be regretted, that the observations by Lieu¬ 
tenant Ross, given at the end of the Paper alluded to, must 
now be wholly rejected; in consequence of the original 
observations involving the erroneous datum dependent upon 
the level, having been left on board the Fury at the time of 
her loss. 
The extremely low temperature of the atmosphere, in 
