atmospherical refraction at Port Bowen. 
223 
Table X. 
Observations for determining the Apparent Altitude of « Aquilrn at the time of setting, by Lieutenant 
Foster’s upper telescope. 
The corresponding Observations for Refraction are contained in Tables XI. and XII. 
tm 
Apparent altitude 
-3 2 
deduced from the 
Barom r . 
at Temp. 
Day. 
Time. 
0 § 
«*-. +5 
0 ce 
Mean reading of 
four Verniers. 
Correction for 
Apparent zenith 
distance. 
apparent zenith 
distance by the 
Temp. 
Winds True. 
Remarks. 
. > 
0 
ratio of the No. of 
+ 48». 
Faht. 
a 
Index 
Level. 
observations. 
1825. 
an. 28 th 
h. 
At 11 
rn. 
A. M. 
30 P. M. 
8 
H 
0 , , 
3 2 3 7 57>5 
* 78 38 30,0 
n 
0,0 
n 
+ 1,0 
+8,25 
0 / „ 
85 23 29,81 
0 / u 
I 4 36 25,97 
Inches. 
29,970 
© 
— 29,5 
Occasion- 
ally squally 
— 
8 S 23 37,20 
Feb. 7 th 
— 11 
A. M. 
8 
323 8 20,0 
0,0 
—°>s 
85 23 32,44 
| 4 36 22,17 
— — 
2 
P.M. 
8 
*286 18 5,0 
— 
+ °>75 
85 23 43,22 
29,455 
— 22,5 
North mod. 
9th 
— 10 
A.M. 
8 
323 8 1,25 
0,0 
+ 3>° 
8 ? 23 30,53 
} 4 36 21,67 
— — 
1 
P.M. 
H 
*115 32 16,25 
— 
+ 2,25 S5 23 44,18 
29,701 
— 35>7 
Calm 
Fine & clear 
Fine 
— 10th 
— 10 
30 A. M. 
6 
*152 21 51,25 
— 
+ 3,25 
85 23 39,08 
| 4 36 21,46 
1 
30 P. M. 
6 
*304 43 41,25 
— 
— 2,0 
85 23 38,00 
30,100 
— 35> 5 
Calm 
— 15 th 
— 11 
A.M. 
12 
*304 43 8,75 
— • 
+ 2,50 
85 23 3 5 >94 
4 36 24,06 
29,600 
— 33 
Cloudy, 
— 28th 
— 11 
A,M. 
6 
*152 22 1,25 
— 
—3,5° 
85 23 39,62 
^ 4 3<5 23,13 
overcast weather. 
1 
30 P. M. 
6 
*3° 4 43 25,00 
“ 
+ 1,00 85 23 34,12 
29,992 
— 21 
NE Light 
Clear & fine 
Mean — the a PP a rent altitude, upper telescope 4 36 13,08, being the altitude used in Table XI. 
Micrometrical measure of subtended at the board between the telescopes — 4 . 8,42 
Apparent altitude for the lower telescope 4 39 31,50, being the altitude used in Table XII. 
The principal vernier not reset to zero, and the observations are continued from the preceding 
reading. 6 
t The number and parts of a revolution in this case being 3 rev - 96 we obtain 3' 9", 22 for the 
angular distance between the telescopes used in the observations on refractions. The focal length, 
however, of the telescope to which the micrometer was attached being in the present case 46,19, instead 
of 46 as before stated, and the above angular distance being reduced in the ratio of 46,19 to 46, we have 
3 8 ,42 for the correct angle subtended by the distance between the upper and lower telescopes. 
