170 Lieut. Foster’s observations on the diurnal changes 
North end of Needle to the S. E. 
The needle was held in equilibrio 
at this point by two bar magnets ; one to the North, with its 
nearest end from the centre of the compass 26,3 inches; the oth 
er to the South, having its nearest 
end from the centre of the compass 26,6 inches ; the axis of each magnet was slightly inclined to 
the meridian, and the needle under their influence made 1 vibration in ii,£ seconds, the directive 
power being reduced 
in the ratio of 0,24 to 1 nearly. 
Temp. 
Fahreu 1 , 
Direction of 
Date, 
Mean 
Time of 
Obser- 
A.M. 
or 
Reading of 
north end of 
north end of 
needle during 
westerly daily 
Time that a ho- 
rizontal needle 
took to make 
Winds. 
Weather. 
Remarks, &c. 
P.M. 
needle. 
Instr. 
vation. 
variation. 
60 vibrations. 
1825 . 
h. m. 
0 / 
O 
m. s. 
Apr. 1 2th 
6 30 
A. M. 
S 44 00 E 
+ 3 
18 17,4 
ESE 
Hazy 
Max. easterly var. 
7 00 
43 3 ° 
+ 3 1 
Fresh 
took place at 
8 00 
43 i° 
+ 4 
...... 
18 20,3 
o h 3 m A. M. 
9 32 
43 °° 
+ 5 

18 16,5 
10 15 
42 55 
+ 6 
...... 
18 19,6 
10 32 
42 3 ° 
+ 6 
11 7 
42 3 ° 
+ 6 
c 
• • rt • • 
1 8 12,2 
11 30 
42 10 
+ 7 
X 
• *.-*-» • • 
.... 
East 
Snow 
11 32 
42 00 
4 - 7 
. . <L> . . 
moderate 
falling 
" 33 
4 i 55 
+ 7 
<D 
0 5 
P.M. 
4 i 55 
+ 7 
18 12,8 
Max. westerly var. 
1 10 
2 7 
42 00 
42 00 
+ 6 
+ 5 
18 10,3 
18 8,7 
• * “ • • 
+ 38 
41 50 
+ 5 
18 8,2 
Squally 
Much 
3 57 
4 i 5 ° 
+ 5 
18 6,2 
drift 
5 00 
42 10 
+ 5 
1 7 5 9>7 
5 3 ° 
42 40 
+ 5 
18 1,7 
6 00 
42 40 
+ 5 
6 30 
■■ ; ! 
42 40 
+ 5 
17 5 6 >3 
7 00 
42 40 
+ 4 
1 
8 00 
42 40 
+ 45 
17 58 
10 2 
5 ° 3 o 
+ 4 
18 7 
Eastward 
Stars 
1 1 10 
50 30 
+ 4 
18 6,2 
Squally 
faintly 
11 55 
5 ° 3 ° 
+ 4 
18 11 
visible 
Apr. 13th 
1 7 
A, M. 
50 0 
+ 3 
18 14 
Easterly 
Cloudy 
2 5 
49 30 
+ 2 
18 14,5 
moderate 
3 6 
50 30 
+ 1 
18 1 6,7 
— 40 
5 i 30 
— 1 
18 18,5 
5 30 
6 00 
49 5 
48 30 
— 1 
18 22,8 
18 21,5 
Easterly 
Fine, 
Max. easterly var. 
6 30 
48 00 
— 1 
18 24,8 
Light 
clear. 
7 00 
47 00 
Zero 
• . . 
NE 
7 3 ° 
46 20 
Zero 
c 
• • ctf . • 
Squally 
8 00 
rG 
• *fh J • • 
18 28,5 
with drift 
■ 
9 00 
44 00 
+ 
. # QJ . . 
18 25,8 
9 5 ° 
43 5 ° 
+ °2 
0 
rG 
18 23,1 
10 10 
41 00 
Zero 
4 -» 
10 30 
> 
36 00 
Zero 
E-> 
18 21,2 
+ 11 10 
35 4 ° 
+ 1 

11 30 
36 5 
-j- I 

18 11,8 
1 5 
1 30 
P.M. 
37 00 
37 00 
+ I 
+ 1 

18 8,4 
1 7 5 8 >6 
Northerly 
Fresh 
Hazy 
Max. westerlyvar. 
