148 
Lieut . Foster’s observations on the diurnal changes 
North end of Needle to the S. W. 
The distance of the nearest ends of the magnets from the centre of the compass 27 inches ; the axis 
of each magnet was inclined to the magnetic meridian, and the needle under their influence made one 
vibration in seconds ; so that the directive force now, was to the undiminished force as 0,20 to 1. 
Date. 
Mean 
Time of 
Obser- 
vation. 
A. M. 
or 
P.M. 
1825 . 
h. 
m. 
Mar. 2d 
I 
00 
A. M. 
I 
3° 
2 
00 
2 
3 ° 
3 
20 
4 
00 
5 
6 
6 
8 
7 
6 
7 
54 
9 
00 
9 
30 
10 
00 
10 
3 ° 
II 
00 
II 
30 
0 
P. M. 
0 
35 
I 
00 
I 
30 
+ I 
40 
2 
00 
2 
30 
3 
5 
3 
55 
5 
00 
5 
40 
6 
*5 
7 
00 
7 
40 
8 
00 
9 
00 
H 
00 
Mid 1 . 
Mar. 3d 
1 
10 
A- M. 
2 
6 
3 
0 
3 
5 ° 
5 
10 
5 
40 
Reading of 
north end of 
Needle. 
Temp. 
Fahren 
Instr. 
Direction of 
north end of 
needle during 
westerly daily 
variation. 
Time that a ho- 
rizontal needle 
took to make 
60 vibrations. 
Winds. 
0 / 
O 
42 00W 
—29 
41 50 
—30 
4 1 3 ° 
—293 
40 50 
— 3 ° 
40 20 
—30 
39 5 ° 
HlC* 
0 
CO 
1 
40 00 
—31 
40 20 
—31 
41 20 
’ 3 1 
4 i 30 
—32 
43 20 
—32 
44 00 
—32 
45 3 o 
—32 
46 10 
— 3 i 
46 20 
— 3 ° 
45 5 ° 
—30 
45 3 ° 
—30 
45 3 ° 
—30 
45 3 o 
—30 
49 3 o 
—30 
50 15 
—30 
50 10 
— 29I 
50 00 
—292 
48 20 
—29 
47 4 ° 
—29 
44 3 o 
—295 
44 20 
— 291 
44 00 
—292 
43 55 
— 3 ° 
44 00 
— 3 ° 
44 00 
— 3 ° 
44 00 
“ 3°5 
43 40 
— 3 1 
43 00 
— 3 1 
42 30 
— 3 i 
40 20 
— 3 1 
39 5 ° 
— 3 » 
38 3 ° 
— 3 i 
40 40 
— 3 1 
41 20 
— 3 i 
m. s. 
l 7 5 6 >3 
17 58 
1 7 59> 1 
*8 9>3 
18 3 
18 3 
18 1,8 
18 1 
18 00,5 
1 7 53*2 
1 7 5 3 >6 
18 2,2 
17 58,8 
17 48,5 
1 7 4 6 >5 
17 49 
*7 53 * 6 . 
1 7 5 2 >S 
17 54>4 
17 52 ,7 
i 7 53>5 
17 54>2 
17 54 
1 7 57 >0 
17 59 > 6 
i >3 
8,5 
57,4 
18 
18 
17 
Northerly 
Light 
Calm 
Easterly- 
Light 
Easterly 
Light 
Easterly 
Light 
Squally 
Weather. 
Remarks, &c. 
Clear and 
Fine 
Clear and 
Fine 
Max. westerly 
variation. 
At i h 25'P.M. 
the needle com- 
menced moving 
rapidly to the 
westward, inten- 
sity at that time 
increasing. 
Very 
Hazy 
Clearer 
Clear and 
Fine 
Clear and 
Fine 
Max. easterly 
variation. 
Hazy 
