i64f Lieut. Foster’s observations on the diurnal changes 
North end of Needle to the S 85 0 W. The line of minimum daily variation. 
Date. 
Blean 
Time of 
Obser- 
vation. 
A. M. 
or 
P. M. 
Reading of 
north end of 
Needle. 
Temp. 
Faliren 1 . 
Direction of 
north end of 
needle during 
westerly daily 
variation. 
Time that a ho- 
rizontal needle 
took to make 
60 vibrations. 
Winds. 
Weather. 
Remarks, &c. 
Instr. 
1825 . 
h. m. 
O 
m. s. 
April 4th 
+ 9 10 
A. M. 
S 82 00 W 
—21 
00 
CM 
9 5 2 
83 40 
—21 
03 
10 15 
84 50 
—21 
18 1,5 
11 s 
85 30 
21 
18 1,5 
0 S 
P. M. 
85 40 
— I 9 
<L> 
0 *pC! e * 
18 2 
« • « « 
« • 9 • 
Max. westerly var. 
- 1 10 
91 00 
— *8 
+-> 
• • 0 # * 
17 43>5 
1 20 
91 00 
— 18 
h 
1 50 
89 IO 
—18 
2 10 
89 OO 
—18 
5 7 45 >4 
• • • • 
• 8 a » 
Max. easterly var. 
2 45 
89 OO 
—18 
3 8 
86 50 
—18 
1 7 58,1 
3 25 
86 50 
—17 
Easterly 
Clear and 
3 54 
86 10 
—17 
e e 9 a • 0 
18 2,7 
light 
fine. 
5 00 
86 10 
—18 
18 00 
5 30 
86 30 
—18 
6 00 
86 30 
—I 9 l 
• ••••• 
>7 55 
7 00 
86 30 
—20 
J 7 54 
9 00 
86 30 
■ — 22 
l 7 54 
9 55 
86 30 
—23 
10 15 
86 25 
—23 
• • 0 © • • 
17 56,2 
1 1 00 
86 25 
—23 
11 16 
86 25 
—23 
*7 5 7 >4 
11 50 
86 00 
—23 
18 0,3 
April 5 th 
1 7 
A. M. 
86 00 
—24 
18 2,3 
2 5 
85 40 
—24 
18 2,8 
3 0 
85 30 
—25 
• ••••• 
18 3»3 
Easterly 
Clear and 
4 2 
85 OO 
—25 
18 7>5 
light 
fine. 
5 3 ° 
85 OO 
—25 
17 58 
North end of Needle to the N 85° E. 
Both magnets 
were placed to the south of the compass ; the distance from the centre of the box. 
to the nearest end of the magnet, attracting the north end of the needle, was 
18,98 inches, and to the 
nearest end of the other, attracting the south end of the needle, 
27 inches. The needle now made 
1 vibration in 9,5 seconds, the directive force being reduced in the ratio of 0 
,35 to 1 nearly. 
April 5th 
6 00 
A. M. 
N 85 0 E 
—25 
17 59*5 
Easterly 
Clear and 
O rising ENE. 
7 00 
85 10 
—25 
1 8 6,2 
light 
fine. 
(true.) 
7 30 
84 30 
—25 
18 i,s 
8 56 
84 OO 
— 22 
• . . 
18 1,8 
9 *5 
83 50 
— 22! 
• • 03 • • 
18 1 
9 3 ° 
83 20 
- 2 IJ 
fit* 
Max.wester/y var. 
10 00 
82 30 
— 21 J 
JZ 
• • 60* * 
18 0,2 
10 15 
84 30 
21 
’£ 
10 50 
86 00 
20 
<L> 
pH 
1 1 00 
8S 30 
20 
4 — » 
• • O * * 
18 6,4 
11 30 
84 30 
— 19 
b 
