iron arising from its rotation. 
415 
Tables of the deviations of a magnetic needle, caused by the rapid rotation of 
a plate of iron^ observed during rotation, compared with the deviations 
due to the slow rotation of the plate, and permanent after the rotation had 
ceased. 
I'he iron plate, 18 inches in diameter, to the west of the eompass. 
Direction of the N. end of the needle when plate sta- 
tionary after slow rotation, and also while the plate 
was rapidly revolvine;. 
Angular velocity 
• 
* 
1 
Angular dis- 
of the plate, and 
Deviation due to the rota- J 
tancc of the 
points opposite 
Plate’s centre in N. lat. 
Plate’s centre in S. lat. 
tion of the plate’s upper I 
plate’s centre 
to the needle 
edge from N to S, when ; 
from 
the 
when plate sta- 
ohte’s centre was 
equator. 
tionary. 
Upper edge of the plate revolving. 
N to S 
1 
S to N 
N to S 
S to N 
in N. lat. 
in S. lat. ; 
i 
1 .80 
i 
0 / 
2 45W 
4 55 E 
0 / 
0 / 
“ / 
0 / 
p' 
14 25 E 
23 40 E 
6 40 E 
14 15 
8 loW 
2 05 E 
1 8 59W 
6 54 E 
o< 
8 rev. per sec. 
3 55W 
19 25 E 
14 30 
4 40W 
1 1 4oWi 9 35 E 
cj 
« 
L®'°" {.80 
2 55W 
6 30 E 
13 55 E 
24 40 E 
6 40 
14 50 
7 50W 
2 05 E 
1 8 4 sW 
! 6 49 E { 
3 
0 
r Slow \ f 
32 50W 
27 30W 
40 55 
33 20 
^ 2 2C 
1 3 15 i 
i 1 180 
27 40 
23 00 
42 25 
37 00 
• ^ 
20< 
j 8 rev. per sec. 
30 55 
24 35 
41 25 
32 40 
3 ‘o 
; 4 22 1 
L®'°" {.80 
32 50 
28 00 
27 35 
22 40 
ijo 40 
42 25 
33 35 
36 45 
1 2 34 
3 22 i 
3 
Q 
{ .80 
43 50 
40 30 
41 25 
38 00 
54 00 
53 05 
5 1 00 
50 40 
1 I H 
I 
I 21 
i i 
S0< 
8 rev. per sec. 
42 25 
39 ‘5 
53 30 
49 00 
I 35 
1 2 15 i 
s 
0 
vt; 
Slow 1 f 
1 1 '80 
43 45 
40 15 
41 25 
38 00 
54 10 
53 10 
5 1 20 
51 00 
[ I 09 
: I 15 1 
1 i 
"O 
c 
rt 
{.80 
52 30 
49 10 
51 00 
47 00 
59 25 
59 00 
57 20 
56 40 
1 0 55 
I 06 
70-i 
8 rev. per sec. 
51 05 
48 20 
57 40 
54 40 
I 23 
1 30 
Slow ^ ° 
52 30 
50 50 
59 40 
57 25 
[ 0 55 
! I 04 
jC 
1 1 80 
48 55 
46 55 
58 40 
56 40 
0 
fo, ( 0 
62 00 
60 20 
68 30 
66 40 
c 
d 
\ 180 
57 40 
56 00 
67 45 
66 lo 
1 0 50 
j 0 51 
90^ 
8 rev. per sec. 
60 35 
57 25 
66 5^ 
64 20 
^ 35 
I 17 1 
Ui 
4 -i 
c 
Slew \ f 
62 25 
58 00 
60 25 
56 20 
68 50 
67 55 
66 25 
66 15 
{oSS 
I 01 i 
) 
CO 
i 180 
72 25 
71 25 
75 25 
74 00 
0 35 ; 
(U 
63 10 
66 55 
76 00 
75 05 
^ 0 34 
1 10 J 
8 rev. per sec. 
70 20 
68 15 
74 40 
72 40 
I 02 
I 00 i 
P°"' {180 
72 35 
71 25 
75 35 
74 25 
1 0 38 
d 
0 
68 00 
66 40 
76 00 
75 00 
0 32 1 
{.80 
84 05 
84 10 
83 55 
83 30 
y 0 06 1 
0 1 1 
X 
80 50 
80 20 
85 00 
84 40 
1 0 
I30J 
8 rev. per sec. 
82 20 
81 00 
83 00 
81 45 
0 40 
0 37 
G 
1 
{ . 80 
84 20 
84 10 
84 00 
83 
1) 
1 
80 40 
80 15 
85 00 
84 55 
1 0 09 
0 14 
4 -* 
g 
0 
1 
{ 1 80 
86 20 
S2 15 
87 00 
83 45 
86 00 
87 40 
86 15 
88 05 
} 0 33 E 
0 loW 
I40J 
8 rev. per sec 
83 40 
85 00 
84 40 
85 15 
0 40 E 
0 18W i 
(U 
P 
1 
1 
{.So 
86 00 
82 40 
87 20 
. 83 55 
8s 40 
87 35 
86 20 
88 00 
} 0 39 E 
0 16W j 
P 
f 
75 20 
83 55 
76 00 
83 00 
} 7 05 E 
3 18 
^ 1 
i6o<^ 
1 1 80 
54 00 
73 45 
78 15 
84 25 
8 rev. per sec. 
57 55 
78 20 
69 40 
80 30 
10 12 E 
5 25 
Slow i ° 
76 to 
83 40 
76 05 
82 00 
) 1 80 
_ ^ 
53 20 
72 50 
78 10 
84 20 
1 6 45 
3 01 
