88 MR. BROOKE ON THE AUTOMATIC REGISTRATION OF MAGNETOMETERS, 
simultaneously at the Royal Observatory ; the result is therefore open to the objection 
of a possible difference in the changes of horizontal force at the two places. But it 
appears from a comparison of several photographic registers obtained simultaneously 
at Greenwich and in Keppel Street, some of which include periods of considerable 
disturbance, that a difference in the simultaneous changes of horizontal force in 
these two localities is very rarely perceptible. 
The annexed Table contains the numerical observations from which the temperature 
coefficient of the bar C.B. VIII. has been determined. The scale-readings are taken 
C.B. VIII. 
Times of 
observa- 
tion. 
March, 
1849. 
Scale- 
readings of 
Royal Ob- 
servatory 
registers. 
Differ- 
ences. 
Corre- 
sponding 
values on 
my scale. 
Axl-115. 
Differ- 
ences of 
my scale- 
readings. 
Scale- 
readings 
of my re- 
gisters. 
Tempe- 
ratures. 
Fahk. 
Differ- 
ences of 
tempera- 
ture. 
Mean 
tempera- 
tures. 
Reduced 
scale- 
readings. 
B + C. 
D2. 
DxR. 
DxM. 
d h m 
0 22 5 
30 
23 0 
30 
1 0 0 
30 
1 0 
2 4 
627 
630 
630 
628 
630 
626 
610 
610 
A. 
3 
0 
- 2 
2 
— 4 
-16 
0 
B. 
3 
0 
— 2 
2 
— 5 
— 18 
0 
c. 
80 
74 
54 
42 
49 
51 
89 
55 
135 
209 
263 
305 
354 
405 
494 
100-5 
95-2 
90*5 
87-3 
84-2 
81-2 
78-8 
73-4 
D. 
5-3 
4- 7 
3-2 
3-1 
3-0 
2-4 
5- 4 
M. 
97-9 
92-8 
88-9 
85-8 
82-7 
80-0 
76-1 
R. 
83 
74 
52 
44 
44 
33 
89 
2809 
2209 
1024 
961 
900 
576 
2916 
4399 
3478 
1664 
1364 
1320 
792 
4806 
51887 
43616 
28448 
26598 
24810 
19200 
41094 
22 0 
30 
23 0 
30 
2 0 0 
1 0 
2 0 
3 0 
4 0 
5 10 
7 0 
11 38 
20 19 
635 
639 
644 
668 
660 
652 
653 
646 
646 
621 
617 
608 
601 + 16 
4 
5 
24 
— 8 
— 8 
1 
— 7 
6 
-25 
— 4 
— 9 
9 
5 
6 
28 
- 9 
- 9 
1 
- 8 
0 
-29 
— 5 
— 10 
10 
78 
58 
14 
58 
83 
53 
54 
24 
57 
42 
44 
21 
30 
108 
166 
180 
238 
321 
374 
428 
452 
509 
551 
595 
616 
92-8 
88-4 
85-5 
83-3 
80-4 
75-8 
72-1 
68-9 
67-2 
65-3 
62-6 
60-0 
58-0 
4,4 
2-9 
2-2 
2- 9 
4-6 
3- 7 
3-2 
1-7 
1- 9 
2- 7 
2-6 
2-0 
90-6 
86-9 
84-4 
81-8 
78-1 
74-0 
70-5 
68-0 
66-2 
64-0 
61-3 
59-0 
83 
63 
42 
49 
74 
55 
46 
24 
28 
37 
34 
31 
1936 
841 
484 
841 
2116 
1369 
1024 
289 
361 
729 
676 
400 
3652 
1827 
924 
1421 
3404 
2035 
1472 
408 
532 
999 
884 
620 
39864 
25201 
18568 
23722 
35926 
27380 
22560 
11560 
12578 
17280 
15938 
11800 
8 21 8 
34 
22 8 
48 
23 38 
9 0 3 
1 0 
2 25 
3 0 
30 
4 0 
5 7 
6 0 
40 
7 37 
9 9 
10 44 
21 15 
563 
572 
574 
596 
584 
556 
582 
562 
547 
560 
569 
573 
573 
576 
565 
568 
557 + 2 
580 + 12 
9 
2 
22 
— 12 
—28 
26 
— 20 
— 15 
13 
9 
4 
0 
3 
— 11 
3 
- 9 
33 
10 
2 
25 
— 14 
— 32 
30 
-23 
-17 
15 
10 
4 
0 
3 
— 13 
3 
— 10 
38 
74 
90 
58 
95 
63 
40 
103 
51 
16 
19 
30 
38 
24 
51 
15 
22 
23 
18 
92 
182 
240 
335 
398 
438 
541 
592 
608 
627 
657 
695 
719 
770 
785 
807 
830 
103-0 
98-5 
93-2 
88-5 
83-9 
81-8 
77-4 
72-6 
70-7 
69*4 
68-2 
66-7 
65-0 
63-7 
62-1 
60-8 
59-6 
55-2 
4- 5 
5- 3 
4-7 
4-6 
2-1 
4-4 
4-8 
1*9 
1-3 
1-2 
1-5 
1-7 
1-3 
1-6 
1-3 
1-2 
4-4 
100-8 
95-9 
90-8 
86-2 
82-8 
79-6 
75-0 
717 
70-1 
68-8 
67-5 
65- 9 
64-4 
62-9 
61-4 
66- 2 
57-4 
84 
92 
83 
81 
31 
70 
80 
34 
31 
29 
34 
38 
27 
38 
18 
12 
61 
2025 
2809 
2209 
2116 
441 
1936 
2304 
361 
169 
144 
225 
289 
169 
256 
169 
144 
1936 
3780 
4876 
3901 
3726 
651 
3080 
3840 
646 
403 
348 
510 
646 
351 
608 
234 
144 
2684 
45.360 
50827 
42676 
39652 
17388 
,35024 
.36000 
13623 
9113 
8256 
10125 
11203 
8372 
10064 
7982 
7224 
25256 
