AND METEOROLOGICAL INSTRUMENTS, BY PHOTOGRAPHY. 89 
C.B. VIII. (Continued.) 
Times of 
observa- 
tion. 
March, 
1849. 
Scale- 
readings of 
Royal Ob- 
servatory 
registers. 
Differ- 
ences. 
Corre- 
sponding 
values on 
my scale. 
Ax I'llo. 
Diifer- 
ences of 
my scale- 
readings. 
Scale- 
readings 
of my re- 
gisters. 
Tempe- 
ratures. 
Fahr. 
Differ- 
ences of 
tempera- 
ture. 
Mean 
tempera- 
tures. 
Reduced 
scale- 
readings. 
B-fC. 
D 2 . 
DxR. 
DxM. 
d h m 
10 1 42 
2 0 
2 30 
3 0 
30 
4 0 
43 
5 38 
6 0 
7 13 
8 13 
9 9 
43 
11 28 
600 
597 
589 
572 
569 
569 
565 
567 
565 
557 
562 
571 
565 
565 
A. 
3 
8 
17 
3 
0 
4 
— 2 
2 
8 
— 5 
- 9 
6 
0 
B. 
3 
9 
20 
3 
0 
5 
- 2 
2 
9 
- 6 
— 10 
7 
0 
C. 
5 
6 
— 1 
18 
20 
13 
22 
9 
13 
27 
28 
1 
19 
195 
190 
184 
185 
167 
147 
134 
112 
103 
90 
63 
35 
34 
15 
33- 5 
34- 1 
35- 2 
36- 8 
38-7 
40- 4 
41- 7 
42- 8 
43- 4 
44- 8 
46- 1 
47- 0 
47-5 
48*7 
D. 
0-6 
1*1 
1-6 
1-9 
1-7 
1-3 
M 
0-6 
1-4 
1-3 
0-9 
0- 5 
1- 2 
M. 
33- 8 
34- 6 
36- 0 
37- 7 
39-5 
4M 
42-3 
43*1 
44*1 
45-5 
46*6 
47- 3 
48- 2 
R. 
8 
15 
19 
21 
20 
18 
20 
11 
22 
21 
18 
8 
19 
36 
121 
256 
361 
289 
169 
121 
36 
196 
169 
81 
25 
144 
48 
165 
304 
399 
340 
234 
220 
66 
308 
273 
162 
40 
228 
2028 
3806 
5760 
7163 
6715 
5343 
4653 
2586 
6174 
5915 
4194 
2365 
5784 
11 6 40 
7 30 
8 8 
9 7 
10 21 
59 
550 
549 
551 
547 
547 
547 
— 1 
2 
— 4 
0 
0 
— 1 
2 
— 5 
0 
0 
36 
19 
31 
29 
12 
92 
128 
147 
178 
207 
219 
69-8 
67-5 
65*8 
63-8 
61-7 
60-8 
2-3 
1- 7 
2- 0 
2-1 
0-9 
68*6 
66-7 
64-8 
62-7 
61*2 
35 
21 
26 
29 
12 
529 
289 
400 
441 
81 
805 
357 
520 
601 
108 
15678 
11339 
12960 
13167 
5508 
11 23 45 
58 
12 0 20 
45 
1 0 
48 
2 18 
3 0 
4 0 
614 
612 
608 
606 
596 
579 
569 
579 
566 
2 
4 
2 
10 
17 
10 
— 10 
13 
2 
5 
2 
11 
20 
11 
— 11 
15 
9 
14 
17 
3 
17 
8 
33 
13 
654 
645 
631 
614 
611 
594 
586 
553 
540 
33-2 
33-9 
35-4 
36*8 
37-8 
40-7 
42- 0 
43- 5 
45*4 
0- 7 
1- 5 
1- 4 
1-0 
2- 9 
1-3 
1-5 
1-9 
33- 6 
34- 6 
36- 1 
37- 3 
39-2 
41-4 
42*8 
44.4 
11 
19 
19 
14 
37 
19 
22 
28 
49 
225 
196 
100 
841 
169 
225 
361 
77 
285 
266 
140 
1073 
247 
330 
532 
2352 
5190 
5084 
3730 
11368 
5382 
6420 
8436 
on a scale having- 100 divisions in an inch. The differences of the scale-readings of 
the Royal Observatory registers are reduced to the scale of the observed magnet by 
multiplying them by the ratio of the scale coefficients : this ratio is expressed by 
TH5*. The reduced scale-readings, R, are the sums of the readings B and C, 
because the variation is represented in opposite directions on the two registers. 
These quantities being arranged in five groups according to the temperatures M, 
and the mean values obtained by the above formulse, the five following equations 
result : — 
x-f 7-2j/=: 13-42 
x-1-2 1-73/ =14-54 
J7-f-34-63/= 15-55 
x-l-49-5y= 16-50 
x -|-62-83/= 17-20 
r-0-10 
-fO-02 
residual errors <( +015 
I +0-08 
L — 0-12 
* In the very few instances in which it appeared necessary, a correction has been applied to the Greenwich 
scale-readings for observed changes of temperature. 
MDCCCL. 
N 
