688 
SIR G. B. AIRY ON RESULTS DEDUCED FROM THE MEASURES 
Monthly Means of Daily Range of Horizontal Magnetic Force at Greenwich 
Mean Daily Eange of Horizontal Force in the Direction of Astronomical Meridian. 
Year. 
Month. 
Eange of 
Meridian 
Force. 
In Greenwich Mean Solar 
Time. 
Approximate Hour of 
Minimum 
Meridian 
Force. 
Maximum 
Meridian 
Force. 
h. m. 
h. m. 
I 860 J 
June. . . 
July . . . 
•0025 
•0024 
23 30 
22 10 
11 0 
7 0 
1866 
June . . . 
J uly . . 
•0020 
•0022 
0 0 
22 10 
7 30 
7 0 
1867^ 
June. . . 
July . . . 
•0024 
•0022 
23 0 
23 0 
7 0 
9 0 
1868-j 
June. . . 
July . . . 
•0025 
•0026 
23 0 
0 0 
7 0 
8 0 
OO 
ca 
CO 
June. . . 
July . . . 
•0036 
•0033 
23 0 
22 30 
l 0 
7 0 
0 
r— 
00 
June. . . 
July . . . 
•0041 
•0037 
23 0 
23 0 
7 0 
7 0 
1871-j 
June. . . 
July . . . 
•0035 
•0036 
0 0 
23 40 
7 0 
7 0 
1872^ 
1 
June. . . 
July . . . 
•0037 
•0031 
23 0 
0 10 
7 0 
7 0 
OO 
CO 
June. . . 
July . . . 
•0027 
•0031 
23 30 
22 30 
7 10 
6 50 
i- 
OO 
June. . . 
July . . . 
•0024 
•0023 
23 0 
23 0 
6 20 
7 30 
1875 j 
June . . . 
July . . . 
•0019 
•0021 
23 0 
23 0 
7 20 
7 30 
r 
1876 < 
June . . . 
July . . . 
•0018 
•0020 
22 30 
23 30 
8 0 
7 0 
Month. 
Range of 
Meridian 
Force. 
In Greenwich Mean Solar 
Time. 
Approximate Hour of 
Minimum 
Meridian 
Force. 
Maximum 
Meridian 
Force. 
h. 
m. 
h. 
m. 
January . . 
Obser 
vations 
inter 
rupted. 
December . . 
•0009 
23 
10 
18 
0 
Janaary . . 
•0011 
0 
0 
19 
0 
December . . 
•0008 
23 
0 
18 
0 
January . . 
•0010 
23 
20 
8 
0 
December . . 
•0009 
23 
0 
18 
0 
J anuary . . 
•0007 
0 
0 
19 
0 
December . . 
•0010 
23 
20 
18 
0 
January . . 
•0014 
23 
50 
19 
0 
December . . 
•0012 
23 
0 
17 
0 
J anuary . . 
•0016 
23 
40 
17 
0 
December . . 
•0017 
0 
30 
18 
0 
J anuary . . 
•0019 
0 
0 
11 
0 
December . . 
■0017 
23 
30 
18 
0 
January . . 
•0017 
0 
0 
18 
0 
December . . 
•0010 
0 
0 
18 
0 
January . . 
•0017 
0 
0 
18 
0 
December . . 
•0008 
23 
20 
17 
30 
J anuary . . 
•0011 
0 
0 
18 
0 
December . . 
•0007 
0 
0 
18 
30 
January . . 
•0007 
23 
0 
18 
30 
December . . 
•0008 
23 
20 
20 
0 
J anuary . . 
•0009 
0 
0 
19 
0 
December . . 
•0006 
0 
0 
19 
0 
