Hokizontal Component of Magnetic Force. 
229 
Variations of the Diurnal Ranges of Magnetic Declination avith reference to the 
Relative Positions of the Sun, Moon, and Earth, as indicated by the Moon's Age. 
The partial means are very irregular, their general aspect when projected is that of a maximum near the 
time of new moon, and a minimum near the time of full moon ; in groups, the results are as follow : — 
19 days to 26 days, 
8 days including 
the Third Quarter, mean 
9-70 
27 3 ... 
7 
. 10-41 
4 11 ... 
8 
11-01 
12 18 ... 
7 
Full Moon, 
1004 
From these means the maximum would appear to occur in the First Quarter, and the minimum in the 
Third Quarter. 
Variations of the Diurnal Range of the Magnetic Declination with reference to the 
Moon's Declination. 
In the partial means there is an appearance of a secondary maximum at the moon's greatest south 
declination, but this disappears in the following means : — 
4 days to 10 days, including the moon's passage of the Equator southwards, mean 10-11 
11 17 greatest south declination, 9-64 
18 24 passage of the Equator northwards, 10-05 
25 3 greatest north declination, 11-27 
Or, the diurnal range of the magnetic declination is a maximum when the moon has its greatest north 
declination, and it is a minimum at the time of the moon's greatest south declination. 
Horizontal Component of Magnetic Force. 
TABLE VIII. — Mean Values of the Variations of the Horizontal Component of Magnetic Force, the 
whole Horizontal Component being Unity, for each Civil Day, as deduced from the Nine Daily 
Observations, for each Week, and for each Month, in the Year 1843- 
Civil 
Day. 
January. 
February. 
March. 
April. 
May. 
June. 
July. 
August. 
September. 
October. 
November. 
December. 
0-00 
0-00 
0-00 
o-oo 
0-00 
0-00 
0-00 
0-00 
0-00 
0-00 
000 
0-00 
1 
[ ] 
1645 
1808 
1804 
2068 
2722 
2288 
2766 
3093 
[2982] 
3572 
3695 
2 
1353 
1780 
1952 
[1540] 
2033 
3097 
[2722] 
2537 
3200 
2617 
3851 
3695 
3 
1531 
1761 
1973 
1533 
2418 
2569 
2765 
3476 
[2904] 
2862 
3204 
[3911] 
4 
1589 
2386 
1991 
1420 
2455 
[2791] 
2508 
3025 
2590 
3342 
3919 
4059 
5 
1649 
[1928] 
[1670] 
1613 
2323 
2566 
2499 
2638 
2449 
2863 
[3487] 
3969 
6 
1766 
2003 
1736 
0848 
1807 
2722 
2443 
[2745] 
2949 
2728 
3600 
3926 
7 
1955 
1820 
1114 
1097 
[1995] 
3067 
2814 
2870 
2638 
2899 
3294 
4318 
8 
[1853] 
1815 
1255 
1729 
1037 
2265 
2360 
2478 
2759 
[2923] 
3056 
3688 
9 
2148 
1379 
1636 
[1320] 
1664 
2432 
[2557] 
1984 
2752 
2833 
4670 
10 
1863 
1718 
1603 
1185 
2685 
3352 
2675 
2679 
[2794] 
2977 
[4122] 
11 
1741 
1574 
1708 
1276 
2197 
[2622] 
2630 
2626 
2771 
3241 
3201 
4059 
12 
1695 
[1570] 
[1456] 
1784 
2087 
2679 
2425 
2754 
2958 
3321 
T3307] 
3943 
13 
1809 
1778 
1079 
1620 
2225 
2293 
2775 
[2644] 
2886 
3353 
3408 
4055 
14 
1695 
1247 
1220 
1594 
[2364] 
2711 
2667 
2470 
3342 
3337 
3340 
4113 
15 
[1894] 
1726 
1493 
1365 
2900 
2511 
2944 
2524 
3289 
[3291] 
3343 
4265 
16 
2358 
1907 
1029 
[1693] 
2270 
2415 
[2762] ' 
2812 
3398 
3655 
3410 
4420 
17 
1951 
1941 
1254 
1871 
2504 
2598 
2701 
2944 
[3249] 
2747 
4005 
[4326] 
18 
1855 
1835 
1667 
1919 
2519 
[2735] 
2652 
2827 
3613 
3335 
3816 
4238 
MA.G. AND MET. OBS. 1843. 
