Horizontal Component of Magnetic Force. 



229 



Variations op the Diurnal Ranges of Magnetic Declination with 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 



27 3 ... 7 New Moon, 



4 11 ... 8 First Quarter, 



12 18 ... 7 Full Moon, 



9-70 

 10-41 

 11-01 

 10-04 



From these means the maximum would appear to occur in the First Quarter, and the minimum in the 

 Third Quarter. 



Variations op the Diurnal Range op 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 or tne iiiquator nortnwaras, 



25 3 greatest north declination. 



lu-uo 



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 op 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. 





C I 



I . 



January. 



February. 



March. 



April. 



May. 



June. 



July. 



August. 



September. 



October. 



November. 



December. 





0-00 



0-00 



0-00 



0-00 



. O'OO 



0-00 



0-00 



0-00 



0-no 



0-00 



O'OO 



o-oo 





[ ] 



1645 



1808 



1804 



2068 



2722 



2288 



2766 



3093 



[2982] 



3572 



3695 





1353 



1780 



1952 



[1540] 



2033 



3097 



[2722] 



2537 



3200 



2617 



3851 



3695 





1531 



1761 



1973 



1533 



2418 



2569 



2765 



3476 



[2904] 



2862 



3204 



[3911] 





1589 



2386 



1991 



1420 



2455 



[2791] 



2508 



3025 



2590 



3342 



3919 



4059 





1649 



[1928] 



[1670] 



1613 



2323 



2566 



2499 



2638 



2449 



2863 



[3487] 



3969 





1766 



2003 



1736 



0848 



1807 



2722 



2443 



[2745] 



2949 



2728 



3600 



3926 





1955 



1820 



1114 



1097 



[1995] 



3067 



2814 



2870 



2638 



2899 



3294 



4318 





[1853] 



1815 



1255 



1729 



1037 



2265 



2360 



2478 



2759 



[2923] 



3056 



3688 





2148 



1379 



1636 



[1320] 



1664 



2432 



[2557] 



1984 



2752 



2833 





4670 





1863 



1718 



1603 



1185 



2685 



3352 



2675 



2679 



[2794] 



2977 





[4122] 





1741 



1574 



1708 



1276 



2197 



[2622] 



2630 



2626 



2771 



3241 



3201 



4059 





1695 



[1570] 



[1456] 



1784 



2087 



2679 



2425 



2754 



2958 



3321 



r3307] 



3943 





1809 



1778 



1079 



1620 



2225 



2293 



2775 



[2644] 



2886 



3353 



3408 



4055 





1695 



1247 



1220 



1594 



[2364] 



2711 



2667 



2470 



3342 



3337 



3340 



4113 





[1894] 



1726 



1493 



1365 



2900 



2511 



2944 



2524 



3289 



[3291] 



3343 



4265 





2358 



1907 



1029 



[1693] 



2270 



2415 



[2762] 



2812 



3398 



3655 



3410 



4420 





1951 



1941 



1254 



1871 



2504 



2598 



^701 



2944 



[3249] 



2747 



4005 



[4326] 



t 



1855 



1835 



1667 



1919 



2519 



[2735] 



2652 



2827 



3613 



3335 



3816 



4238 



u 



lG. and mi 



/r. OBS. 1: 



343. 

















3 M 





