Horizontal Component of Magnetic Force. 



233 



Variations op the Horizontal Component of Magnetic Force, with reference to the 



Moon's Declination. 



Means of Groups. 



27 days to 1 day, Moon farthest North, 0-000232 



2 5 ... 0000138 



6 8 ... 0000134 



9 12 ... 0-000207 



13 days to 15 days, Moon farthest South, 0-000218 



16 19 ... 0000165 



20 22 ... 0-000213 



23 26 ... 0-000187 



From these means we may conclude that there are maxima when the moonhas its greatest north and south 

 declination, and minima when its declination is zero ; the principal minimum occurs when the moon is on the 

 equator moving southwards. 



Variations of the Horizontal Component of Magnetic Force, with reference to the 



Moon's Distance from the Earth. 



Means of Groups. 



6 days after Apogee to 6 days before Perigee, 0000322 

 5 days to 2 days before Perigee, . . . 0-000145 



1 day before to 1 day after Perigee, . . 0-000210 



2 days to 5 days after Perigee, . . . 0-000261 



6 days after Perigee to 6 days before Apogee, 0-000191 

 5 days to 2 days before Apogee, . . . 0-000205 



1 day before to 1 day after Apogee, . . 0'000235 



2 days to 5 days after Apogee, . . . 0-000240 



TABLE X. — Means of the Bifilar Magnetometer Readings Corrected for Temperature, at the 



Observation Hours for each Month in 1843. 



Month. 



181-. 



SOI-. 



22\ 



23h. 



Oh. 



2h_ 



4h. 



6t. 



St. 



101". 





Sc. DiT. 



Sc. Div. 



Sc.Div 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



So. Div. 



January 



538-10 



537-95 



533-71 





534-11 



538-80 



540-62 



538-19 



537-11 



537-41 



February 



535-84 



539-04 



533-72 





534-93 



538-23 



540-14 



537-43 



538-34 



537-39 



March 



534-90 



534-22 



528-48 





528-07 



535-96 



540-36 



540-54 



538-30 



537-34 



April 



May 



534-53 



533-37 



524-37 





525-56 



536-19 



543-66 



548-25 



542-26 



536-90 



496-79 



492-82 



486-56 





489-30 



501-94 



506-84 



512-85 



512-56 



501-77 



June 



500-47 



495-70 



48800 





491-42 



502-11 



508-64 



512-19 



515-87 



510-96 



July 



497-55 



495-32 



486-07 





488-08 



499-48 



512-98 



515-88 



513-74 



506-85 



August 



498-64 



494-37 



487-41 





491-91 



505-11 



512-13 



514-71 



512-69 



511-20 



September 



505-50 



500-25 



491-77 





496-61 



505-57 



512-57 



509-50 



510-72 



509-48 



October 



508-03 



504-51 



495-66 





497-44 



508-25 



512-18 



512-64 



512-31 



511-17 



f 



510-60 



509-00 



503-19 



501-43 



503-77 



512-41 



515-16 



516-06 



513-70 



509-29 



























513-69 



513-08 



508-73 



508-45 



51006 



513-66 



51404 



514-41 



512-09 



512-10 



December 



518-08 



518-14 



514-01 



513-52 



513-64 



514-38 



516-53 



514-82 



514-48 



512-97 



Table X. is intended chiefly as a key for comparing the tabular observations. The cross lines indicate 

 breaks in the series from new adjustments, which will be found alluded to after Table VIII. 



MAG. AND MET. OBS. 1843. 



3 N 



