HorizontTAL CoMponENT OF MAGNETIC FoRcE. 233 
VARIATIONS OF THE HORIZONTAL COMPONENT OF MAGNETIC FORCE, WITH REFERENCE TO THE 
Moon’s DECLINATION. 
Means of Groups. 
me gee to 1 day, Moon farthest North, 0-000232 13 days to 15 pe Moon farthest South, 0:000218 
Sd 0-000138 GT. eee 19 , 0:000165 
noses (nae 0:000134 2D. aeoan 22s 8 0:000213 
D) aeheee hee. 0:000207 PB Ene peer Sri 0:000187 
From these means we may conclude that there are maaima when the moon has 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 T0 THE 
Moon’s DISTANCE FROM THE EARTH. 
Means of Groups. 
6 days after Apogee to 6 days before Perigee, 0:000322 | 6 days after Perigee to 6 days before Apogee, 0:000191 
5 days to 2 days before Perigee, . . . 0:000145 | 5 days to 2 days before Apogee, . . . 0:000205 
1 day before to 1 day after Perigee, . . 0:000210 | 1 day before to 1 day after Apogee, . . 0:000235 
2 days to 5 days after Perigee, . . . 0:000261 | 2 days to 5 days after Apogee, . . . 0:000240 
TABLE X.—Means of the Bifilar Maonetometer Readings Corrected for Temperature, at the 
Observation Hours for each Month in 1843. 
Month. 18, 20%, 22h, 23h, 0b, 2h, 4h, 6b. 8h. 102. 
Se. Diy. Sc. Div. Se. Div Sc. Diy. Se. Div. Se. Div. Sc. Div. Se. Div. Se. Div. Se. Diy. 
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 i 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 534-53 | 533-37 | 524-37 525-56 | 536-19 | 543-66 | 548-25 | 542-26 | 536-90 
May 496-79 | 492-82 | 486-56 489-30 | 501-94 | 506-84 | 512-85 | 512.56 | 501-77 
June 500-47 | 495-70 | 488-00 491-42 | 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 
510-60 | 509-00 | 503-19 | 501-43 | 503-77 | 512-41 | 515-16 | 516-06 | 513-70 | 509-29 
Novenber| J $$$) J J | | | 
513-69 | 513-08 | 508-73 | 508-45 | 510-06 | 513-66 | 514-04 | 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. oss, 1843. 3.N 
