232 ABSTRACTS OF THE MAKERSTOUN OpsERVATIONS, 1843. 
TABLE IX.—Mean Variations of the Horizontal Component of Magnetic Force, after eliminating 
the Secular Change, with reference to the Moon’s Age, Declination, and Distance from the 
Earth, for 1843. 
Variations Variations || After | Variations | After | Variations |} Before | Variations | Before | Variations 
Moon’s| of Hori- | Moon’s| of Hori- Moon of Hori- Moon of Hori- and of Hori- and of Hori- 
zontal Age. zontal farthest zontal farthest zontal after zontal after zontal 
Component. Component. || North. | Component.} North. | Component. || Perigee.| Component. | Apogee.| Component. 
0-000 Day. 0:000 Day. 0-000 Day. 0-000 Day. 0-000 Day. 0-000 
000 0 288 0 263 14 224 7 328 7 145 
199 1 213 1 211 15 182 6 256 6 061 
117 2 322 2 292 16 103 5 249 5 232 
245 3 260 3 246 17 119 4 000 4 173 
169 BS 288 4 013 18 204 3 091 3 225 
246 5 311 5 000 19 234 2 239 2 191 
299 6 242 6 034 20 274 1 192 1 242 ' 
300 7 115 uf 126 21 138 P 197 A 144 ; 
196 8 178 8 243 22 228 1 242 1 320 ), 
328 9 083 9 188 23 191 2 251 2 256 R 
251 10 038 10 089 24 182 3 219 3 253 > 
313 11 090 11 329 25 224 4 263 4 238 “ 
350 12 125 12 223 26 151 5 311 5 250 ; 
359 13 043 13 247 27 223 6 338 6 364 
229 14 173 if 222 7 342 ¥ 
Table IX. was formed from Table VIII. in the manner indicated for the magnetic declination, Table II. 
VARIATIONS OF THE HorizoNTAL COMPONENT OF MAGNETIC FORCE, WITH REFERENCE TO THE 
RELATIVE POSITIONS OF THE SuN, Moon, AND EARTH, AS INDICATED BY THE Moon’s AGE. 
The partial means in the first portion of Table IX. shew distinctly what is more distinctly evident in the 
following means, namely, the maximum about the period of new moon, and the minimum at the period of full 
moon :— 
Means of Groups. 
14 days to 16 days, Full Moon, 0:000124 29 days to 1 day, New Moon, 0:000243 
Ip bested 20h. 0:000194 Drache yee 0-000295 
Dil pasiga® Bie) Gos 0:000278 (HY Bacau By nae 0:000154 
OA on en 28h. 0-000318 Oe eels LS. 0:000074 
It should be remarked that there is a secondary minimum shewn in these means at the time of new moon; 
this would not have been seen so distinctly, or at all, had larger groups been taken. As this minimum is 
also shewn, and nearly to the same extent in the mean for 1844,* it may be allowable to conclude, that the 
principal minimum of the horizontal component occurs at the period of full moon ; a secondary, and not very de- 
cided minimum, at the period of new moon ; and maxima, nearly equal, immediately before and after the period 
of new moon, 
* Transactions of the Royal Society of Edinburgh, Vol. XVI., Plate IV. 
