Ixx GENERAL RESULTS OF THE MAKERSTOUN OBSERVATIONS. 
TABLE 66.—Variations of the Total Magnetic Force with reference to the Moon’s Hour-Angle for 
the Winter and Summer Lunations, and for all the Lunations of the Years 1844 and 1845. 
Winter Lunations. Summer Lunations. All the Lunations. 
1844. : Mean. 1845. Mean. 1844. 1845, 
0-000 4 0-000 0-000 0-000 0-000 0-000 
— 055 +011 +015 —019 +006 
-—O091 +030 +012 — 048 +028 
— 068 5 +020 +005 — 040 —015 
— 068 5 +001 —011 — 045 —015 
— 052 — 036 —035 — 043 — 037 
—010 | +002 — 004 —010 +001 
+066 | +020 +006 +029 | +025 
+106 | +027 +024 +065 +035 
+084 55 —003 +017 +062 +023 
+054 B — 028 —009 +031 000 
+045 5 —039 — 022 +019 | —026 
— 006 — 006 000 +001 
146. Variation of the Total Magnetic Force with Reference to the Moon’s Hour-Angle.—Of the four indepen- 
dent results in Table 66, that for the winter lunations of 1844 has the greatest range, and only one maximum 
and minimum, the maximum occurring about 2 hours after the moon’s inferior transit, and the minimum about 
2k hours after the superior transit : the three other results shew two maxima and two minima as follow ;— 
A maximum from 2 to 4 hours after the moon’s inferior transit. 
A minimum from 4 to 24 hours before the moon’s superior transit. 
A maximum from 0 to 24 hours after the moon’s superior transit. 
A minimum from 6 to 8 hours after the moon’s superior transit. 
In the mean of all, as shewn in the last column of Table 66, the first minimum and second maximum noted above, 
are scarcely visible, owing to the effect of the great range of the exceptional result for the winter lunations of 
1844. The epochs from the means of all are— 
The maximum of total force 23 hours after the moon’s inferior transit. 
ASTIN Sy feo onscaisiisss 2 hours before ............ superior transit. 
ACMA RAMU Sees oes ses CAT) RMIT T ols acces superior transit. 
The minimum ............... 8 hours after ............ superior transit. 
It is probable that the mean of all the lunations is vitiated by the winter lunations of 1844, and that the 
epochs given above for the remaining lunations of the two years are near the truth. 
ComBinED Motions or THE MAGNETIC NEEDLE. 
147. Motions of the North End of a Magnetic Needle supposed freely suspended in the direction of the Magnetic 
Force.—These motions have been represented in Plates VI—VIII. by projecting the variations of dip, given in 
the previous Tables, as ordinates to the abscissee deduced from the variations of declination for the same epochs 
multiplied by the cosine of the dip (=0-32). As great care has been bestowed on the determination and veri- 
fication of the coefficients of reduction for the bifilar and balance magnetometers, upon which the element of 
dip depends, it is conceived that considerable confidence may be placed in the accuracy of these figures as re- 
presentatives of the motions of the north end of a needle supposed freely suspended in the direction of dip at 
Makerstoun. No attempt has been made in these discussions to introduce theoretical views, but a consideration 
of the figures in the Plates will probably show the futility of many of the theories brought forth to explain the 
motion in declination. d 
148, Annual Motions—The annual motion deduced from the observations of the three magnetometers for the 
four years 1843-6 is shown in figure A, Plate VI. In order to exhibit a more symmetrical form of the annual 
