XXXVI GENERAL RESULTS OF THE MAKERSTOUN OBSERVATIONS. 
diately before and after those stated, a secondary minimum occurring at conjunction, and a secondary maximum 
at opposition ; but these secondary points are probably accidental. 
2d, The departure of the horizontal component from its monthly mean position for the corresponding hour 
is least when the moon is farthest south and also when farthest north; maxima occurring at the intermediate 
periods (see No. 16), 
DIURNAL VARIATIONS FOR THE HORIZONTAL COMPONENT OF MAGNETIC FORCE. 
Diurnal Variation of the Horizontal Component.—The discussions for 1843 and 1844 will be found in 
the volumes for these years, the Tables for 1845 and 1846 are given in this volume, pages 13 and 34. Table 
31 has been formed from all the ordinary daily observations made in the 4 years, in the manner already de- 
scribed for the declination (Nos. 26, 27.) 
TABLE 31.—Diurnal Variations of the Horizontal Component of Magnetic Force for each Month, as 
deduced from the Regular Daily Observations made during the Four Years 1843 to 1846. 
March, 
KCOODNAOURwWNWK Ow 
—_ 
69. The following are the approximate epochs of maxima and minima in apparent time, as deduced from the 
numbers in Table 31; the principal maximum is distinguished by +, the principal minimum by —, 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 
h., m. h. m. h, m. hom hm h m h. m h. m. h. m. h. m. h, m. h. m. 
Min. 2210 -2215 -2215 -2215 22 0 2150 2140 21 25 —2150 -2210 -—2240 -—22 40 
Max. +4 0 +245 4415 + 5 46 5 15 6 45 650 510 +420 +5 +6 0 4615 
Min. -40 -l4 0 140 VA OR iresciceel  rerens eee Mn ita 2 14 0 13 0 ll 0 —12 0 
Max. +18 0 18 45 18 0 L7x Bia access disenc=sWeliesramssy |) (sas > 17 15 16 0 +1830 +418 0 
The diurnal variation of the horizontal component, at Makerstoun, consists of one maximum and one 
minimum in the four months May till August, and of two maxima and two minima in the eight months 
September till April; in each of the four months November till February, the two maxima have nearly equal 
values, and in each of the last three of these, the two minima are also nearly equal; from March till April, 
