Month. | 
254 ABSTRACTS OF THE MAKERSTOUN OBSERVATIONS, 1843. 
VARIATIONS OF THE TOTAL MAGNETIC FORCE WITH REFERENCE TO THE Moon’s DECLINATION. 
Means of Groups. 
27 days to I as Moon farthest North, 0°000101 | 13 days to 15 bet Moon farthest South, 0:000072 
Dy Aacwe 0000084 | 16 ...... 19 0:000022 
Gane ac 3 ase 0:000058 | 20 ...... 22... 0:000017 
Dewees PA see 0:000041 | 23 ...... YAiSe pat 0:000031 
There seem, therefore, to be mawima of the total magnetic force when the moon has its greatest north and 
south declinations, and minima about the time when the moon is on the equator. The principal maximum occurs 
when the moon has its greatest north declination, and the principal minimum when it is on the equator moving 
northwards ; the secondary maximum and minimum are not shewn so distinctly. 
VARIATIONS OF THE TOTAL MAGNETIC FORCE WITH REFERENCE TO THE MOON’s DISTANCE FROM 
THE EARTH. 
Means of Groups. 
6 days after Apogee to 6 days before Perigee, 0000103 | 6 days after Perigee to 6 days after Apogee, 0:000041 
5 days to 2 days before Perigee, ............ 0:000081 | 5 days to 2 days before Apogee, ............ 0:000037 
1 day before to 1 day after Perigee,......... 0:000064 | 1 day before to 1 day after Apogee, ...... 0:000024 
2 days to 5 days after Perigee, ............ 0-000082 | 2 days to 5 days after Apogee, ............ 0:000069 
EXTREME POSITIONS. 
TABLE XXVIII.—Differences of the Extreme Readings of the Three Magnetometers from the 
Monthly Means for the Hours at which they occurred, for each Month in 1843, as deduced from 
the Nine Daily Observations, together with the Ranges of the Three Magnetic Elements in each 
Month. 
Westerly Declination. Bifilar Magnetometer. Balance Magnetometer. Ranges. 
Greater than Less than Reading greater} Reading less || Reading greater Reading less Decli- | Horizontal 
Mean. Mean. than Mean. than Mean. than Mean. than Mean. nation. jcomponent 
| a. Se. Dive | & he| Se Dive a. | ull Dic. Div. {la he | Mie, Div. | 
+ 4-15 | 22 : y]+ 9-4 | 28 8|—12-9 i)+ 85-0 — 44-5 || 12-70 | 0:00239 
+15-95 + 10-0! 14 10|)—14-5||24 8/+123-9 — 47-8)||59-29 | -00267 
+ 10-94 +19:-4) 7 8|—24-8 8 |+ 292-7 |: — 52-2) 33-02 | -00474 
+ 10-79 +43:9 — 68-8 3 |+ 344-0 20|— 105-4 | 33-38 | -01265 
+ 4-22 +184 —79-1 + 79:8 — 257-2 || 29.84 | -01069 
+ 7:96 +13:3 22 |— 10-6 3/4+ 53-7 — 38-6|| 25-60 | -00474 
+ 3:55 +96-2 22 | — 42-0 4|}+ 246-1 — 56-7||40-48 | -01627 
+ 4-23 + 22-6 — 36-8 +116-1 — 153-0 || 19-86 | -00744 
+ 13-00 +17-4 —16-4 I{+ 51-5 — 46-2) 24-90 | -00508 
+ 6-16 +38-1| 4 22)-— 9-0 5/+ 90-8 63-8 || 31-39 | -00617 
+ 5-89 +10-8|] 3 — 10-3 + 32-6] 2 20-3 | 14-20 | -00335 
+ 5-45 . +15-1 — 18-6 3/+ 94-5 46-2 || 21-82 | -00412 
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