XIV INTRODUCTION. 
TABLE 4,—Reading of the Long Scale for the Magnetic Axis of the Declination Magnet. 
First Series. Second Series. Third Series. 
Position of Mean of | Reading Mean of | Reading Mean of 
Magnet. Scale each for Scale each for Scale each 
Reading. | alternate] Magnetic || Reading. | alternate| Magnetic|| Reading. |alternate 
two. Axis. two. Axis. two. 
Inverted 
Direct 255-65 
Inverted : 254-75 
Direct x * 254-00 
Inverted : 255-95 
Direct “ 255-25 
Inverted “ 255-20 
Direct 
Mean reading for magnetic axis, first series, 255°38 
second series, 255°13 
third series, 255-08 
Mean of all the partial results, 255-21. 
Correction for effect of Bifilar and Balance Magnets (Table 5) +0°3 Se. div., 
adopted zero for 1842, 255:5 Se. div. 
12. Corrections to be applied to the observed positions of the Magnet to obtain 
the true declination. 
13. Effect of the Balance and Bifilar Magnets on the Declination Magnet. 
TABLE 5.—Effects of the Bifilar and Balance Magnets on the Declination Magnet. 
N. end of Magnet. 
Bifilar. | Balance. 
f M : 
Declination erreciot Maenc! 
Reading. 
Bifilar. Balance. 
143-30 088 
141-38 
142-57 
144-47 
143-07 
141-28 
0-95 
0-89 
Mean effect of Bifilar magnet on Declination magnet N. pole W.= —0°64 Se. div. 
SpoSSCHO a BASE soph SEMEN. ahcemareaanoscodacoseonebossadbonsa UNgy 0) (2) IDR RABUN HL Sto Gling 
Sum= + 0°30 Se. div. 
After July 30. 1841, the north poles of the Bifilar and Balance Magnets were 
