330 
LITTLEHALES. 
Lat. 22° 54/ S. RIO DE JANEIRO. Long. 43° 10' W. 
Year. 
Magnetic dip 
or inclina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
1817. 
O 
—14.70 
Becquerel’s Traite du Magnetisme, 1846. 
1890 
—14.72 
Do. 
1821 ... 
—15.43 
Do. 
1826. 
—14.07 
Phil. Trans. Royal Society, 1877. 
1827. 
—14.58 
Lutke.. 
Do. 
1880. 
—13.58 
Erman. 
Do. 
1832. 
—13.62 
Fitz Roy... 
Do. 
1836. 
—12.90 
Beechey. 
Do. 
1837. 
—13.32 
Du Petit Thouars. 
Do. 
r 13.00 
Sulivan. 
Do. 
, 13.02 
.do. 
Do. 
1838.. 
—13.40 ^ r 
j 13.93 
.do. 
Do. 
1.13.62 
.do. 
Do. 
1839. 
—13 12 -f 1^*^ 
Do. 
i 13.16 
.do. 
Do. 
1847. 
—12.28 
“ Rattlesnake ”. 
Do. 
1852. 
—12.62 
“ L’Eugenia ”. 
Swedish Magnetic Survey. 
1857. 
—11.80 
Novara Expedition. 
Phil. Trans. Royal Society, 1877.* 
1866. 
—11.78 
Harkness . 
Do. 
1881. 
—12.13 
Van Rijckevorsel. 
Magnetic Survey of Eastern Part of Brazil. 
1882.7 .... 
—12.00 
Lieutenants Barnaud 
Annales Hydrographiques, 1884. 
and Barnadieres, Fr.N. 
1887.8 .... 
—11.58 
Lieut. Roujon, Fr. N. 
Annales Hydrographiques, 1888. 
1896. 
—12.92 
Lieut. Schvverer, Fr. N.. 
Annales Hydrographiques, 1896. 
Year. 
Observed. 
Computed. 
O-C. 
-2 
O-C . 
o 
o 
1817. 
—14.70 
—15.30 
+0.00 
0.3600 
1820. 
— 14.72 
—14.89 
+ 0.17 
0.0289 
1821. 
—15.43 
—14.87 
—0.56 
0.3136 
1826. 
—14.07 
—14.21 
+0.14 
0.0196 
1827. 
—14.58 
—14.10 
—0.48 
0.2304 
■1830. 
—13.58 
—13.79 
+0.21 
0.0441 
1832. 
—13.62 
—13.59 
—0.03 
0.0009 
1830.. 
—12.90 
—13.24 
+0.34 
0.1156 
1837. 
—13.32 
—13.15 
—0.17 
0.0289 
1838. 
—13.40 
—13.07 
—0.33 
0.1089 
•Probable error of a single observation — ± 14'. 
1839. 
—13.12 
—12.99 
—0.13 1 
0.0169 
1847. 
—12.28 
—12.46 
+0.18 
0.0324 
1852. 
—12.62 
—12.20 
—0.42 
0.1764 
1857. 
—11.80 
—12.01 
+0.21 
0.0441 
1866. 
—11.78 
—11.83 
+0.05 
0.0025 
1881. 
—12.13 
—11.97 
—0.16 
0.0256 
1882.7 .... 
—12.00 
—12.02 
+0.02 
0.0004 
1887.8 .... 
—11.58 
—12.23 
+0.65 
0.4225 
1896. 
—12.92 
—12.68 
' —0.24 
0.0576 
2.0293 
Empirical equation for determining the inclination for any year: I = — 11°.81 
— 0.0009 (t — 1870) — 0.00126 (t — 1870) 2 . 
