302 
LITTLEHALES. 
Lat. 33° 52' S. 
SYDNEY. 
Long. 151° 12' E. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
1770.. . 
1787.. . 
1793.2 
1803.. . 
1813.. . 
1818.5, 
1823.. .. 
1841.. .. 
1844.. .. 
1848.5 
1851.5 
1858.. .. 
1864.. .. 
1866.5 
1872.. .. 
1875.. .. 
1880.. .. 
— 8.00 
— 8.50 
— 8.77 
— 8.85 
— 8.87 
— 8.78 
— 8.83 
— 9.90 
— 9.42 
— 10.12 
— 9.76 
— 10.00 
— 9.82 
— 9.72 
— 9.57 
9.52 
Cook. 
■ Hunter 
Flinders 
Brewster. 
—8.70, Capt. King, 1817.7 
—8.93, Freyeinet, 1819. 
-8.81, Brewster, 1822. 
-8.80, Rumker and Sir T. 
Brisbane, 1823. 
—8.93, Brewster, 1824. 
’ -9.85, Erebus, 1841. 
—9.95, Sir J. C. Ross, 1841 
H. M S. Fly. 
'—10.08, Rattlesnake, 1848 
—10.15, Rattlesnake, 1849 
'—9.72, Admiral King, 1851 
[—9.80, Admiral 
Capt. Denham. 
> Smalley. 
f —9.62, Russell, 
—9.58, Russell, 
—9.57, Russell, 
—9.53, Russell, 
[—9.55, Russell, 
f — 9.47, H. M. S. 
May, 1874. 
[—9.55, Russell, 
' —9.53, Russell, 
—9.58, Russell, 
—9.60, Russell, 
—9.60, Russell, 
.—9.60, Russell, 
King, 1852. 
1870 . 
1871 . 
1872 . 
1873 . 
1874 . 
Challenger. 
June, 1875.. 
1878 . 
1879 . 
1880 . 
1881. 
1882. 
Voyage of the Adventure and Beagle, 1826-36, 
London, 1839. 
Do. 
Brewster’s Treatise on Magnetism, Edinburgh, 
1834. 
Voyage of the Adventure and Beagle, 1826-’36, 
London, 1839. 
Hydrographic Office archives document. 
Do. 
Voyage of the Adventure and Beagle, 1826-’36, 
London, 1839. 
Hydrographic Office archives document. 
Do. 
Do. 
Phil. Trans. Royal Society, Part II, 1877. 
Hydrographic Office archives document. 
Phil. Trans. Royal Society, Part II, 1877. 
| Do. 
A letter from director of Government observa¬ 
tory at Sydney, dated 1890. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Year. 
Observed. 
Computed. 
O-C. 
o-c 2 . 
o 
o 
1770. 
— 8.00 
—7.82 
—0.18 
0.0324 
1787. 
— 8.50 
—8.35 
—0.15 
0.0225 
1793.2 .... 
— 8.77 
—8.53 
—0.24 
0.0576 
1803. 
— 8.85 
—8.82 
—0.03 
0.0009 
1813. 
— 8.87 
—9.08 
+0.21 
0.0441 
1818.5 .... 
— 8.78 
—9.22 
+0.44 
0.1936 
1823. 
— 8.83 
—9.32 
+0.49 
0.2401 
1841. 
— 9.90 
—9.62 
—0.28 
0.0784 
1844. 
— 9.42 
—9.63 
+0.21 
0.0441 
1848.5 .... 
—10.12 
—9.68 
—0.44 
0.1936 
1851.5 .... 
— 9.76 
—9.70 
—0.06 
0.0036 
1858. 
—10.00 
—9.73 
-0.27 
0.0729 
1864. 
— 9.82 
—9.72 
—0.10 
0.0100 
1866.5 .... 
— 9.72 
—9.72 
0.00 
0.0000 
1872. 
— 9.57 
—9.70 
+0.13 
0.0169 
1875. 
— 9.52 
—9.67 
+0.15 
0.0225 
1880. 
— 9.58 
—9.60 
+0.02 
0.0004 
0.8556 
Probable error of a single observation = ± 10.44'. 
Period = 324 years. 
Empirical equation for determining the declination for any year: v — — 8°.119 
-0.3239 sin 1.112 (t — 1850) — 1.5765 cos 1.112 (t — 1850). 
