286 
LITTLEHALES. 
Lat. 38° 32' N. FAYAL, AZORES. Long. 28° 33' W. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
1589.7 .... 
o 
—3.09 
Wright. 
Hansteen’s Magnetismus der Erde, Christiana, 
1819. 
1775.5 .... 
22.12 
Cook.. 
Do. 
1814. 
23.50 
Reid. 
Becquerel’s Traits du Magnetisme. 
1829.. 
25.92 
Liitke. 
Phil. Trans. Royal Society, Part I, 1875. 
Do. 
1842. 
27.00 
25.87 
Vidal. 
1890. 
Lieut. J. C. Colwell, U. S. N.. 
Hydrographic Office Publication, No. 109. 
1891. 
24.50 
H. M. S. Acorn .... 
Letter from the British hydrographer, dated May 
11, 1893. 
Year. 
Observed. 
Computed. 
O-C. 
_2 
O-C . 
1589.7 .... 
1775.5 .... 
1814. 
1829. 
1842. 
o 
—3.09 
22.12 
23.50 
25.92 
27.00 
25.87 
24.50 
o 
—2.92 
21.03 
25.17 
26.04 
26.49 
25.06 
24.97 
—0.17 
+1.09 
—1.67 
—0.12 
+0.51 
+0.81 
—0.47 
0.0289 
1.1881 
2.7889 
0.0144 
0.2601 
0.6561 
0.2209 
1 
i Probable error of a single observation = ± 46'. 
' Period = 530 years. 
1890. 
1891. 
5.1574 
Empirical equation to determine the declination for any year: a = 11°.82-f- 
0.23 sin || {t — 1850) + 14.75 cos B (t — 1850). 
