282 
LITTLEHALES. 
Lat. 33° 56' S. CAPE OF GOOD HOPE. Long. 18° 29' E. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
lfins 
o 
— 0.50 
Voyages of the Adventure and Beagle. 
1609.5 .... 
+ 0.20 
Keeling.. 
Do. 
1622.5 .... 
+ 2.00 
1 
1675.5 .... 
+ 8.23 
. 
Walker’s Terrestrial and-Cosmical Magnetism. 
1691.5 .... 
+11.00 
1700 ... 
J-10.25 
1751.5 .... 
+19.25 
| Edm. Halley. 
Tabula Nautica, etc. 
1775.5 .... 
+21.23 
Wales. 
Voyages of the Adventure and Beagle. 
1788.5 .... 
+24.08 
1792.5 .... 
+24.52 
Tabula Nautica, etc. 
1818.5 .... 
+26.52 
1836.5 .... 
+28.50 
Fitz Roy.. 
Becquerel’s Traits du Magnetisme. 
1839.5 .... 
+29.15 
Edm. Halley. 
Tabula Nautica, etc. 
1841.5 .... 
+29.10 
1842.5 .... 
+29.10 
1843.5 .... 
+29.10 
1844.5 .... 
+29.10 
1845.5 .... 
+29.12 , 
Observatory. 
Reports of observations at Cape of Good Hope 
JLO^tD.O .... 
Observatory, on file (1888) in library of United 
1847.5 .... 
+29.21 
States Naval Observatory, Washington, D. C. 
1848.5 .... 
+29.23 
1849.5 .... 
+29.27 
1850.5 .... 
+29.31 
1857.5 .... 
+29.57 
1873.9 .... 
+30.07 
Capts. Nares and Thomson, 
Voyage of H. M. S. Challenger. 
R. N. 
1890.1 .... 
+29.53 
E. D. Preston, assistant, 
Bulletin No. 23, United States Coast and Geodetic 
United States Coast and 
Survey. 
Geodetic Survey. 
Year. 
Observed. 
Computed. 
O-C. 
2 
o-c. 
1605. 
o 
— 0.50 
o 
+ 0.41 
—0.91 
0.8281 
1609.5 .... 
+ 0.20 
+ 0.62 
—0.42 
0.1764 
1622.5 .... 
+ 2.00 
, + 1.50 
+0.50 
0.2500 
1675.5 .... 
+ 8.23 
+ 7.43 
+0.80 
0.6400 
1691.5 .... 
+11.00 
+ 9.74 
+1.26 
1.5876 
1700. 
+10.25 
+11.00 
—0.75 
0.5625 
1751.5 .... 
+19.25 
+19.16 
+0.09 
0.0081 
1775.5 .... 
+21.23 
+22.64 
—1.41 
1.9881 
1788.5 .... 
+24.08 
+24.31 
—0.23 
0.0529 
1792.5 .... 
+24.52 
+24.79 
—0.27 
0.0729 
1818.5 .... 
+26.52 
+27.43 
—0.91 
0.8281 
1836.5 .... 
+28.50 
+28.69 
—0.19 
0.0361 
1839.5 .... 
+29.15 
+28.84 
+0.31 
0.0961 
Probable error of a single observation — ± 22.5'. 
1841.5 .... 
+29.10 
+28.94 
+0.16 
0.0256 
Period = 590 years. 
1842.5 .... 
+29.10 * 
+28.99 
+0.11 
0.0121 
1843.5 .... 
+29.10 
+29.03 
+0.01 
0.0049 
1844.5 .... 
+29.10 
+29.08 
+0.02 
0.0004 
1845.5 .... 
+29.12 
+29.12 
0.00 
0.0000 
1846.5 .... 
+29.14 
+29.18 
—0.04 
0.0016 
1847.5 .... 
+29.21 
+29.20 
+0.01 
0.0001 
1848.5 .... 
+29.23 
+29.24 
—0.01 
0.0001 
1849.5 .... 
+29.27 
+29.27 
0.00 
0.0000 
1850.5 .... 
+29.31 
+29.30 
+0.01 
0.0001 
1857.5 .... 
+29.57 
+29.50 
+0.07 
0.0049 
1873.9 .... 
+30.07 
+29.62 
+0.45 
0.2025 
1890.1 .... 
+29.53 
+29.29 
+0.24 
0.0576 
1 
1 7.4.368 
Empirical equation for determining the declination for any year: v — 14°.63 + 
3.178 sin 0.G1 (t — 1850) + 14.659 cos 0.61 {t — 1850). 
