292 
LITTLEHALES, 
Lat. 34° 54' S. MONTEVIDEO. Long. 56° 12' W. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
1789.7 .... 
o 
—13.67 
Brewster’s Treatise on Magnetism, Edinburg, 
1834. 
1807 
—13.33 
.Becquerel’s Trait 6 du Magnetisme. 
1890 
12 78 
Do. 
1826* .... 
—10.39 
Voyages of the Adventure and Beagle, London, 
1839. 
189,7 
19 19 
Phil. Trans. Royal Society, Part II, 1877. 
1890 
—11 72 
Do. 
1880 
—11.70 
Do. 
• 
f Fitz Rov, 1833. — 12°.66 . 
1 n 
1834.5 .... 
—11.62 
> Do. 
] La Bonite, 1836, — 
-109.59.,... 
1 
1843.5 .... 
—10.70 
l-Sullivan . 
Do. 
1844.6 .... 
— 10.88 
j 
1852 ... 
— 10.22 
Do. 
1866 
— 9.35 
Smithsonian Contributions to Knowledge, No. 
239, 1873. 
1882.6 .... 
— 8.23 
Lieuts. Barnaud and Bar- 
Annales Hydrographiques, 1884. 
nardibres. 
1883* . 
— 7.90 
Lieut. H. W. Lyon, U. S. N.. 
Naval Professional Papers, No. 19. 
1888.4 .... 
— 7.32 
Lieut. Davenport, U. S. N.... 
Hydrographic Office Publication, No. 109. 
f Lieut. Bloeklinger, U.S.N., 
Do. 
Jan.. 1893. —8.27. 
1893.2 .... 
— 7.62 
1 Lieut. Mottez, Fr. N., May, 
Annales Hydrographiques, 2d vol., 1893. 
1 1893, —6.97. 
1894.3 .... 
— 7.67 
Lieut. J. H. Bull, U. S. N.... 
Hydrographic Office archives document. 
Year. 
Observed. 
Computed. 
O-C. 
s— m 
o-c. 
1789.7 .... 
o 
—13.67 
o 
—14.11 
0.44 
0.1936 
1807. 
—13.33 
—13.02 
—0.31 
0.0961 
1820. 
—12.78 
—12.33 
—0.45 
0.2025 
1827. 
— 12.12 
—11.91 
— 0.21 
0.0441 
1829. 
—11.72 
—11.78 
+0.06 
0.0038 
1830. 
—11.70 
—11.72 
+ 0.02 
0.0004 
1834.5 .... 
—11.62 
—11.44 
—0.18 
0.0324 
Probable error of a single observation = ± 11.76'. 
1843.5 .... 
—10.70 
—10.84 
+0.14 
0.0196 
Period = 360 years. 
1844.6 .... 
— 10.88 
—10.76 
— 0.12 
0.0144 
1852. 
— 10.22 
—10.27 
+0.05 
0.0025 
1866. 
— 9.35 
— 9.32 
—0.03 
0.0009 
1882.6 .... 
— 8.23 
— 8.28 
+0.05 
0.0025 
1888.4.... 
— 7.32 
— 7.95 
+0.63 
0.3969 
1893.2.... 
— 7.62 
— 7.70 
+0.08 
0.0064 
1894.3. 
— 7.67 
— 7.64 
—0.03 
0.0009 
1.0168 
* Omitted in investigation. 
Empirical equation for determining the declination for any year: v — — 10°.28 
+ 3.9 sin (t— 1850) — 0.119 cos (i —1850). 
