280 
LITTLEHALES. 
Lat. 18° 56' N. BOMBAY. Long. 72° 54' E. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
179!9 
O 
+5.00 
Mathews 
Encyclopaedia Metropolitana, London, 1848. 
1817. 
—0 00 
Do. 
1845. 
+0.22 
Orlebar.. 
Phil. Trans. Royal Society, Part 1,1875. 
1847. 
—0.23 
Do. 
1849. 
—0.25 
F. A. E. Keller, Fr. Hydr. 
Annales Hydrographiques, 1851. 
Engr. 
1856. 
—0.32 
Schlagintweit. 
Phil. Trans. Royal Society, Part 1,1875. 
1867. 
—0.70 
Do. 
1 
f —0.83, Chambers, 1871. 
1872. 
—0.85 
< —0.86. Chambers. 
1872. 
(Bombay magnetic and meteorological observa- 
7 
o 
0 
CO 
M 
00 
* J 
1 0 
~ 1 
00 
t— 0.88, Chambers, 
1873.. 
( —0.89, Chambers, 
1874. 
] 
1S75. 
—0.90 
i —0.90, Chambers, 
1875. 
V Do. 
[—0.91, Chambers, 1876. 
1 
J 
1878. 
—0.93 
r—0.925, Chambers 
, 1877. 
| Do. 
1—0.933, Chambers, 1878...... 
1881. 
—0.93 
Chamhftrs. 
Do. 
) 
f —0.83, John Dover, 1888. 
1S88.5 .... 
—0.82 
1—0.80, John Dover, 1889. 
i Do. 
Year. 
Observed. 
Computed. 
O-C. 
o-c 2 . 
o 
o 
1722. 
+5.00 
+4.92 
+0.08 
0.0064 
1817. 
+0.00 
+0.63 
—0.63 
0.3969 
* 
1845. 
+0.22 
—0.29 
+0.51 
0.2601 
1847. 
—0.23 
—0.34 
+0.11 
0.0121 
1849. 
—0.25 
—0.39 
+0.14 
0.0196 
1856. 
—0.36 
—0.54 
+0.22 
0.0484 
Probable error of a single observation = ± 12'. 
1867. 
—0.70 
—0.71 
+0.01 
0.0001 
1 Period = 450 years. 
1872. 
—0.85 
CD 
o 
1 
—0.09 
0.0081 
1875. 
—0.90 
—0.78 
—0.12 
0.0144 
1878. 
—0.93 
—0.80 
—0.13 
0.0169 
1881. 
—0.93 
—0.81 
—0.12 
0.0144 
1 
1888.5 .... 
—0.82 
—0.81 
—0.01 
0.0001 
j 
0.7975 
Empirical equation for determining the declination for any year: v = 2°.665 — 
1.625 sin 0.8 (t — 1850) — 3.08 cos 0.8 (t — 1850). 
