298 
LITTLEHALES. 
Lat. 22® 54' S. RIO DE JANEIRO. Long. 43° 10 7 W. 
Year. 
Magnetic 
declina¬ 
tion. 
Authority. 
Observer. 
Where recorded. 
1768. 
O 
—7.57 
Cook. 
Voyage of the Adventure and Beagle, London 
1839. 
1783.5 .... 
—6.60 
Anuario Hidrografico de Chile, Ano XII. 
1787. 
—6.20 
Hunter. 
Voyage of the Adventure and Beagle, London 
1839. 
! 
! —3.57, Freycinct, 1820. 
I 
1820.5 .. 
—3.66 
i 
—3.70, Rumkert and Bel- j 
^Becquerel’s Traite du Magnetisme. 
i 
linghausen, 1821. 
J 
i 
' —3.00, Owen, 1822. 
1 
1824.5 .... 
2.93 
\ 
—3.12, Beechey, 1825. 
\ Do. 
1 
k —2.62, King, 1826. 
1 
1 QQQ 
O A/1 
'J 
f —2.13, Ermann, 1830. 
Reise um die Erde, etc., Berlin, 1835. 
loOO.,. 
-Z.U4: 
1 
[—2.00, Fitz Roy, 1836 .1 
Voyage of the Adventure and Beagle, London, 
1839. 
1851.9 .... 
—1.25 
Annalen der Hydrographie, 1877. 
1857. 
+1.33 
Storm ley and Richards.! 
British Admiralty Chart, No. 541. 
1866. 
+2.70 
Hark ness.| 
Smithsonian Contributions to Knowledge, No. 
239, 1873. 
1876.5 .... 
+4.43 
Lieut. S. W. Very, U. S. N.J 
Appendix No. 7 to Coast and Geodetic Survey 
1 
Report for 1888. 
1882.6 .... 
+4.65 
Lieuts. Barnardieres and 1 
French Magnetic Survey. Annales Hvdrograph- 
Barnaud, Fr. N. 
iques, 1884. 
1885. 
+5.33 
Cruls. 
Anuario Hidrografico de Chile, Ano XII. 
1887.7 .... 
+5.95 
Lieut, de Roujon, Fr. N.1 
Annales de Hydrographiques, 1888. 
Year. 
Observed. 
Computed. 
O-C. 
o-c 2 . 
o 
o 
1768. 
—7.57 
—7.01 
—0.56 
0.3136 
1 
1783.5 .... 
—6.60 
—6.85 
+0.25 
0.0625 
1787. 
—6.20 
—6.73 
+0.53 
0.2809 
1820.5 .... 
—3.66 
—4.03 
+0.37 
0.1369 
1824.5 .... 
—2.93 
—3.56 
+0.63 
0.3969 
1833. 
—2.04 
—2.46 
+0.42 
0.1764 
Probable error of a single observation = ± 26'. 
1851.9 .... 
—1.25 
+0.28 
—1.53 
2.3409 
Period = 360 years. 
1857. 
+1.33 
+1.06 
+0.27 
0.0729 
1866. 
+2.70 
+4.43 
+2.45 
+4.04 
+0.25 
+0.39 
0.0625 
1876.5 .... 
0.1521 
1882.6 .... 
+4.65 
+4.94 
—0.29 
0.0481 
1885. 
+5.33 
+5.29 
+0.04 
0.0016 
1887.7 .... 
+5.95 
+5.67 
+0.28 
0.0784 
J 
1 
4.1597 
Empirical equation for determining the declination for any year : v = 1°.814 + 
8.655 sin (t — 1850) — 1.825 cos (t — 1850). 
