C. A. Schott on Magnetic Declination. 341 
Year. (Charleston, 8. c.| Savannah, Ga. Mobile, Ala. 
1770 a3 4 * ‘ 
1780 ai - . . 
1790 —4:1 | ee" 
1800 41 | —4'1 —T1 
1810 ~4:0 42 —7T2 ‘ 
1820 —3'6 | —42 —73 
1830 wo  SEAl ett —72 
1840 —28 | —40 —71 
1850 —22 — BY To 
1860 <1] —35 “—68 
The following formule for stations of the western coast, be- 
tween San Diego and Cape Disappointment, forming group 3, 
have been copied from p. 234 of the report for 1856. 
Me Wied ye oy flceee 
No. Locality. Lat. [Long.§ 
‘ . ° 
San Diego, $42 | 11713 |D=—1217—0019n+0:00018n2} 
Monterey, 3638 | 12154 |D=—14:19—0°050n+0-00047n* 
San Francisco. 3748 | 12227 |D=—15:14—0:028n+0-00025n* 
Cape Mendocino, 40 26 124 22 |D=—16'29—0°029n 
| 5 |Cape Disappointment,, 4617 | 12402 |D=—19°65—0019n 
eclination) may be taken the same for all stations, viz., in 
—1 
1840, —1"6, in 1850, —1"2, in 1860, —0"8. 
a Disap-| 
— por Monterey. paint. ponacsiad: Hlotenat 
°o o °o 
vio | <irt | =17eR eee) PSIeE | <ie9 
1800 11 2-3 141 54 19°1 
1810 11-7 3-0 14°5 19°3 
1820 12:0 3°6 14°8 16-0 19°5 
1830 12-2 4-2 151 163 19°7 
1840 | 128 4°6 154 6" 198 
1850 12°5 50 15°6 169 2 
1860 | ~—12- —15'3 —15'8 179 —20°2 
The next station teed south of California, is San Blas, 
Mexico, lat, 21° 39’ N., long. 105° 16’ W. of Gr., which gave 
the following expression (see p. 234, C. S. report for 1856), 
D——8°63 —0-042n—0°00031n?, S 
Which equation, when compared with those above, shows. re- 
versal j i ‘ent of n? or an opposite curva- 
in the sign of the ee ¥ a Blan in 1850 accord 
