Dip and Variation of the Magnetic Needle. 109 
Tasre L.—10 Stations. 
'|Annual 
Longi- Tr Variation {Differ- 
Station. Latitude. | tude. | Variation. Date. motion. 1840. ences. 
s- 7 ro age G2 t aq 4 i 
gle of Maine, 48 Own.\67 37-419 igisss+s.s +19 30\— 3 
ae Forks, 45 30 (68 26 14 451825) 8.1) 15 25)+21 
ton 4445 "72 9 10 51/1887 5.7; 11 8i+31 
Farmington, 44 42 170 3 11 201838) 5.2) 11 30|/—55 
mpden, 44 37 |68 46 13 41837) 6.0| 13 — 4 
: 44 30 |70 14] 12 01838} 52) 12 10/+13 
Rumford, 44 30 (70 27) 11 O1838) 52) 1 ine 
Waterville, 44 27 |69 32, 12 81835) 5.7| 12 36/4 6 
Belfast, 44 18 (68 54, 18 O1838 5.7) 13 11/421 
West Thomaston, 143 56 |69 5) 12 01838 5.7, 12 11+ 4 
Adopting for the central position latitude 44° 55’ N., longitude 
69° 31’ W., we obtain ten equations of condition which furnish 
us 6=2°.2317, i. e. +13° 1349, c=+.02555, y = +.02093. 
Computing from these data the variation at the several stations, 
we obtain the differences given in the last column above. Mean 
difference at the six northern stations +0/.5; at the four south- 
ern —1’.0; at the three stations having the greatest computed 
variation +4’.6; three least +3/.0; four intermediate —6’.0. 
_ Tape I.—24 Stations. 
3 
z : 
oe 
8 
Annualy Variation | Differ- 
e 
Lat‘tade. ‘Variation. Dat inotion. 1840. 
a 
“ nce 
| Pes So Tee it ae i c i 
} 45 3b 19385) -f9-! 1835|4, 7 410 18 | +21 
45 é } 7 = * 3 ) 41° j 
aot fs] 3a tee sr| 32/4: 
| 4440 [75 1} 78 152 |—5 
44 28 Ta S21. BY } 8 18 
reas 1-932 [tae 
44 21-473. 49). 8* {7 
Mm F. | 73 33] 83 opt h 
M2273 473 a | 
4355 |7327| 84 ; 427 
43 42 17214] 91 ) 0 
| 4326 173 45) 77 i i 28 
42 52}7229| 8 14 : 4 te 
42 44-173 40) 6 ¢ 47 PS: ot 
42 43 |7313| 74 5.2 +27 
42 39 |73 45| 6 5 46 58 |— 5 
42 32 17234) 7 57 4.9 3 12 |} 445 
22 171 8} 91 5.0 ) 12 10 
#2 4 7246) 8) 5.0 g BES 
42 3 |70 4| 9 20 5.0 145 |45 
41 46 |72 41| 6 5.0 58 |—10 
41 39 |72 26; 61 5.0] 6 35; 14 
41 28 |7121| 7 5.0 45. oe 
