OBSERVATIONS ON THE MAGNETIC DIP AND DECLINATION. 343 
X. OBSERVATIONS FOR THE DIP OF THE MAGNETIC NEEDLE. 
Date and place of observation.—1840, October 18th.—At astronomical station, four thou- 
sand five hundred and seventy-eight feet due north from the monument at the source 
of the river St. Croix; on the boundary between Maine and New Brunswick. Lati- 
tude 45° 57’ 23’.6, N.; Longitude 67° 46’ 45”, west of Greenwich. 
ae Aen. eae. WBked [Mean solartime North end of Needle|South end of Needle Mean of both ends| Attached a heias 
Needle.|markedend|{nstrument.| side | febservation.| __reads. ——|_sreads. oF Needles (Thermometer. of 
of needle. of Needle,}| HH, M. eg) Ming Lenthy, Deg.|Mins.§'Tenths,| Deg. |M ins.§Tenths,| (Fahrenheit.) Observer. 
BOT N E E 1.30 p.m.76 . 37 76. 15 76 . 26 | J.D.G. 
«“ “ Ww WwW 1.45 |77. 05 77.28 77 . 16.5 
be 2 Ww E 1.50 76.16 76. 35 76 . 26 
. : E W | ise) Ae a7. UY 75186 | 
Weather clear and dry. 
ayes Oe ee (2.40P.m/77.10 ~~ (76. 52 (77. 01 | 6a" ae. 
ry a W W 2.48 76. 57 TR OF 4% 02 | 
“ “ WwW E 3.00 76. 55 77.15 7. 05 
«“ “ E W | 3,10 97,68 76, 52 77 . 00 
Needle No. 8, with marked end north, gives, Cou 76° 61'.6 
Decdle..No. 3) with marked ¢nd. south, gives, i000 eae A ces O08 
Dip by sixteen observations on needle No.3, . . . 2... ey 76° 86'.°75 
1840-—October 20th.—At the same station, observed on needle No. 4 as follows, viz.: 
4 N E BE | 11.05.a.m.|75 . 45 75.15 75. 30 | 60°. DG] 
& & Ww Ww 11.20 77. 50 78.10 78. 00 | 
“ &“ W iE 11.25 75.20 75.20 75. 20 
| eee E W | 11.30 78.05 77. 50 77.. 57.8 
4 fae lee i E 0.15 P.m./78 . 38 78.15 78. 26.5 | 61% J.D.G| 
“ és Ww Ww 0.25 75. 80 75. 45 75. 87.5 | 
‘“ “ Ww 10) 0.30 78 . 08 78 29 78.15 
és & E Ww 0.88 76. 40 16. TU 76. 25 
It was raining the whole time occupied in observing on needle No. 4, to-day, and the 
atmosphere was very moist, but the needle and its axis, and also the agate supports at the 
centre of the dip circle, were kept as dry as possible by frequently wiping them with soft 
chamois leather. 
Needle No. 4 gives, with.marked end north, .:scie.ornpc ed. O38) ee xe 7649.87 
i ee ee ee ee U 
Dip by sixteen-observetions on needle.No.4,..., . 4 wr. «i+. % . 76° 56.43 
Notr.—Needles No. 3 and No. 4, made by J. N. Baur, of New York, were furnished by him unmagnetized. 
They were magnetized on the 18th of October, and the above are the first observations ever made with them. 
Date and place of observation. —1840—October 20th.—At the same station as before. 
1 Ss E LD 2.15 p.m./78 . 30 78.19 [7.268 | oF 15.D.G, 
« “ Ww WwW | 2.55 (75. 40 75 . 55 75. 47.5 63 
ee “ WwW E 3.27 76,07 76. 25 76.10 60 
$ es E W 3.55 70.27 78.10 78. 18.0 61 
At 2h. 55m., cloudy: 3h. 27m., raining: 3h, 55m., sky clear, flying clouds. 
VOL. 1x.—90 
