154 Terrestrial Magnetism. 
No. 11. Louisville,* Kentucky, Lat. 38° 3! N., Lon. 85° 30’ W. Sept. 7, 1840. 
. Needle No.1. A North. Needle No.2. B North. B North | 
Face of in-| Face of | Face of in-| Faceof | 
strument.| needle. Dip indicated. strument.| needle.. Dip indicated. | 
E. B 68°56’ E. E. TOP L745 
w. w. 71 23 w. w. 70 06.5 
W. ae 68 52  W. E. | 70 145 
E. w. 71 22 E w. 70 10 
B North A North. 
E. a 71 18.5 E. E 70 03.5 
w. w. 68 40 w. w | 69 48.5 
w. E. 71 20 Ww. E. 0 06.5 
ey 68 42 — E. w. 69 47.5 
~8)560 33.5 _ 8)560 34.5 
___ Mean, 70 04.19 Mean, 70 04. 31 | 
No. 12. Mount tase Indiana, Lat. 37° 59! WN., Lon. 87° 47! W. Sept. 10, 1840. 
Need . 1. A North. ~ Needle No.2. A North | 
Face of in-; Face of Faceofing Faceof|. |... 
strument. | needle. Dip indicated. srament| needle. Dip indicated. _ 
E. E. °58 E. gE. | 68°59 
w. 70 05.5 w. 68 36 
w. E 67 56.5 Ww E. 68 56 
E. Ww. 70 09 ae 68 38 
B North. =. ~-B North. 
E. E 70 04 gE. oF £ 69 04.5 
w. Ww | 67 38.5 Ww Ww 69 03 
w. E 70 04 w. E 69 13.5 
E. "= 6f.36 E. w. 69 Oe 
8)551 30.5 : ~ 8)551 Te, mee 
Mean, 68 56.31 Mean, 68 66.25 _ 
* The abo 
bove observations were ¢ made on Corn Island, in the Ohio. At Jacob's 
Woods, two miles south of the island, the dip was 69° BY. 1. 
On August 31, 1839, the 3 on — Tend — <r 
Sept. 7, 1840, fy a 
March 11, pe, the vp at pa s Wood tom . a 
7, 18 
S) 
69° 57! 
The above exhibits fe, greatest change of us oA 4 I neve. ever noticed in # 
short a distance as two miles 
