io Captain Sabine’s experiments to determine the 
And 
AD _j_ BC o, 76915x0,4599 , 0,68034x0,43907 
B + D •” B + D 0,89897 "1 0,89897 °> 3934 ° 
+ 0,33229 = ©>72577 = twice the cotangent of the dip ; 
therefore, 0,7 IP 7 — 0,36288 ; cot. of 70° 03', 3 north dip. 
Experiment 2. August 6th , 1821, with sphere No. 1, screwed 
up close to the needle ; in this experiment the alternate arcs 
were on the south side of the vertical, and were therefore 
read and used negatively. 
Face A towards the observer. Face B towards the observer. 
1 
° ' 
1 N. end 49 20 S. end 
O / 
49 00 N. end 
O / 
22 I4 
O / 
S. end —22 06 
F ace of the Circle East ^ 
49 20 
49 00 
— 22 14 
— 22 06 
1 
L 49 22 
49 02 
— 22 17 
— 22 12 
49 22 
49 °4 
—22 40 
22 20 
Face WestJ 
49 22 
49 °3 
— 22 40 
22 20 
1 
l 49 22 
49 04 
—22 38 
22 l8 
49 Zl >3 
49 02,1 
— 22 27, 
I 22 17 
49 11,7 = F 
- 22 22 — f . 
Poles inverted. 
0 , 
O t 
0 / 
O / 
| 
47 15 
47 °° 
— 20 20 
20 IO 
Face WestJ 
47 20 
47 00 
—20 20 
20 08 
I 
L 47 H 
46 56 
— 20 20 
20 04 
I 
47 00 
46 40 
— 20 10 
20 OO 
Face East-^ 
47 °° 
46 40 
— 20 10 
—'9 5 8 
L 47 00 
46 40 
-—20 10 
—19 58 
47 o8 A 
46 49,3 
1 
N 
O 
HI 
v-n 
20 03 
46 58,7 — G 
-20 09 ~g 
Here tan F=: tan 49 11,7 = 1,15831; and tan G = tan 46 58,7 = 1,07156 
tan/= tan-— 22 22 = — 0,41149 
tan F + tan/” = A = 0,74682 
tan F — tan f — B 1,5698 
tan g — tan -—20 09 = — 0,36694 
tan G + tang — C — 0,70462 
tan G — tang=D = 1,4385 
B + D = 3,0083 
AB , BC 0,74682 x i, 43 g g 1 o,7 046 2 X 1,5698 _ 7 
B 4. D ' B + D 3,0083 ' 3,0083 >00/ 
-j- 0,36769 = 0,724,8 ; = 0,3624 cot. of 70 04,7 N. dip. 
2 
