horizontal needle when under the influence of magnets. 377 
In this position of the magnets, their forces so very nearly 
balance the terrestrial forces, that the southerly and easterly 
points of equilibrium are soon lost in the westerly , the charac- 
ter of which is in consequence, as we might expect, somewhat 
ambiguous. The easterly point, when it could be observed 
in the morning, approached the north from between seven and 
eight o’clock until it was lost in the westerly point ; and, from 
its first appearance in the afternoon, it receded from the north 
till the evening, except on the tenth, when it again approached 
the north previous to its finally receding. With respect to 
the deviation of the southerly point, its direction appeared to 
be plus till about eight o’clock in the morning, after which it 
was minus as long as it could be observed ; and when again 
observed it had become plus : which, as far as the observa- 
tions go, agrees with those at the south, before mentioned. 
After making the observations at 8 h P. M. on the 14th of 
May, pins being fixed by the sides of the magnets so that I 
could make them recede from the needle in the same line, 
I drew them back by very small distances, to see whether, 
from this point, an increase of the terrestrial force would 
give changes in the points of equilibrium of the same nature 
as those which had taken place in the preceding observations : 
I found them to be as under. 
14th May, 8 h 15 m P. M. 
Distances. 
Points of Equilibrium. 
11.725 
11.742 
1 1.760 
1 1 *775 
0 / 
N. 22 25 W. 
21 OO 
l 9 35 
18 30 
0 / 
N. 15 50 E. 
10 30 
/ 7 4 ° X 
\ not stable J 
no point 
S. 4 5 5 W. 
6 40 
6 55 
8 00 
3C 
MDCCCXXIII. 
