horizontal needle when under the influence of magnets. 373 
So that the three points of instable equilibrium were nearly 
S 55° 35 ' W, S 59° 20' E, N 20° 30' E. 
At the three points N 56 0 40' W, S i5°55 / W, N 4Q°55 / E, the 
north end of the needle, after being agitated, settled steadily. 
Hence the six points of equilibrium, in their order round the 
compass, were. 
Stable. Instable. Stable. Instable. Stable. Instable. 
N 56°4o' W, S 55° 35' W, S^ss'W, S 59*20' E, N 4 o 0 55'E, N2o°3o'E. 
Vibrating the needle from S 6o° W, it made six vibrations 
in thirty seconds about the point N 56° 40' W ; vibrating it 
from S 54 0 W it made four vibrations in twenty seconds 
about the point S 15 0 55' W : I could not obtain the vibrations 
about the point N 40° 55 ' E, on account of its proximity to the 
instable point N 20°3o'E. 
I have been thus particular in describing the steps which 
I took previous to the first set of observations, in order that 
the nature and situation of the three points of stable equili- 
brium may be clearly understood, and to render unnecessary 
any previous explanation for the other sets of observations. 
