9 
the intensity of magnetic forces ^ &c. 
two joined together was 23.84 inches ; so that the length of 
each might be taken to be very accurately 1 1.92 inches : they 
are .95 inch wide, and .375 inch thick. In all my observations 
the same magnet was always placed on the same side of the 
centre of the needle ; so that in ascertaining the situations 
of their poles I distinguish one as the north, the other as 
the south magnet. The distances of the poles of the magnets 
from their ends, determined in the same manner as for the 
needle, were measured on each side, and a mean of the whole 
taken to obtain the distances between the poles ; they were 
these : 
Mean 
North Magnet. 
South Magnet. 
North Pole. 
South Pole. 
North Pole. 
South Pole. 
0. 82 inch. 
0. 81 
0.86 inch. 
0.86 
0.84 inch. 
0.84 
0. 77 inch. 
0. 76 
0.815 
0.86 
0.84 
0.765 
Taking half the sum of these, 1.64 inches, from the length of 
each magnet, we have 10.28 inches for the distance between 
the poles. 
A meridian line being drawn on a firm table, standing on 
a stone floor, the compass was accurately adjusted on it, so 
that the needle pointed to zero on the graduated circle. The 
magnets were fixed at the bottoms of earthen pans, secured 
in such a way to rectangular pieces of board that their 
positions could not be accidentally changed, and projecting 
from these boards were small pieces of brass, on each of 
which a line was drawn to indicate the position of the axis of 
the magnet ; the horizontal distance of the edge of each of the 
C 
MDCCCXXV. 
