equally near the bottom, still the
same effects and the _same direction_ of electrical current was obtained.
But in those extreme proportions the effects did not appear so strong as
when the surface of the mercury was about the middle, or between that and
an inch from each end. The magnet was eight inches and a half long, and
three quarters of an inch in diameter.

222. Upon inversion of the magnet, and causing rotation in the same
direction, i.e. always screw or always unscrew, then a contrary current of
electricity was produced. But when the motion of the magnet was continued
in a direction constant in relation to its _own axis_, then electricity of
the same kind was collected at both poles, and the opposite electricity at
the equator, or in its neighbourhood, or in the parts corresponding to it.
If the magnet be held parallel to the axis of the earth, with its unmarked
pole directed to the pole star, and then rotated so that the parts at its
southern side pass from west to east in conformity to the motion of the
earth; then positive electricity may be collected at the extremities of the
magnet, and negative electricity at or about the middle of its mass.

223. When the galvanometer was very sensible, the mere spinning of the
magnet in the air, whilst one of the galvanometer wires touched the
extremity, and the other the equatorial parts, was sufficient to evolve a
current of electricity and deflect the needle.

224. Experiments were then made with a similar magnet, for the purpose of
ascertaining whether any return of the electric current could occur at the
central or axial parts, they having the same angular velocity of rotation
as the other parts (259.) the belief being that it could not.

225. A cylinder magnet, seven inches in length, and three quarters of an
inch in diameter, had a hole pierced in the direction of its axis from one
extremity, a quarter of an inch in diameter, and three inches deep. A
copper cylinder, surrounded by paper and amalgamated at both extremities,
was introduced so as to be in metallic contact at the bottom of the hole,
by a little mercury, with the middle of the magnet; insulated at the sides
by the paper; and projecting about a quarter of an inch above the end of
the steel. A quill was put over the copper rod, which reached to the paper,
and formed a cup to receive mercury for the completion of the circuit. A
high paper edge was also raised round that end of the magnet and mercury