In the middle of the concave side, there is a groove
twelve inches deep, in which the extremities of the axle are
lodged, and turned round as there is occasion.
The stone cannot be removed from its place by any force, because
the hoop and its feet are one continued piece with that body of
adamant which constitutes the bottom of the island.
By means of this loadstone, the island is made to rise and fall,
and move from one place to another. For, with respect to that part
of the earth over which the monarch presides, the stone is endued
at one of its sides with an attractive power, and at the other with
a repulsive. Upon placing the magnet erect, with its attracting
end towards the earth, the island descends; but when the repelling
extremity points downwards, the island mounts directly upwards.
When the position of the stone is oblique, the motion of the island
is so too: for in this magnet, the forces always act in lines
parallel to its direction.
By this oblique motion, the island is conveyed to different parts
of the monarch's dominions.
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