Spin a top, and it will for some time stand “asleep,” as it is called
in the parlance of the play-ground. The cause is thus explained by
Dr. Arnot, in his valuable _Elements of Physics_: “While the top is
perfectly upright, its point being directly under its centre, supports
it steadily, and although turning so rapidly, has no tendency to move
from the place; but, if the top incline at all, the _side_ of the peg,
instead of the very _point_, comes in contact with the floor, and the
peg then becomes a little wheel or roller, advancing quickly, and,
with its touching edge, describing a curve somewhat as a skater does,
until it becomes directly under the body of the top, as before. It thus
appears that the very fact of the top inclining causes the point to
shift its place, so that it cannot rest until it come again directly
under the centre of the top.”