Select two stones from three to six inches long, and about half as
thick; lay one flat on the ground, on which place one end of the other,
raising the reverse end to an angle of forty-five degrees, and just
over the centre of the stone (with which it must form a T,) supporting
it in that position by a piece of thin twig or stick, one, or one and
a half inch long; if the raised stone be now smartly struck about the
centre, with the little finger side of the fist, the stick will give
way, and the stone will be broken to pieces: the stones must be laid so
as not to slip, otherwise the experiment will fail.