22. Another mode of accumulating power arises from lifting a
weight and then allowing it to fall. A man, even with a heavy
hammer, might strike repeated blows upon the head of a pile
without producing any effect. But if he raises a much heavier
hammer to a much greater height, its fall, though far less
frequently repeated, will produce the desired effect.

When a small blow is given to a large mass of matter, as to a
pile, the imperfect elasticity of the material causes a small
loss of momentum in the transmission of the motion from each
particle to the succeeding one; and, therefore, it may happen
that the whole force communicated shall be destroyed before it
reaches the opposite extremity.

23. The power accumulated within a small space by gunpowder
is well known; and, though not strictly an illustration of the
subject discussed in this chapter, some of its effects, under
peculiar circumstances, are so singular, that an attempt to
explain them may perhaps be excused. If a gun is loaded with ball
it will not kick so much as when loaded with small shot; and
amongst different kinds of shot, that which is the smallest,
causes the greatest recoil against the shoulder. A gun loaded
with a quantity of sand, equal in weight to a charge of
snipe-shot, kicks still more. If, in loading, a space is left
between the wadding and the charge, the gun either recoils
violently, or bursts. If the muzzle of a gun has accidentally
been stuck into the ground, so as to be stopped up with clay, or
even with snow, or if it be fired with its muzzle plunged into
water, the almost certain result is that it bursts.