ms have rushed together with detonation,
and without injury to my hand, and the water from which they were
extracted is the result of their re-union.

*****

One consequence of the rushing together of the atoms is the
development of heat. What is this heat? Here are two ivory balls
suspended from the same point of support by two short strings. I draw
them thus apart and then liberate them. They clash together, but, by
virtue of their elasticity, they quickly recoil, and a sharp vibratory
rattle succeeds their collision. This experiment will enable you to
figure to your mind a pair of clashing atoms. We have in the first
place, a motion of the one atom towards the other--a motion of
translation, as it is usually called--then a recoil, and afterwards a
motion of vibration. To this vibratory motion we give the name of
heat. Thus, three things are to be kept before the mind--first, the
atoms themselves; secondly, the force with which they attract each
other; and thirdly, the motion consequent upon the exertion of that
force. This motion must be figured first as a motion of translation,
and then as a motion of vibration, to which latter we give the name of
heat. For some time after the act of combination this motion is so
violent as to prevent the molecules from coming together, the water
being maintained in a state of vapour. But as the vapour cools, or in
other words loses its motion, the molecules coalesce to form a liquid.

And now we approach a new and wonderful display of force. As long as
the substance remains in a liquid or vaporous condition, the play of
this force is altogether masked and bidden. But as the heat is
gradually withdrawn, the molecules prepare for new arrangements and
combinations. Solid crystals of water are at length formed, to which
we give the familiar name of ice. Looking at these beautiful edifices
and their internal structure, the pondering mind has forced upon it
the question, How are they built up? We have obtained clear
conceptions of polar force; and we infer from our broken magnet that
polar force may be resident in the molecules or smallest particles of
matter, and that by the play of this force structural arrangement is
possible. What, in relation to our present question, is the natural
action of a mind furnished with this knowledge? It is compelled to
transcend experience, and endow the atoms and molecules of which
crystals are built with definite poles whence issue