volcanic eruption manifests the activity of some of them. Think of the
giant power of confined steam; if enough steam could be suddenly
generated in the center of the earth by a downpour of all the waters
of the oceans, what might not the consequences be for our globe? In a
smaller globe, and it has never been estimated that the original
asteroid was even as large as the moon, such a catastrophe would,
perhaps, be more easily conceivable; but since we are compelled in
this case to assume that there was a series of successive explosions,
steam would hardly answer the purpose; it would be more reasonable to
suppose that the cause of the explosion was some kind of chemical
reaction, or something affecting the atoms composing the exploding
body. Here Dr Gustav Le Bon comes to our aid with a most startling
suggestion, based on his theory of the dissipation of intra-atomic
energy. It will be best to quote him at some length from his book on
The Evolution of Forces.

``It does not seem at first sight,'' says Doctor Le Bon,

very comprehensible that worlds which appear more and more stable
as they cool could become so unstable as to afterward dissociate
entirely. To explain this phenomenon, we will inquire whether
astronomical observations do not allow us to witness this
dissociation.

We know that the stability of a body in motion, such as a top or a
bicycle, ceases to be possible when its velocity of rotation
descends below a certain limit. Once this limit is reached it loses
its stability and falls to the ground. Prof. J. J. Thomson even
interprets radio-activity in this manner, and points out that when
the speed of the elements composing the atoms descends below a