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off at frequent intervals. These particles, on account of their high speed, 
have considerable potential energy. Thus the sphere continues to give 
off energy without receiving any as long as any mass remains. The source 
of the energy is the kinetic energy stored in the sphere at the outset, of 
which energy we are conscious only when we have some method of detect- 
ing and slowing down the projected particles. 
Thus the energy radiated by radium might be stored within the ra- 
dium atom as potential energy and liberated by a sort of atomic—or sub- 
atomic—explosion. Or it might be stored as kinetic energy—ot revolving 
electrons—and liberated gradually as these electrons escape from their 
orbits. It might be stored in both forms. In any case it is intra-atomic 
energy because stored within the atom itself and liberated only by atomic 
change—iisintegration. In neither case would there be a violation of the 
principle of the conservation of energy or of the second law of thermo- 
dynamics. Sooner or later all the energy will have been radiated. The 
fact that the supply is destined to last so long is what appeals to us as 
wonderful. And so it is. The world is full of wonderful things to anyone 
who pauses long enough to think. 
In this paper I have endeavored to give a general notion of the trend 
of thought and investigation in physical science rather than an enumera- 
tion and discussion of discoveries and theories. I might say, however, 
that there are strong reasons for believing in the molecular structure of 
electricity the electrical nature of matter, and the dependence of mass upon 
velocity. The theories of radioactivity and disintegration of matter are 
fairly well established. According to Ramsay; one of the most eminent 
chemists in the world, “we are on the brink of discovering the synthesis 
of atoms, which may lead to the discovery of the ordinary elements.” 
Perhaps the dream of the alchemist is about to be realized. Certain it is 
that we are face to face with energies of which no one even dreamed a 
few years ago. Whether we call this energy intra-atomic, sub-atomic, 
interelemental or some other name, we know certainly that it exists, and 
that it exists in quantities far beyond the power of man’s mind to com- 
prehend. Man hopes some day, somewhere, somehow, to discover the 
means of unlocking this infinite storehouse. If this discovery is ever 
made, all the others which man has ever made will pale into insignificance 
beside it. 
Lodge says of the one-pound shot and the one-hundred-pound shot 
which Galileo dropped from the top of the Leaning Tower, that “their 
