INTRA-ATOMIC ENERGY. 177 



mously exceed this amount. We have already shown that 

 Professor Thomson's calculations have a habit of squaring 

 with fact. The energy whence we obtain our manufactur- 

 ing power whether derived from burning coal or gas or any 

 other chemical reaction depends upon the action of one sys- 

 tem of atoms upon another. It is absolutely insignificant 

 compared with the limitless energy .locked up within the 

 atoms themselves. We know that this energy exists, but, 

 to-day, we have no control over it. We can neither set it 

 loose nor tie it up in any way whatever. We can only 

 observe it. But it would be rash indeed to predict that our 

 impotence will last forever. Strange things happen nowa- 

 days and yet stranger things may, nay will, be seen by 

 future men. We have no real warranty that this infinity 

 of energy will be tapped by man, except this : That what 

 man earnestly longs for he will obtain. If he knows that 

 every breath of air he draws has contained within itself 

 power enough to drive the workshops of the world he will 

 find out some day, seme how, some way of tapping that 

 energy. In looking for plausible methods of attacking 

 the problem we find at least a hint. X-rays passing 

 through a substance cause it to emit X-rays. These 

 induced X-rays are called secondary rays or the S-rays cf 

 Sagnac. They are emitted from solids, liquids and gases 

 whenever X-rays fall upon them, and they differ in charac- 

 ter from the primary rays that produce them. They are 

 not pure X-rays for they consist of corpuscles as well, and 

 since some of the radiation is exceedingly easily absorbed, 

 it is likely that alpha particles are present also. If this is 

 the case it is difficult to see why we should not call a body 

 lying under the impact of X-rays, radio-active ; and if the 

 body becomes radio-active in this way, it is a moot point, 

 indeed, as to whether the energy of the radiating substance 

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