SOME PHYSICAL PROBLEMS 



change would be directly proportionate to their radio- 

 activity. Radium, according to the recent estimate 

 of the Curies, would be disintegrating over a million 

 times more rapidly than uranium. Since the amount of 

 transformation occurring in radium in a year amounts 

 to from 1-2000 to 1-10,000 of the total amount, the 

 time required for the complete transformation of an 

 atom of uranium would be somewhere between two 

 billion and ten billion years figures quite beyond the 

 range of human comprehension. 



Various hypotheses have been postulated to account 

 for the instability of the atom. Perhaps the most 

 thinkable of these to persons not specially trained in 

 dealing with abstruse subjects is that of Professor 

 Thompson. It has the additional merit, also, of 

 coming from one of the best-known investigators in 

 this particular field. According to this hypothesis 

 the atom may be considered as a mass of positively 

 and negatively charged particles, all in rapid motion, 

 their mutual forces holding them in equilibrium. In 

 case of a very complex structure of this kind it is possi- 

 ble to conceive of certain particles acquiring sufficient 

 kinetic energy to be projected from the system. Or 

 the constraining forces may be neutralized momen- 

 tarily, so that the particle is thrown off at the same 

 velocity that it had acquired at the instant it is re- 

 leased. The primary cause of this disintegration of the 

 atom may be due to electro-magnetic radiation causing 

 loss of energy of the atomic system. 



Sir Oliver Lodge suggests that this instability of 

 the atom may be the result of the atom's radiation of 

 energy. " Lodge considered the simple case of a nega- 



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