94 UNIVERSITY OF MISSOURI BULLETIN 



"Matter (substance) is composed chiefly of holes. We 

 may in fact regard matter (substance) as possessing a bird- 

 cage kind of structure." 



To return to "radiant matter," the properties mentioned 

 have been studied mostly with electrons and positively charged 

 particles experimentally produced, but there are in the so- 

 called radio-active elements, along with other charged par- 

 ticles, the negative electrons, "corpuscles," and the positively 

 charged a particles. The ^ rays of radium are negatively 

 electrified corpuscles and the a rays positively charged atoms 

 of helium. The discovery of this character of the a rays, 

 charged atoms of helium, is largely due to the energy and 

 inventiveness of Rutherford. These radiations are produced 

 during or by the breaking up of the atoms producing them 

 into atoms of lower atomic weight, thus the atoms of uranium 

 for example slowly breaking up, one of the products being 

 radium, while radium breaks up in the way just mentioned. 

 The atoms of the radio-active elements are not immortal ; 

 they perish after a life whose average value ranges from 

 thousands of millions of years in the case of uranium to a 

 second or so in the case of the gaseous emanation from 

 actinium. 



When atoms pass from one state to another they give 

 out vast stores of energy. The percentage of atoms which 

 disappear in one second is always the same. Why do these 

 atoms break down, disintegrate? The evidence at present is 

 against the view that a disturbance from the outside breaks 

 down the radio-active atoms; there is some process of decay 

 in the atom itself. The energy developed by radio-active sub- 

 stances is exceedingly large, one gramme of radium develop- 

 ing nearly as much energy as would be produced in burning 

 a ton of coal. This energy is mainly in the a particles, the 

 positively charged helium atoms which are emitted when the 

 destruction of the atom takes place. The source of this 

 energy is a problem of the deepest interest. One method by 



