4'62 Modifications of Hydrogen and Nitrogen by u Rays. 



gas. Some of the atoms will be formed at the surface of 

 the element, and will react chemically. Others will be pro- 

 duced in the interior of the gas, and will form triatomic 

 molecules by collision with the neutral molecules. The 

 primary action of the a rays appears to be the liberation of 

 atoms of high activity. In addition, the rays produce S rays 

 by their motion through gases, and these $ rays may also be 

 effective in producing the active modifications. The chemical 

 actions occurring are probably determined by the heat neces- 

 sary to effect the decomposition of the molecules, and not by 

 the heat required for the final transformations and resulting 

 products. That the a rays produce active modifications of 

 hydrogen and nitrogen, which in turn are able to react 

 chemically with certain elements, strengthens the view 

 that the disappearance of these gases in an electric discharge 

 tube, in the presence of various elements, is also due mainly 

 to the formation of the active modifications of the gases by 

 the electric discharge. 



7. Summary. 



1. a rays from polonium were allowed to act on nitrogen 

 at different pressures in the presence of various elements. 

 Some of the gas was absorbed. 



2. The elements tested were sodium, potassium, sulphur, 

 phosphorus, iodine, magnesium, arsenic, mercury, together 

 with the alloy of sodium and potassium. Similar experi- 

 ments with hydrogen gave absorption with sulphur, phos- 

 phorus, and iodine. 



3. The absorption of the gas was shown to be due to 

 chemical action resulting in the production of nitrides and 

 hydrides. 



4. The chemical activity of the gas is due to an active 

 modification produced by the a rays. The active form, 

 probably consisting of neutral atoms and triatomic molecules, 

 is not due directly to the presence of ions. 



5. The a. rays are the only ones effective from radioactive 

 bodies. 





