URANIUM 

 5.OOO.OOO.OOO. YEARS 



URANIUM X 

 23-5 DAYS 



RADIUM 



1.730 YEARS 



RADIUM EMANATION 

 3-ftS DAYS 



RADIUM A 

 3 MIN5. 



RADIUM B 

 26 Q MINS. 



POLONIUM 

 136 DAYS 



LEAD? 



DISINTEGRATION OF ATOMS 



An atom of Uranium, by ejecting an Alpha particle, becomes Uranium X. This substance, by ejecting Bet* and Gamma ray*. 

 becomes Radium. Radium passes through a number of further changes, as shown in the diagram, and finally becomes lead. Some 

 radio active substances disintegrate much faster than others. Thus Uranium changes very slowly, taking 5,000,000.000 yean to reach 

 the same stage of disintegration that Radium A reaches in 3 minutes. As the disintegration proceeds, the substance* become of lighter 

 and lighter atomic weights. Thus Uranium has an atomic weight of 238, whereas lead has an atomic weight of only zoo. The break- 

 ing down of atoms is fully explained in the text. 



Reproduced by permission from "The Interpretation of 

 Radium" (John Murray). 



SILK TASSEL ELECTRIFIED 



The separate threads of the tassel, being each electrified 

 with the same kind of electricity, repel one another, and thus 

 the tassel branches out as in the photograph. 



SILK TASSEL DISCHARGED BY THE RAYS FROM 

 RADIUM 



When the radium rays, carrying an opposite electric charge 

 to that on the tassel, strikes the threads, the thread* are 

 neutralised, and hence fall together again. 



