92 THE NEW KNOWLEDGE. 



is possible, by the methods of ordinary chemical analysis, to 

 extract from pitchblende substances, of which the radio- 

 activity is in the neighborhood of 100,000 times greater than 

 that of metallic uranium." 



In this simple manner did the Curies announce their dis- 

 covery of three new elements with transcendent ray-emitting 

 powers radium, polonium, and actinium which they dis- 

 covered with Debierne. Since that time others have been 

 discovered. Of these strangers in the world of matter, we 

 shall select radium as our first object of study, as it is the 

 most easily obtained. Its discovery, with its ray-emitting 

 power 100,000 times greater than uranium, placed in the 

 hands of investigators a mighty engine of research for deter- 

 mining the properties of Becquerel rays. 





