78 THE KINGDOM OF MAN 



enough for this observation ; the lines given by radium 

 are caused by no other known element in heaven or 

 earth. They prove its title to be entered on the roll-call 

 of elements. 



The atomic weight was determined in the usual way 

 by precipitating the chlorine in a solution of radium 

 chloride by means of silver. None of the precious ele- 

 ment was lost in the process, but the Curies never had 

 enough of it to venture on any attempt to prepare 

 pure metallic radium. This is a piece of extravagance 

 no one has yet dared to undertake. Altogether the 

 Curies did not have more than some four or five grains 

 of chloride of radium to experiment with, and the total 

 amount prepared and now in the hands of scientific 

 men in various parts of the world probably does not 

 amount to more than sixty grains at most. When 

 Professor Curie lectured on radium four years ago at 

 the Royal Institution in London he made use of a small 

 tube an inch long and of one-eighth bore, containing 

 nearly the whole of his precious store, wrenched by 

 such determined labour and consummate skill from tons 

 of black shapeless pitch-blende. On his return to Paris 

 he was one day demonstrating in his lecture room with 

 this precious tube the properties of radium when it 

 slipped from his hands, broke, and scattered far and 

 wide the most precious and magical powder ever dreamed 

 of by alchemist or artist of romance. Every scrap of 

 dust was immediately and carefully collected, dissolved, 

 and re-crystallized, and the disaster averted with a loss 

 of but a minute fraction of the invaluable product. 



Thus, then, we have arrived at the discovery of 

 radium the new element endowed in an intense form 

 with the new property * radio-activity ' discovered by 

 Becquerel. The wonder of this powder, incessantly and 



