10 president's address. 



chJoridc of radium Lo experiment with, and the total {imouufc prepared 

 and now in the hands of scientific men in various parts of the ■world 

 probably does not amount to moi'e than sixty grains at most. When 

 Professor Curie lectured on radium four years ago at the Royal Institu- 

 tion 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 demon- 

 strating 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 without loss, under any and all conditions pouring forth by virtue of 

 its own intrinsic property powerful rays capable of penetrating opaque 

 bodies and of exciting phosphorescence and acting on photographic plates, 

 can perhaps be realised when we reflect that it is as marvellous as though 

 we should dig up a stone which without external influence or change, 

 continually poured forth light or heat, manufacturing both in itself, and 

 not only continuing to do so without appreciable loss or change, but 

 necessarily having always done so for countless ages whilst sunk beyond 

 the ken of man in the bowels of the earth. 



Wonderful as the story is, so far it is really simple and commonplace 

 compared with what yet remains to be told. I will only barely and 

 •abruptly state the fact that radio-activity has been discovered in other 

 elements, some very rare, such as actinium and polonium ; others more 

 abundant and already known, such as thorium and uranium, though 

 their radio-activity was not known until Becquerel's pioneer-discovery. 

 It is a little strange and no doubt significant that, after all, pure uranium 

 is found to have a radio-activity of its own and not to have been 

 altogether usurping the rights of its infinitesimal associate. 



The wonders connected with radium really begin when the experi- 

 mental examination of the properties of a few grains is made. What I 

 am saying here is not a systematic, technical account of radium ; so I shall 

 ventui'e to relate some of the story as it impresses me. 



Leaving aside for a moment what has been done in regard to the more 

 precise examination of the rays emitted by radium, the following 

 astonishing facts have been found out in regard to it : (1) If a glass 

 tube containing radium is much handled or kept in the waistcoat pocket, 

 it produces a destruction of the skin and flesh over a small area — in fact, a 

 sore place. (2) The smallest trace of radium brought into a room where 

 a charged electroscope is present, causes the discharge of the electroscope. 



