Am.  Jour.  Pharni.") 
April,  1909.  J 
A  Piece  of  Pitchblende. 
167 
minerals  could  be  accounted  for,  was  to  assume  that  they  contained 
some  unknown  substance  of  extraordinary  radio-active  power. 
But  how  could  this  hidden  constituent  be  brought  to  light? 
Chemists  had  apparently  exhausted  their  analytical  resources  in  the 
study  of  pitchblende,  the  mineral  which  headed  Mme.  Curie's  list  of 
radio-active  substances.  Her  fertile  mind,  however,  devised  a  novel 
means  of  searching  for  the  hypothetical  component :  by  introducing 
the  electroscope  into  chemical  analysis,  and  systematically  testing  the 
products  of  chemical  separation  for  their  radio-active  power,  she 
succeeded  in  concentrating  those  intensely  radio-active  substances  in 
certain  minute  fractions  of  material  she  obtained  from  the  ore. 
It  was  evident  now  that  the  extraction,  even  of  small  quantities 
of  the  radio-active  body  or  bodies,  would  require  the  use  of  enormous 
quantities  of  the  costly  pitchblende ;  but  this  difficulty  was  overcome 
by  the  happy  idea  to  experiment  upon  the  uranium  residues  of  which 
such  large  quantities  had  accumulated  at  Joachimsthal.  Mme.  Curie 
and  her  husband,  the  late  Pierre  Curie,  having  ascertained  that  this 
material  contains  practically  all  of  the  radio-active  components  of 
Copyrighted,  1904,  by  William  J.  Hammer. 
Mme.  Sklodowska  Curie 
