Am.  Jour.  Pharm. ) 
April,  1909.  J 
A  Piece  of  Pitchblende. 
Ramsay  has  aptly  summed  up  its  character ;  for  it  differs  in  many 
respects  from  all  other  forms  of  matter,  and  is  capable  of  producing 
most  wonderful  effects  on  other  bodies. 
Unlike  the  radiations,  the  emanation  is  scarcely  given  off  by 
radium  compounds  in  dry  air,  but  is  released  from  them  when  they 
are  heated  or  dissolved  in  water.  In  the  latter  case  the  water  is 
decomposed  in  a  similar  way  as  by  an  electric  current,  yielding  up 
bubbles  of  gas.  This  gas  is  a  mixture  of  oxygen  and  hydrogen,  very 
nearly  in  the  proportions  in  which  these  elements  exist  in  water,  but 
it  contains  in  addition  a  minute  amount  of  the  emanation.  When 
the  gas  is  placed  in  a  tube  surrounded  by  liquid  air  and  thus  cooled  to 
say  3560  F.,  the  emanation  condenses  or  freezes  to  the  walls  of  the 
tube,  while  the  other  gases  can  be  removed  by  means  of  an  air- 
pump.  Upon  raising  the  temperature  of  the  tube,  the  emanation 
turns  into  gas  again,  but  its  volume  is  so  small  that  it  must  be 
collected  in  a  vessel  of  exceedingly  fine  bore.  Ramsay  estimates  that 
one  grain  of  radium  bromide  yields  about  one  thirty  thousandth 
cubic  centimetre  of  this  gas  per  week. 
You  will  see  from  this  what  enormous  difficulties  must  have  been 
encountered  in  experimenting  with  the  radium  emanation;  yet  the 
results  which  have  already  been  obtained  are  quite  sufficient  fully 
to  repay  the  investigators  for  their  great  sacrifices  of  labor,  time 
and  expense. 
There  cannot  be  the  slightest  doubt  that  the  emanation  is  a 
gaseous  substance.  Not  only  has  it  been  collected  and  measured, 
but  it  has  also  been  shown  to  obey  the  simple  laws  that  govern  the 
effects  of  pressure  and  temperature  upon  gases.  Moreover,  it 
freely  diffuses  through  other  gases,  such  as  air,  and,  as  already 
stated,  condenses  to  a  liquid  or  solid  at  very  low  temperatures.  The 
emanation  glows  in  the  dark ;  its  spectrum  shows  characteristic 
bright  lines,  recalling  the  spectra  of  the  argon  group  of  inert  gases. 
Its  density  is  estimated  to  be  about  100  times  that  of  hydrogen. 
Like  argon  and  its  congeners,  the  emanation  is  not  acted  upon 
by  the  most  powerful  of  chemical  agencies.  It  appears  to  be 
chemically  inert,  and  probably  belongs  to  the  argon  group  of  ele- 
ments. But,  although  devoid  of  such  chemical  affinities  as  are 
manifested  in  the  chemical  changes  with  which  we  are  familiar,  it 
nevertheless  produces  most  remarkable  chemical  effects  upon  other 
substances.  This  is  due  to  its  enormous  radio-active  power. 
Weight  for  weight  it  is  estimated  that  the  radium  gas  is  100,000 
