260 
What  the  Atmosphere  is  Made  of. 
Am.  Jour.  Pliarm. 
June,  1913. 
argon  is  a  component  not  of  the  atmosphere  alone  but  is  contained 
in  various  earthy  products. 
With  reference  to  the  combination  of  argon  with  other  sub- 
stances, the  possible  range  was  carefully  tried  out.  The  speaker 
named  a  score  of  active  agents  to  which  it  was  inert,  the  line  was 
passed  where  gold  is  no  longer  resistant  to  change  and  then  the 
limit  for  platinum.  Argon  was  not  affected  by  electric  sparking 
nor  by  fluorine,  which  is  of  great  activity  in  making  combinations. 
Then  the  fierce  energy  of  the  electric  arc  was  tried  and  at  the 
other  end  of  the  thermal  scale,  liquid  air.  From  all  of  these  tests 
argon  emerged  unchanged  and  undiminished  and  the  distinguished 
lecturer  said,  in  concluding  this  part  of  his  series  of  topics,  "  It 
may  be  possible  to  make  a  combination  with  argon,  but  in  the  light 
of  knowledge  to-day  it  is  difficult  to  see  how  it  can  be  done."  The 
making  of  argon  was  one  of  the  experiments  of  the  evening  of  this 
lecture. 
The  story  of  helium  was  begun  by  Sir  William  at  a  number 
of  different  points.  First  there  was  related  an  outline  of  what 
was  done  by  Doctor  Hillebrand  of  the  United  States  Geological 
Survey,  who  in  heating  some  of  the  compounds  of  uranium — a 
rare  element — found  a  gas  whose  spectrum  was  unknown  to  him. 
Janssen,  the  great  French  astronomer,  during  the  solar  eclipse  in 
India,  obtained  with  the  comparatively  new  spectroscope  a  spectrum 
having  a  bright  yellow  line.  The  great  English  spectroscopists 
tried  to  place  this  and  finally  the  world  came  to  the  realization  that 
it  was  a  new  gas  and  it  was  named  helium.  Sir  William  Ramsay 
secured  from  Doctor  Hillebrand  some  specimens  of  his  mineral, 
cleveite,  for  experiment  and  soon  saw  that  the  spectrum  was  not 
that  of  sodium  which  also  has  a  bright  yellow  line.  Taking  it  to 
Sir  William  Crookes,  who  was  better  fitted  out  with  spectroscopic 
apparatus,  the  latter  viewed  the  spectrum  and  pronounced  it  to  be 
that  of  helium,  then  first  identified  from  earthy  materials.  The 
next  thing,  of  course,  was  to  find  out  by  what  it  could  be  produced 
in  larger  quantities.  "  The  proverbial  needle  in  the  haymow  was 
simplicity  itself,"  said  the  lecturer,  "  compared  with  this  task,"  and 
the  outlining  of  what  was  done  in  the  research  is  testimony  to  the 
splendid  resources  of  the  great  Englishman,  or  rather  Scotchman. 
The  British  Museum  was  ransacked  for  minerals  and  about  two 
hundred  likely  samples  were  taken.  These  were  subjected  to  tests, 
but  no  new  spectrum  resulted;  then  the  gases  of  mineral  waters 
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