﻿Constituent 
  of 
  the 
  Atmosphere. 
  281 
  

  

  by 
  being 
  united 
  to 
  phlogiston, 
  is 
  converted 
  into 
  air 
  possessed 
  

   of 
  these 
  properties, 
  and 
  consequently, 
  though 
  it 
  was 
  reasonable 
  

   to 
  suppose, 
  that 
  part 
  at 
  least 
  of 
  the 
  phlogisticated 
  air 
  of 
  the 
  

   atmosphere 
  consists 
  of 
  this 
  acid 
  united 
  to 
  phlogiston, 
  yet 
  it 
  

   was 
  fairly 
  to 
  be 
  doubted 
  whether 
  the 
  whole 
  is 
  of 
  this 
  kind, 
  or 
  

   whether 
  there 
  are 
  not 
  in 
  reality 
  many 
  different 
  substances 
  com- 
  

   pounded 
  together 
  by 
  us 
  under 
  the 
  name 
  of 
  phlogisticated 
  air. 
  

   I 
  therefore 
  made 
  an 
  experiment 
  to 
  determine 
  whether 
  the 
  

   whole 
  of 
  a 
  given 
  portion 
  of 
  the 
  phlogisticated 
  air 
  of 
  the 
  

   atmosphere 
  could 
  be 
  reduced 
  to 
  nitrous 
  acid, 
  or 
  whether 
  there 
  

   was 
  not 
  a 
  part 
  of 
  a 
  different 
  nature 
  to 
  the 
  rest, 
  which 
  would 
  

   refuse 
  to 
  undergo 
  that 
  change. 
  The 
  foregoing 
  experiments 
  

   indeed 
  in 
  some 
  measure 
  decided 
  this 
  point, 
  as 
  much 
  the 
  greatest 
  

   part 
  of 
  the 
  air 
  let 
  up 
  into 
  the 
  tube 
  lost 
  its 
  elasticity 
  ; 
  yet 
  as 
  

   some 
  remained 
  unabsorbed 
  it 
  did 
  not 
  appear 
  for 
  certain 
  whether 
  

   that 
  was 
  of 
  the 
  same 
  nature 
  as 
  the 
  rest 
  or 
  not. 
  For 
  this 
  pur- 
  

   pose 
  I 
  diminished 
  a 
  similar 
  mixture 
  of 
  dephlogisticated 
  and 
  

   common 
  air, 
  in 
  the 
  same 
  manner 
  as 
  before, 
  till 
  it 
  was 
  reduced 
  

   to 
  a 
  small 
  part 
  of 
  its 
  original 
  bulk. 
  I 
  then, 
  in 
  order 
  to 
  decom- 
  

   pound 
  as 
  much 
  as 
  I 
  could 
  of 
  the 
  phlogisticated 
  air 
  which 
  

   remained 
  in 
  the 
  tube, 
  added 
  some 
  dephlogisticated 
  air 
  to 
  it, 
  

   and 
  continued 
  the 
  spark 
  until 
  no 
  further 
  diminution 
  took 
  

   place. 
  Having 
  by 
  these 
  means 
  condensed 
  as 
  much 
  as 
  I 
  could 
  

   of 
  the 
  phlogisticated 
  air, 
  I 
  let 
  up 
  some 
  solution 
  of 
  liver 
  of 
  

   sulphur 
  to 
  absorb 
  the 
  dephlogisticated 
  air 
  ; 
  after 
  which 
  only 
  a 
  

   small 
  bubble 
  of 
  air 
  remained 
  unabsorbed, 
  which 
  certainly 
  was 
  

   not 
  more 
  than 
  y^^th 
  of 
  the 
  bulk 
  of 
  the 
  phlogisticated 
  air 
  let 
  up 
  

   into 
  the 
  tube 
  ; 
  so 
  that 
  if 
  there 
  is 
  any 
  part 
  of 
  the 
  phlogisticated 
  

   air 
  of 
  our 
  atmosphere 
  which 
  differs 
  from 
  the 
  rest, 
  and 
  cannot 
  

   be 
  reduced 
  to 
  nitrous 
  acid, 
  we 
  may 
  safely 
  conclude 
  that 
  it 
  is 
  

   not 
  more 
  than 
  y^th 
  part 
  of 
  the 
  whole." 
  

  

  Although 
  Cavendish 
  was 
  satisfied 
  with 
  his 
  result, 
  and 
  does 
  

   not 
  decide 
  whether 
  the 
  small 
  residue 
  was 
  genuine, 
  our 
  experi- 
  

   ments 
  about 
  to 
  be 
  related 
  render 
  it 
  not 
  improbable 
  that 
  his 
  

   residue 
  was 
  really 
  of 
  a 
  different 
  kind 
  from 
  the 
  main 
  bulk 
  of 
  

   the 
  " 
  phlogisticated 
  air," 
  and 
  contained 
  the 
  gas 
  now 
  called 
  

   argon. 
  

  

  Cavendish 
  gives 
  data* 
  from 
  which 
  it 
  is 
  possible 
  to 
  determine 
  

   the 
  rate 
  of 
  absorption 
  of 
  the 
  mixed 
  gases 
  in 
  his 
  experiment. 
  

   This 
  was 
  about 
  l 
  cc 
  per 
  hour, 
  of 
  which 
  two-fifths 
  would 
  be 
  

   nitrogen. 
  

  

  III. 
  Methods 
  of 
  causing 
  Free 
  Nitrogen 
  to 
  combine. 
  

  

  To 
  eliminate 
  nitrogen 
  from 
  air, 
  in 
  order 
  to 
  ascertain 
  whether 
  

   any 
  other 
  gas 
  could 
  be 
  detected, 
  involves 
  the 
  use 
  of 
  some 
  

  

  *Phil. 
  Trans., 
  vol. 
  lxxviii, 
  p. 
  271, 
  1788. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Third 
  Series, 
  Vol. 
  XLIX, 
  No. 
  292.— 
  April, 
  1895. 
  

   19 
  

  

  