﻿Constituent 
  of 
  the 
  Atmosphere. 
  291 
  

  

  The 
  presence 
  of 
  a 
  small 
  quantity 
  of 
  nitrogen 
  interferes 
  

   greatly 
  with 
  the 
  argon 
  spectrum. 
  But 
  we 
  have 
  found 
  that 
  in 
  

   a 
  tube 
  with 
  platinum 
  electrodes, 
  after 
  the 
  discharge 
  has 
  been 
  

   passed 
  for 
  four 
  hours, 
  the 
  spectrum 
  of 
  nitrogen 
  disappears, 
  and 
  

   the 
  argon 
  spectrum 
  manifests 
  itself 
  in 
  full 
  purity. 
  A 
  specially 
  

   constructed 
  tube 
  with 
  magnesium 
  electrodes, 
  which 
  we 
  hoped 
  

   would 
  yield 
  good 
  results, 
  removed 
  all 
  traces 
  of 
  nitrogen, 
  it 
  is 
  

   true; 
  but 
  hydrogen 
  was 
  evolved 
  from 
  the 
  magnesium, 
  and 
  

   showed 
  its 
  characteristic 
  lines 
  very 
  strongly. 
  However, 
  these 
  

   are 
  easily 
  identified. 
  The 
  gas 
  evolved 
  on 
  heating 
  magnesium 
  

   in 
  vacuo, 
  as 
  proved 
  by 
  a 
  separate 
  experiment, 
  consists 
  entirely 
  

   of 
  hydrogen. 
  

  

  Mr. 
  Crookes 
  has 
  proved 
  the 
  identity 
  of 
  the 
  chief 
  lines 
  of 
  the 
  

   spectrum 
  of 
  gas 
  separated 
  from 
  air-nitrogen 
  by 
  aid 
  of 
  magne- 
  

   sium 
  with 
  that 
  remaining 
  after 
  sparking 
  the 
  air-nitrogen 
  with 
  

   oxygen 
  in 
  presence 
  of 
  caustic 
  soda 
  solution. 
  

  

  Professor 
  Schuster 
  also 
  has 
  found 
  the 
  principal 
  lines 
  identi- 
  

   cal 
  in 
  the 
  spectra 
  of 
  the 
  two 
  gases, 
  as 
  observed 
  by 
  the 
  jar 
  dis- 
  

   charge 
  at 
  atmospheric 
  pressure. 
  

  

  XII. 
  /Solubility 
  of 
  Argon 
  in 
  Water. 
  

  

  Determinations 
  of 
  the 
  solubility 
  in 
  water 
  of 
  argon, 
  prepared 
  

   by 
  sparking, 
  gave 
  3*94 
  volumes 
  per 
  100 
  of 
  water 
  at 
  12°. 
  The 
  

   solubility 
  of 
  gas 
  prepared 
  by 
  means 
  of 
  magnesium 
  was 
  found 
  

   to 
  be 
  4*05 
  volumes 
  per 
  100 
  at 
  13*9°. 
  The 
  gas 
  is 
  therefore 
  

   about 
  2 
  J 
  times 
  as 
  soluble 
  as 
  nitrogen, 
  and 
  possesses 
  approxi- 
  

   mately 
  the 
  same 
  solubility 
  as 
  oxygen. 
  

  

  The 
  fact 
  that 
  argon 
  is 
  more 
  soluble 
  than 
  nitrogen 
  would 
  

   lead 
  us 
  to 
  expect 
  it 
  in 
  increased 
  proportion 
  in 
  the 
  dissolved 
  

   gases 
  of 
  rain 
  water. 
  Experiment 
  has 
  confirmed 
  this 
  anticipa- 
  

   tion. 
  "Nitrogen" 
  prepared 
  from 
  the 
  dissolved 
  gases 
  of 
  water 
  

   supplied 
  from 
  a 
  rain-water 
  cistern 
  was 
  weighed 
  upon 
  two 
  

   occasions. 
  The 
  weights, 
  corresponding 
  to 
  those 
  recorded 
  in 
  

   § 
  I, 
  were 
  2*3221 
  and 
  2*3227, 
  showing 
  an 
  excess 
  of 
  24 
  milli- 
  

   grams 
  above 
  the 
  weight 
  of 
  true 
  nitrogen. 
  Since 
  the 
  corre- 
  

   sponding 
  excess 
  for 
  " 
  atmospheric 
  nitrogen 
  " 
  is 
  11 
  milligrams, 
  

   we 
  conclude 
  that 
  the 
  water 
  " 
  nitrogen 
  " 
  is 
  relatively 
  more 
  than 
  

   twice 
  as 
  rich 
  in 
  argon. 
  

  

  On 
  the 
  other 
  hand, 
  gas 
  evolved 
  from 
  the 
  hot 
  spring 
  at 
  Bath, 
  

   and 
  collected 
  for 
  us 
  by 
  Dr. 
  A. 
  Richardson, 
  gave 
  a 
  residue 
  after 
  

   removal 
  of 
  oxygen 
  and 
  carbonic 
  acid, 
  whose 
  weight 
  was 
  only 
  

   about 
  midway 
  between 
  that 
  of 
  true 
  -and 
  atmospheric 
  nitrogen. 
  

  

  XIII. 
  Behavior 
  at 
  Low 
  Temperatures.* 
  

   Preliminary 
  experiments, 
  carried 
  out 
  to 
  liquefy 
  argon 
  at 
  a 
  

   pressure 
  of 
  about 
  100 
  atmospheres, 
  and 
  at 
  a 
  temperature 
  of 
  

  

  * 
  The 
  arrangements 
  for 
  the 
  experiments 
  upon 
  this 
  branch 
  of 
  the 
  subject 
  were 
  

   left 
  entirely 
  in 
  Professor 
  Ramsay's 
  hands. 
  

  

  