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  Rayleigh 
  and 
  Ramsay 
  — 
  Argon, 
  a 
  New 
  

  

  absorbent. 
  The 
  elements 
  which 
  have 
  been 
  found 
  to 
  combine 
  

   directly 
  with 
  nitrogen 
  are 
  : 
  boron, 
  silicon, 
  titanium, 
  lithium, 
  

   strontium, 
  barium, 
  magnesium, 
  aluminium, 
  mercury, 
  and, 
  under 
  

   the 
  influence 
  of 
  an 
  electric 
  discharge, 
  hydrogen 
  in 
  presence 
  of 
  

   acid, 
  and 
  oxygen 
  in 
  presence 
  of 
  alkali. 
  Besides 
  these, 
  a 
  mix- 
  

   ture 
  of 
  barium 
  carbonate 
  and 
  carbon 
  at 
  a 
  high 
  temperature 
  is 
  

   known 
  to 
  be 
  effective. 
  Of 
  those 
  tried, 
  magnesium 
  in 
  the 
  

   form 
  of 
  turnings 
  was 
  found 
  to 
  be 
  the 
  best. 
  When 
  nitrogen 
  is 
  

   passed 
  over 
  magnesium, 
  heated 
  in 
  a 
  tube 
  of 
  hard 
  glass 
  to 
  

   bright 
  redness, 
  combustion 
  with 
  incandescence 
  begins 
  at 
  the 
  

   end 
  of 
  the 
  tube 
  through 
  which 
  the 
  gas 
  is 
  introduced, 
  and 
  pro- 
  

   ceeds 
  regularly 
  until 
  all 
  the 
  metal 
  has 
  been 
  converted 
  into 
  

   nitride. 
  Between 
  7 
  and 
  8 
  liters 
  of 
  nitrogen 
  Can 
  be 
  absorbed 
  

   in 
  a 
  single 
  tube 
  ; 
  the 
  nitride 
  formed 
  is 
  a 
  porous, 
  dirty, 
  orange- 
  

   colored 
  substance. 
  

  

  IV. 
  Early 
  Experiments 
  on 
  sparking 
  Nitrogen 
  with 
  Oxygen 
  in 
  

   presence 
  of 
  Alkali. 
  

  

  In 
  our 
  earliest 
  attempts 
  to 
  isolate 
  the 
  suspected 
  gas 
  by 
  the 
  

   method 
  of 
  Cavendish, 
  we 
  used 
  a 
  Ruhmkorff 
  coil 
  of 
  medium 
  

   size 
  actuated 
  by 
  a 
  battery 
  of 
  five 
  Grove 
  cells. 
  The 
  gases 
  were 
  

   contained 
  in 
  a 
  test-tube 
  standing 
  over 
  a 
  large 
  quantity 
  of 
  weak 
  

   alkali, 
  and 
  the 
  current 
  was 
  conveyed 
  in 
  wires 
  insulated 
  by 
  

   U 
  -shaped 
  glass 
  tubes 
  passing 
  through 
  the 
  liquid 
  round 
  the 
  

   mouth 
  of 
  the 
  test-tube. 
  With 
  the 
  given 
  battery 
  and 
  coil 
  a 
  

   somewhat 
  short 
  spark 
  or 
  arc 
  of 
  about 
  5 
  mm 
  was 
  found 
  to 
  be 
  

   more 
  favorable 
  than 
  a 
  longer 
  one. 
  When 
  the 
  mixed 
  gases 
  

   were 
  in 
  the 
  right 
  proportion 
  the 
  rate 
  of 
  absorption 
  was 
  about 
  

   30 
  ec 
  per 
  hour, 
  or 
  thirty 
  times 
  as 
  fast 
  as 
  Cavendish 
  could 
  work 
  

   with 
  the 
  electrical 
  machine 
  of 
  his 
  day. 
  

  

  To 
  take 
  an 
  example, 
  one 
  experiment 
  of 
  this 
  kind 
  started 
  

   with 
  50 
  cc 
  of 
  air. 
  To 
  this 
  oxygen 
  was 
  gradually 
  added 
  until, 
  

   oxygen 
  being 
  in 
  excess, 
  there 
  was 
  no 
  perceptible 
  contraction 
  

   during 
  an 
  hour's 
  sparking. 
  The 
  remaining 
  gas 
  was 
  then 
  trans- 
  

   ferred 
  at 
  the 
  pneumatic 
  trough 
  to 
  a 
  small 
  measuring 
  vessel, 
  

   sealed 
  by 
  mercury, 
  in 
  which 
  the 
  volume 
  was 
  found 
  to 
  be 
  1-0 
  CC 
  . 
  

   On 
  treatment 
  with 
  alkaline 
  pyrogallate, 
  the 
  gas 
  shrank 
  to 
  0*32 
  cc 
  . 
  

   That 
  this 
  small 
  residue 
  could 
  not 
  be 
  nitrogen 
  was 
  argued 
  from 
  

   the 
  fact 
  that 
  it 
  had 
  withstood 
  the 
  prolonged 
  action 
  of 
  the 
  

   spark, 
  although 
  mixed 
  with 
  oxygen 
  in 
  nearly 
  the 
  most 
  favor- 
  

   able 
  proportion. 
  

  

  The 
  residue 
  was 
  then 
  transferred 
  to 
  the 
  test-tube 
  with 
  an 
  

   addition 
  of 
  another 
  50 
  cc 
  of 
  air, 
  and 
  the 
  whole 
  worked 
  up 
  with 
  

   oxygen 
  as 
  before. 
  The 
  residue 
  was 
  now 
  2*2 
  CC 
  , 
  and, 
  after 
  

   removal 
  of 
  oxygen, 
  0"76 
  cc 
  . 
  

  

  