﻿Gases 
  of 
  the 
  Helium 
  Group 
  in 
  Minerals. 
  

  

  673 
  

  

  contained 
  in 
  the 
  mineral, 
  a 
  result 
  which 
  Prof. 
  Strutt 
  has 
  failed 
  

   to 
  confirm 
  *. 
  The 
  experiments 
  described 
  in 
  this 
  paper 
  were 
  

   desioned 
  with 
  the 
  intention 
  of 
  obtaining 
  gome 
  evidence 
  on 
  

   the 
  subject 
  which 
  may 
  be 
  considered 
  conclusive. 
  The 
  great 
  

   source 
  of 
  error 
  likely 
  to 
  occur 
  in 
  dealing 
  with 
  argon 
  is 
  by 
  

   contamination 
  of 
  the 
  gas 
  with 
  air, 
  and 
  the 
  apparatus 
  used 
  

   was 
  constructed 
  to 
  eliminate 
  the 
  possibility 
  of 
  this 
  error. 
  

   The 
  liberation, 
  purification, 
  and 
  examination 
  of 
  the 
  gas 
  took 
  

   place 
  in 
  the 
  same 
  tube, 
  from 
  which 
  air 
  was 
  entirely 
  excluded. 
  

   The 
  apparatus 
  shown 
  in 
  fig. 
  1 
  was 
  exhausted 
  until 
  only 
  a 
  

  

  Fio-. 
  1. 
  

  

  - 
  — 
  Spedroscope 
  

  

  a. 
  Hard 
  glass 
  tube 
  contaiDiiig 
  mineral 
  and 
  copper 
  oxide. 
  

   h. 
  Phosphoric 
  oxide 
  to 
  absorb 
  moisture, 
  

   r. 
  Tnlet 
  tube 
  for 
  air. 
  Volume 
  between 
  taps 
  O'lO 
  c.c. 
  

   d. 
  Vacuum-tube. 
  

   e-e. 
  Bulbs 
  containing 
  liquid 
  alloy 
  of 
  sodium 
  and 
  potassium. 
  

  

  very 
  feeble 
  discharge 
  would 
  pass 
  through 
  the 
  vacuum-tube, 
  

   showing 
  a 
  faint 
  spectrum 
  of 
  hydrogen. 
  (The 
  hydrogen 
  was 
  

   probably 
  due 
  to 
  decomposition 
  of 
  the 
  hydroxides 
  of 
  sodium 
  

   and 
  potassium, 
  formed 
  in 
  sealing 
  on 
  the 
  bulbs 
  containing 
  the 
  

   electrodes, 
  or 
  from 
  the 
  glass 
  itself.) 
  The 
  pump 
  was 
  closed 
  

   when 
  it 
  seemed 
  certain 
  that 
  nothing 
  but 
  hydrogen 
  remained 
  

  

  * 
  The 
  Hon. 
  R. 
  J. 
  Strutt, 
  Proceedings 
  Rov. 
  Soc. 
  A. 
  vol. 
  Ixxx. 
  1908, 
  note 
  

   p. 
  593. 
  

  

  