﻿JV. 
  L. 
  Bowen 
  — 
  Sodmim-Potassium 
  Nephelites. 
  117 
  

  

  water 
  in 
  a 
  gold 
  crucible 
  in 
  a 
  steel 
  bomb 
  after 
  the 
  usual 
  

  

  method.* 
  The 
  temperature 
  was 
  kept 
  at 
  600° 
  and 
  the 
  pressure 
  

  

  of 
  water 
  vapor 
  at 
  about 
  1000 
  atmospheres 
  for 
  24 
  hours. 
  

  

  An 
  analysis 
  of 
  the 
  kaliophilite 
  crystals 
  obtained 
  is 
  stated 
  

  

  below. 
  

  

  I 
  II 
  

  

  Si0 
  2 
  _ 
  38-0 
  38-07 
  

  

  A1 
  2 
  0, 
  32-0 
  32-21 
  

  

  K 
  2 
  29-8 
  29-72 
  

  

  H 
  2 
  12 
  .... 
  

  

  99-9 
  10000 
  

  

  I. 
  Artificial 
  kaliophilite. 
  Analyst 
  "N". 
  L. 
  Bowen. 
  

   II. 
  Theoretical 
  composition, 
  KAlSi0 
  4 
  . 
  

  

  The 
  optical 
  properties 
  were 
  exactly 
  as 
  given 
  above. 
  

  

  Formation 
  of 
  leucite, 
  — 
  In 
  attempting 
  to 
  prepare 
  kaliophilite 
  

   by 
  heating 
  glass 
  of 
  composition 
  KAlSi0 
  4 
  at 
  about 
  800° 
  with 
  

   potassium 
  tungstate 
  occasional 
  crystals 
  of 
  kaliophilite 
  were 
  

   obtained 
  but 
  the 
  great 
  bulk 
  of 
  the 
  product 
  was 
  a 
  material 
  of 
  

   weak 
  double 
  refraction 
  and 
  conspicuous 
  polysynthetic 
  twinning. 
  

   The 
  refractive 
  index 
  was 
  1*509. 
  This 
  value, 
  together 
  with 
  the 
  

   polysynthetic 
  twinning, 
  gave 
  the 
  impression, 
  at 
  first, 
  that 
  a 
  

   form 
  of 
  the 
  potash 
  compound 
  corresponding 
  with 
  carnegieite 
  

   had 
  been 
  obtained. 
  These 
  properties 
  agree, 
  however, 
  with 
  

   those 
  of 
  leucite 
  and 
  an 
  occasional 
  crystal 
  suggested 
  the 
  typical 
  

   icositetrahedron 
  of 
  that 
  mineral 
  though 
  the 
  majority 
  of 
  them 
  

   were 
  in 
  branching 
  forms. 
  The 
  amount 
  of 
  material 
  was 
  insuffi- 
  

   cient 
  for 
  analysis 
  so 
  a 
  small 
  portion 
  was 
  converted 
  to 
  glass 
  in 
  

   the 
  oxy-hydrogen 
  flame 
  and 
  the 
  refractive 
  index 
  of 
  the 
  glass 
  

   determined. 
  The 
  index 
  was 
  found 
  to 
  be 
  about 
  1490 
  and 
  to 
  

   correspond 
  with 
  that 
  of 
  glass 
  made 
  by 
  melting 
  leucite 
  from 
  

   Vesuvius 
  whereas 
  the 
  index 
  of 
  glass 
  of 
  composition 
  KAlSi0 
  4 
  

   is 
  1'508. 
  The 
  crystals 
  were 
  thus 
  proved 
  to 
  be 
  leucite 
  and 
  not 
  

   a 
  new 
  form 
  of 
  KAlSi0 
  4 
  . 
  At 
  800° 
  with 
  potassium 
  tungstate 
  as 
  

   a 
  flux, 
  then, 
  KAlSi0 
  4 
  glass 
  is 
  largely 
  converted 
  to 
  leucite 
  crys- 
  

   tals 
  whereas 
  at 
  1300° 
  it 
  crystallizes 
  as 
  kaliophilite. 
  

  

  OrthorJiombic 
  form 
  of 
  RAlSiO 
  A 
  . 
  — 
  In 
  the 
  charges 
  heated 
  in 
  

   the 
  iridium 
  furnace 
  occasional 
  crystals 
  were 
  seen 
  with 
  polysyn- 
  

   thetic 
  twinning. 
  These 
  were 
  thought 
  to 
  be 
  kaliophilite 
  twinned 
  

   on 
  a 
  pyramidal 
  face 
  because 
  the 
  indices 
  were 
  sensibly 
  those 
  of 
  

   kaliophilite. 
  In 
  the 
  later 
  work 
  on 
  intermediate 
  mixtures 
  it 
  

   was 
  found 
  that 
  those 
  rich 
  in 
  kaliophilite 
  always 
  showed 
  this 
  

   twinned 
  form 
  when 
  quenched 
  from 
  high 
  temperatures. 
  These 
  

   better 
  crystals 
  were 
  found 
  to 
  be 
  biaxial. 
  The 
  crystals 
  are 
  

   usually 
  interpenetration 
  twins 
  giving 
  an 
  hexagonal 
  section 
  

  

  * 
  G. 
  W. 
  Morey, 
  Jour. 
  Am. 
  Chem. 
  Soc, 
  xxxvi, 
  217, 
  1914. 
  

  

  