﻿Penfield 
  and 
  Wa?'7'e?i 
  — 
  Composition 
  of 
  Parisite, 
  23 
  

  

  oxides. 
  The 
  amount 
  of 
  cerium 
  oxide, 
  Ce^Oa, 
  was 
  estimated 
  by 
  

   decomposing 
  the 
  ignited 
  oxides 
  (CeO^, 
  La^Og 
  and 
  DijOg) 
  with 
  

   sulphuric 
  acid, 
  to 
  which 
  some 
  oxalic 
  acid 
  was 
  added, 
  and 
  weigh- 
  

   ing 
  the 
  carbon 
  dioxide 
  liberated 
  by 
  the 
  higher 
  oxide 
  of 
  cerium, 
  

   according 
  to 
  the 
  equation, 
  2CeO, 
  + 
  H,C,0,= 
  Ce,03 
  + 
  2CO,+ 
  

   H2O. 
  The 
  joint 
  molecular 
  weight 
  of 
  the 
  cerium, 
  lanthanum, 
  

   and 
  didymium 
  oxides 
  (Ce, 
  La, 
  Di^-^Og 
  was 
  estimated 
  by 
  con- 
  

   verting 
  a 
  weighed 
  quantity 
  of 
  the 
  oxides 
  into 
  sulphates 
  and 
  was 
  

   found 
  to 
  be 
  328-2. 
  The 
  results 
  of 
  the 
  analyses 
  are 
  given 
  beyond. 
  

   As 
  the 
  considerable 
  amount 
  of 
  impurities 
  in 
  the 
  Montana 
  

   parisite 
  rendered 
  the 
  calculation 
  of 
  the 
  formula 
  somewhat 
  

   uncertain, 
  an 
  analysis 
  of 
  the 
  mineral 
  from 
  Muso 
  Valley 
  was 
  

   also 
  made. 
  Exceptionally 
  pure 
  material 
  for 
  this 
  analysis 
  was 
  

   obtained 
  from 
  a 
  frao^ment 
  of 
  a 
  lars^e 
  crvstal 
  in 
  the 
  Brush 
  coUec- 
  

   tion. 
  In 
  this 
  analysis 
  it 
  was 
  found 
  that 
  the 
  full 
  amount 
  of 
  

   fluorine 
  was 
  not 
  obtained 
  by 
  a 
  single 
  fusion 
  with 
  sodium 
  car- 
  

   bonate 
  and 
  silica, 
  and 
  soaking 
  out 
  with 
  water. 
  By 
  saving 
  the 
  

   residues 
  and 
  fusing 
  them 
  a 
  second 
  time 
  with 
  sodium 
  carbonate 
  

   and 
  a 
  slight 
  addition 
  of 
  silica, 
  about 
  0*5 
  per 
  cent 
  of 
  fluorine 
  was 
  

   obtained. 
  This 
  precaution 
  was 
  not 
  taken 
  in 
  the 
  analysis 
  of 
  the 
  

   Montana 
  mineral 
  and 
  consequently 
  the 
  ratio 
  of 
  the 
  fluorine 
  in 
  

   that 
  analysis 
  is 
  a 
  little 
  low. 
  The 
  joint 
  molecalar 
  weight 
  of 
  

   the 
  cerium, 
  lanthanum 
  and 
  didymium 
  oxides 
  was 
  found 
  to 
  be 
  

   3284. 
  The 
  results 
  of 
  the 
  analyses 
  are 
  given 
  below, 
  together 
  

   with 
  the 
  analysis 
  by 
  Damour 
  and 
  Deville^ 
  of 
  the 
  parisite 
  

   from 
  Muso. 
  

  

  T. 
  11. 
  III. 
  

  

  Warren. 
  Warren. 
  Damour 
  and 
  Deville. 
  

  

  Montana. 
  Ratio. 
  Muso. 
  Ratio. 
  Muso. 
  Ratio. 
  

  

  Specific 
  gravity, 
  4-128 
  4'302 
  4-358 
  

  

  C0„ 
  22-98 
  -521 
  24-22 
  'ooO 
  23-48 
  -533 
  

  

  F_^ 
  5-90 
  -310 
  6-82 
  '359 
  5-55 
  '292 
  

  

  CeA 
  26-14^ 
  30-67) 
  44-21) 
  

  

  (La, 
  Di).03 
  .... 
  28-46^ 
  ^^^ 
  29-74^ 
  ^^'^ 
  18-00 
  j" 
  ^^^ 
  

  

  CaO 
  10-98 
  -196 
  10-70 
  -191 
  10-10 
  -180 
  

  

  Fe^g 
  (pyrite?). 
  -80 
  -20 
  101-34 
  

  

  Na^O 
  . 
  -69 
  -20 
  0= 
  2F 
  = 
  2-34 
  

  

  K^O 
  -19 
  .10 
  99-00 
  

  

  H,0 
  -26 
  102-65 
  

  

  Gangiaebyj 
  o 
  = 
  2F=2-87 
  

  

  dmerence. 
  \ 
  

  

  102-48 
  99-78 
  

  

  = 
  2F 
  2-48 
  

  

  10000 
  

  

  *C. 
  R., 
  lix, 
  p. 
  270, 
  186J. 
  

  

  