﻿R. 
  C. 
  Wells 
  — 
  New 
  Occurrence 
  of 
  Cuprodescloizite. 
  637 
  

  

  reduction 
  of 
  the 
  arsenate 
  in 
  a 
  closed 
  flask, 
  while 
  vanadium 
  

   remained 
  in 
  solution 
  in 
  the 
  quadrivalent 
  state. 
  After 
  boiling 
  

   out 
  all 
  hydrogen- 
  sulphide 
  and 
  heating 
  for 
  some 
  time, 
  sodium 
  

   carbonate 
  was 
  added 
  in 
  slight 
  excess, 
  thus 
  precipitating 
  chro- 
  

   mium 
  and 
  zinc. 
  The 
  latter 
  precipitate 
  was 
  ignited, 
  fused 
  

   with 
  sodium 
  carbonate, 
  and 
  the 
  melt 
  extracted 
  with 
  water. 
  

   Zinc 
  was 
  determined 
  in 
  the 
  insoluble 
  portion 
  by 
  separating 
  as 
  

   sulphide 
  and 
  weighing 
  as 
  sulphate. 
  Chromium 
  was 
  precip- 
  

   itated 
  in 
  the 
  water 
  portion 
  by 
  adding 
  a 
  slight 
  excess 
  of 
  nitric 
  

   acid 
  and 
  a 
  large 
  excess 
  of 
  lead 
  nitrate 
  and 
  the 
  lead 
  chromate 
  

   weighed 
  as 
  such 
  after 
  drying 
  at 
  110°. 
  Vanadium 
  was 
  deter- 
  

   mined 
  in 
  sulphuric 
  acid 
  solution 
  by 
  reduction 
  with 
  H 
  2 
  S 
  or 
  S0 
  2 
  

   and 
  titratiou 
  with 
  KMn0 
  4 
  , 
  the 
  small 
  amount 
  of 
  vanadium 
  

   carried 
  down 
  with 
  the 
  copper 
  being 
  separately 
  determined. 
  

   As 
  a 
  check 
  vanadium 
  was 
  also 
  determined 
  by 
  the 
  method 
  

   recommended 
  by 
  Cain 
  and 
  Hostetter,* 
  which 
  yielded 
  a 
  slightly 
  

   higher 
  result 
  than 
  by 
  the 
  first 
  method, 
  viz. 
  21/73 
  per 
  cent 
  

   instead 
  of 
  20*95. 
  No 
  other 
  elements 
  could 
  be 
  discovered 
  in 
  

   significant 
  amounts. 
  There 
  was 
  no 
  hygroscopic 
  water 
  at 
  

   105° 
  C. 
  In 
  order 
  to 
  see 
  if 
  the 
  mineral 
  had 
  lost 
  water 
  by 
  

   exposure 
  to 
  a 
  dry 
  atmosphere 
  it 
  was 
  kept 
  in 
  a 
  moist 
  atmos- 
  

   phere 
  for 
  two 
  weeks. 
  No 
  notable 
  absorption 
  of 
  water 
  

   occurred. 
  

  

  Analysis. 
  

  

  Molecular 
  

   12 
  3 
  Mean 
  values 
  

  

  Insol 
  

  

  •16 
  

  

  •18 
  

  

  

  

  •17 
  

  

  ... 
  

  

  PbO 
  

  

  ... 
  55*34 
  

  

  55-78 
  

  

  55-80 
  

  

  55-64 
  

  

  •251 
  

  

  CuO._._ 
  

  

  17-04 
  

  

  16-99 
  

  

  17-13 
  

  

  17-05 
  

  

  •214 
  

  

  ZnO 
  ._.. 
  

  

  -28 
  

  

  •34 
  

  

  

  

  •31 
  

  

  •004 
  

  

  v 
  a 
  o 
  5 
  ..... 
  

  

  ... 
  20-57 
  

  

  21-33 
  

  

  21-73 
  

  

  21-21 
  

  

  •116 
  

  

  As 
  2 
  5 
  ___. 
  

  

  ... 
  1-40 
  

  

  1-24 
  

  

  1-35 
  

  

  1-33 
  

  

  •006 
  

  

  PA— 
  - 
  

  

  -24 
  

  

  

  

  

  •24 
  

  

  •002 
  

  

  Cr0 
  3 
  ____ 
  

  

  .... 
  -57 
  

  

  •42 
  

  

  

  

  •50 
  

  

  •005 
  

  

  H 
  a 
  O 
  .... 
  

  

  3-63 
  

  

  3-51 
  

  

  

  

  3-57 
  

  

  •198 
  

  

  124 
  

  

  100-02 
  

  

  Discussion 
  of 
  Analysis. 
  — 
  On 
  comparing 
  the 
  analysis 
  with 
  

   those 
  of 
  well-recognized 
  species, 
  the 
  mineral 
  is 
  found 
  to 
  be 
  

   best 
  described 
  by 
  the 
  name 
  cuprodescloizite. 
  Two 
  interesting 
  

   facts 
  appear. 
  The 
  percentage 
  of 
  copper 
  is 
  higher 
  than 
  in 
  any 
  

   variety 
  of 
  cuprodescloizite 
  hitherto 
  reported 
  and 
  there 
  is 
  a 
  

   small 
  amount 
  of 
  chromium. 
  Although 
  the 
  proportion 
  of 
  

   copper 
  suggests 
  psittacinite, 
  it 
  seems 
  probable, 
  in 
  view 
  of 
  the 
  

   variable 
  amounts 
  of 
  lead 
  and 
  water 
  reported 
  in 
  psittacinite, 
  

   that 
  the 
  latter 
  mineral 
  is 
  an 
  alteration 
  product 
  of 
  descloizite. 
  

   The 
  present 
  mineral, 
  it 
  is 
  true, 
  has 
  an 
  excess 
  of 
  water 
  over 
  the 
  

  

  * 
  J. 
  R. 
  Cain 
  and 
  J. 
  C. 
  Hostetter 
  : 
  A 
  rapid 
  method 
  for 
  the 
  determination 
  

   of 
  vanadium 
  in 
  steels, 
  ores, 
  etc. 
  J. 
  Ind. 
  and 
  Eng. 
  Chem., 
  iv, 
  250, 
  1912. 
  

  

  