﻿182 
  Foote 
  and 
  Bradley 
  — 
  Solid 
  Solution 
  in 
  Minerals. 
  

  

  washing 
  with 
  solvents. 
  After 
  such 
  treatment, 
  when 
  heated 
  

   in 
  a 
  closed 
  tube, 
  the 
  mineral 
  gave 
  off 
  not 
  only 
  its 
  water, 
  but 
  

   also 
  an 
  oily 
  liquid, 
  presumably 
  the 
  tetrabromide 
  or 
  a 
  decom- 
  

   position 
  product. 
  We 
  were 
  therefore 
  forced 
  to 
  abandon 
  this 
  

   method 
  of 
  purification. 
  The 
  fact 
  that 
  the 
  tetrabromide 
  is 
  

   absorbed 
  is 
  interesting, 
  however, 
  as 
  it 
  suggests 
  a 
  comparison 
  

   with 
  some 
  of 
  the 
  hydrogels 
  like 
  silicic 
  acid, 
  which 
  also 
  absorb 
  

   various 
  organic 
  liquids. 
  Our 
  only 
  means 
  of 
  purification, 
  there- 
  

   fore, 
  was 
  by 
  most 
  careful 
  picking. 
  Small 
  lumps 
  of 
  material 
  

   which 
  appeared 
  pure, 
  or 
  nearly 
  so, 
  were 
  broken 
  up, 
  sifted 
  to 
  

   uniform 
  size, 
  and 
  separated 
  under 
  a 
  magnifying 
  glass. 
  The 
  

   material 
  was 
  afterward 
  examined 
  more 
  carefully 
  under 
  a 
  higher 
  

   power 
  microscope. 
  Nos. 
  1 
  and 
  3 
  were 
  almost 
  perfectly 
  pure 
  

   and 
  uniform 
  in 
  appearance. 
  No. 
  2 
  was 
  very 
  slightly 
  mottled 
  

   in 
  color. 
  The 
  method 
  of 
  analysis 
  was 
  as 
  follows 
  : 
  The 
  mineral 
  

   was 
  decomposed 
  with 
  hydrochloric 
  acid 
  and 
  silica 
  separated 
  

   by 
  two 
  evaporations, 
  as 
  usual. 
  It 
  was 
  tested 
  for 
  impurities 
  

   by 
  evaporation 
  with 
  hydrofluoric 
  acid. 
  In 
  the 
  filtrate 
  from 
  

   silica, 
  copper 
  was 
  precipitated 
  as 
  sulphide 
  and 
  weighed 
  as 
  Cu 
  2 
  S. 
  

   The 
  other 
  bases 
  were 
  determined 
  in 
  the 
  filtrate 
  in 
  the 
  usual 
  

   manner 
  after 
  removing 
  hydrogen 
  sulphide. 
  Water 
  was 
  deter- 
  

   mined 
  directly 
  by 
  Penfield's 
  method.* 
  

  

  The 
  results 
  obtained 
  are 
  given 
  in 
  Table 
  II. 
  

  

  Table 
  II. 
  

  

  New 
  Analyses 
  of 
  Chrysocolla 
  (by 
  Bradley). 
  

  

  I 
  . 
  II 
  

  

  Locality, 
  Arizona 
  Locality, 
  Montana 
  

  

  1 
  2 
  Average 
  1 
  2 
  Average 
  

  

  SiO 
  s 
  38-16 
  38-12 
  38*14 
  50-32 
  50-57 
  50*45 
  

  

  CuO 
  36-71 
  36-77 
  36*74 
  37*77 
  38-12 
  37'94 
  

  

  H 
  2 
  18*67 
  18*79 
  18*73 
  11*22 
  11*00 
  11*11 
  

  

  A1 
  2 
  3 
  5-56 
  5-75 
  5*66 
  

  

  CaO 
  -89 
  -91 
  -90 
  _.- 
  

  

  99-99 
  100-34 
  100-17 
  

  

  III 
  

   Locality, 
  Arizona 
  

  

  1 
  2 
  

  

  SiO, 
  38-31 
  38*32 
  

  

  CuO 
  39*98 
  39-97 
  

  

  H 
  2 
  19*88 
  19*86 
  

  

  A1 
  2 
  3 
  *91 
  1*04 
  

  

  CaO 
  *72 
  -84 
  

  

  •31 
  99*69 
  99-50 
  

  

  Average 
  

   38*32 
  

   39*98 
  

   19*87 
  

  

  •98 
  

  

  •78 
  

  

  99*80 
  100*03 
  99*92 
  

   * 
  This 
  Journal, 
  lxviii, 
  30, 
  1894. 
  

  

  