﻿Foote 
  and 
  Bradley 
  — 
  Solid 
  Solution 
  in 
  Minerals. 
  181 
  

  

  

  

  

  Table 
  I. 
  

  

  

  

  

  

  Eatios 
  calculated 
  from 
  

  

  Analyses 
  of 
  Chrysocolla. 
  

  

  

  Dana 
  

  

  

  

  

  Hintze 
  

  

  

  

  

  No. 
  

  

  Si0 
  2 
  

  

  CuO 
  

  

  H 
  2 
  

  

  No. 
  

  

  Si0 
  2 
  

  

  CuO 
  

  

  H 
  2 
  

  

  1 
  

  

  1-20 
  

  

  1-00 
  

  

  2-23 
  

  

  4 
  

  

  2-60 
  

  

  1-00 
  

  

  3'40 
  

  

  9 
  

  

  1-05 
  

  

  a 
  

  

  1-86 
  

  

  5 
  

  

  •81 
  

  

  a 
  

  

  2-48 
  

  

  3 
  

  

  1-33 
  

  

  a 
  

  

  3-59 
  

  

  6 
  

  

  1-07 
  

  

  u 
  

  

  2-09 
  

  

  4 
  

  

  1-08 
  

  

  a 
  

  

  1-66 
  

  

  8 
  

  

  1-15 
  

  

  a 
  

  

  2-32 
  

  

  5 
  

  

  1-06 
  

  

  a 
  

  

  2'58 
  

  

  9 
  

  

  I'll 
  

  

  tt 
  

  

  3-70 
  

  

  6 
  

  

  •71 
  

  

  a 
  

  

  1-47 
  

  

  10 
  

  

  1-03 
  

  

  a 
  

  

  2-95 
  

  

  

  2-68 
  

  

  tt 
  

  

  5-06 
  

  

  11 
  

  

  1-01 
  

  

  a 
  

  

  2-16 
  

  

  8 
  

  

  1-35 
  

  

  tt 
  

  

  4-21 
  

  

  14 
  

  

  1-23 
  

  

  a 
  

  

  1-65 
  

  

  9 
  

  

  1-89 
  

  

  a 
  

  

  4-40 
  

  

  22 
  

  

  1-88 
  

  

  a 
  

  

  3-91 
  

  

  10 
  

  

  2-13 
  

  

  a 
  

  

  2-62 
  

  

  23 
  

  

  •94 
  

  

  a 
  

  

  2-74 
  

  

  11 
  

  

  1-60 
  

  

  a 
  

  

  2-67 
  

  

  24 
  

  

  2*33 
  

  

  tt 
  

  

  2'50 
  

  

  12 
  

  

  3-54 
  

  

  a 
  

  

  1-03 
  

  

  25 
  

  

  •39 
  

  

  a 
  

  

  1-23 
  

  

  13 
  

  

  1-62 
  

  

  a 
  

  

  •96 
  

  

  26 
  

  

  •18 
  

  

  a 
  

  

  •70 
  

  

  14 
  

  

  •97 
  

  

  tt 
  

  

  2-24 
  

  

  

  

  

  

  15 
  

  

  •33 
  

  

  tt 
  

  

  •49 
  

  

  

  

  

  

  16 
  

  

  •88 
  

  

  a 
  

  

  2-66 
  

  

  

  

  

  

  17 
  

  

  1-07 
  

  

  it 
  

  

  3-63 
  

  

  

  

  

  

  18 
  

  

  1-37 
  

  

  tt 
  

  

  4-19 
  

  

  

  

  

  

  are 
  above 
  2*20. 
  To 
  put 
  the 
  results 
  in 
  another 
  way, 
  only 
  12 
  

   out 
  of 
  62 
  ratios, 
  or 
  less 
  than 
  20 
  per 
  cent, 
  are 
  reasonably 
  close 
  

   to 
  the 
  theory 
  for 
  chrysocolla. 
  So 
  far, 
  then, 
  as 
  the 
  evidence 
  

   goes 
  which 
  can 
  be 
  derived 
  from 
  the 
  analyses 
  given, 
  there 
  is 
  

   little 
  to 
  support 
  the 
  formula 
  CuSi0 
  3 
  .2H 
  2 
  0. 
  On 
  the 
  other 
  

   hand, 
  there 
  is 
  just 
  as 
  little 
  evidence 
  in 
  support 
  of 
  any 
  other 
  

   single 
  formula. 
  

  

  To 
  obtain 
  further 
  evidence, 
  we 
  have 
  analyzed 
  three 
  speci- 
  

   mens 
  of 
  chrysocolla. 
  The 
  main 
  difficulty 
  in 
  determining 
  the 
  

   composition 
  of 
  chrysocolla 
  is 
  in 
  obtaining 
  pure 
  material. 
  By 
  

   this 
  we 
  mean 
  material 
  which 
  is 
  homogeneous. 
  For 
  if 
  different 
  

   specimens 
  of 
  chrysocolla 
  are 
  each 
  homogeneous 
  and 
  not 
  mechan- 
  

   ical 
  mixtures, 
  and 
  show 
  the 
  essential 
  characteristics 
  of 
  the 
  min- 
  

   eral, 
  we 
  can 
  see 
  no 
  reason 
  why 
  they 
  must 
  not 
  all 
  be 
  regarded 
  

   as 
  this 
  mineral 
  even 
  if 
  the 
  composition 
  varies 
  in 
  the 
  different 
  

   specimens 
  in 
  a 
  manner 
  which 
  is 
  not 
  of 
  the 
  character 
  of 
  ordi- 
  

   nary 
  isomorphous 
  replacement. 
  The 
  samples 
  of 
  chrysocolla 
  

   chosen 
  for 
  our 
  work 
  were 
  picked 
  from 
  exceptionally 
  fine 
  large 
  

   specimens. 
  We 
  were 
  unable, 
  however, 
  to 
  use 
  heavy 
  solutions 
  

   for 
  final 
  purification. 
  Potassium 
  mercuric 
  iodide 
  solution, 
  

   which 
  was 
  first 
  tried, 
  reacted 
  with 
  the 
  mineral. 
  Acetylene 
  

   tetrabromide 
  could 
  apparently 
  be 
  used 
  and 
  a 
  sample 
  of 
  the 
  

   mineral 
  was 
  obtained 
  by 
  its 
  means 
  of 
  specific 
  gravity 
  2*336. 
  

   We 
  soon 
  found, 
  however, 
  that 
  this 
  material 
  had 
  absorbed 
  the 
  

   tetrabromide 
  in 
  such 
  a 
  manner 
  that 
  it 
  could 
  not 
  be 
  removed 
  by 
  

  

  