﻿Clarke 
  and 
  Steiger 
  — 
  Experiments 
  vnth 
  Pectolite^ 
  etc. 
  24T 
  

  

  boiling 
  the 
  powdered 
  pectolite 
  with 
  distilled 
  water 
  alone, 
  1*65 
  

   per 
  cent 
  of 
  silica 
  was 
  brought 
  into 
  solution, 
  and 
  the 
  ignited 
  

   mineral, 
  similarlj^ 
  treated 
  for 
  fifteen 
  minutes, 
  gave 
  l'T8 
  per 
  

   cent. 
  The 
  extraction 
  in 
  these 
  cases 
  is 
  really 
  an 
  extraction 
  of 
  

   alkaline 
  silicate 
  ; 
  as 
  the 
  two 
  following 
  experiments 
  prove. 
  In 
  

   A 
  the 
  unignited 
  pectolite 
  was 
  boiled 
  for 
  fourteen 
  hours 
  with 
  

   distilled 
  water 
  ; 
  and 
  in 
  B 
  the 
  mineral 
  after 
  ignition 
  was 
  sub- 
  

   jected 
  to 
  like 
  treatment 
  for 
  four 
  hours. 
  The 
  dissolved 
  matter 
  

   in 
  each 
  case 
  was 
  determined, 
  with 
  the 
  subjoined 
  results 
  : 
  

  

  Extracted. 
  A. 
  B. 
  

  

  SiO, 
  2-98 
  * 
  3-03 
  

  

  CaO 
  -30 
  -10 
  

  

  Na,0 
  -81 
  1-50 
  

  

  4-09 
  4-63 
  

  

  In 
  A, 
  no 
  simple 
  ratio 
  appears 
  ; 
  but 
  in 
  B 
  the 
  extracted 
  silicate 
  

   approximates 
  very 
  nearly 
  to 
  the 
  salt 
  Na^SijO^. 
  In 
  each 
  

   instance 
  the 
  ratios 
  vary 
  widely 
  from 
  those 
  of 
  the 
  original 
  min- 
  

   eral, 
  showing 
  that 
  actual 
  decomposition 
  and 
  not 
  a 
  solution 
  of 
  

   the 
  pectolite 
  as 
  such 
  has 
  occurred. 
  

  

  In 
  the 
  experiments 
  upon 
  pectolite 
  the 
  heating 
  with 
  dry 
  

   ammonium 
  chloride 
  was 
  omitted, 
  for 
  the 
  data 
  are 
  ah-eady 
  given 
  

   in 
  the 
  original 
  paper 
  by 
  Schneider 
  and 
  Clarke. 
  In 
  their 
  

   experiments 
  the 
  mineral 
  was 
  thrice 
  heated 
  with 
  ten 
  times 
  its 
  

   weight 
  of 
  the 
  reagent 
  to 
  above 
  350°, 
  and 
  then 
  leached 
  out 
  

   with 
  water. 
  In 
  the 
  solution 
  20*50 
  per 
  cent 
  of 
  lime 
  and 
  6*95 
  

   of 
  soda 
  were 
  found, 
  with 
  part 
  of 
  the 
  manganese 
  ; 
  showing 
  

   that 
  a 
  very 
  considerable 
  decomposition 
  had 
  taken 
  place. 
  Pos- 
  

   sibly, 
  by 
  repeated 
  treatments 
  with 
  ammonium 
  chloride 
  a 
  com- 
  

   plete 
  decomposition 
  might 
  be 
  effected 
  ; 
  but 
  this 
  question 
  is 
  

   one 
  upon 
  which 
  it 
  seemed 
  unnecessary 
  to 
  spend 
  further 
  time. 
  

  

  Pyropliyllite. 
  

  

  The 
  empirical 
  formula 
  for 
  pyrophyllite, 
  AlHSi^Og 
  is 
  appar- 
  

   ently 
  that 
  of 
  an 
  acid 
  metasilicate, 
  and 
  the 
  mineral 
  is 
  therefore 
  

   peculiarly 
  available 
  for 
  fractional 
  analysis. 
  The 
  compact 
  variety 
  

   from 
  Deep 
  River, 
  N. 
  C, 
  was 
  taken 
  for 
  examination, 
  and 
  a 
  

   uniform 
  sample 
  was 
  prepared. 
  Analysis 
  gave 
  the 
  following 
  

   results 
  : 
  

  

  SiO, 
  _..- 
  64-73 
  

  

  TiO, 
  -73 
  

  

  AIP3 
  29-16 
  

  

  Fe,03., 
  -49 
  

  

  MgO 
  -_ 
  „ 
  trace 
  

  

  Is^nition 
  o"35 
  

  

  100-46 
  

  

  