﻿Clarke 
  and 
  Steiger 
  — 
  Experiments 
  with 
  Pectolite^ 
  etc. 
  251 
  

  

  Analcite. 
  

  

  Analcite, 
  from 
  mauy 
  points 
  of 
  view, 
  is 
  a 
  species 
  of 
  peculiar 
  

   interest, 
  and 
  of 
  late 
  years 
  it 
  has 
  i^eceived 
  a 
  great 
  deal 
  of 
  atten- 
  

   tion. 
  Its 
  formula 
  may 
  be 
  written 
  in 
  various 
  ways, 
  especially 
  

   as 
  regards 
  the 
  interpretation 
  of 
  its 
  one 
  molecule 
  of 
  water 
  ; 
  but 
  

   evidence 
  too 
  often 
  has 
  yielded 
  before 
  pre-conceived 
  opinion. 
  

   Additional 
  evidence 
  is 
  now 
  available, 
  partly 
  from 
  the 
  experi- 
  

   ments 
  of 
  Friedel, 
  and 
  partly 
  from 
  the 
  data 
  obtained 
  during 
  the 
  

   present 
  investigation. 
  

  

  The 
  analcite 
  examined 
  by 
  us 
  was 
  in 
  well-developed 
  crystals 
  

   from 
  Wasson's 
  Bluff 
  in 
  E'ova 
  Scotia. 
  A 
  uniform 
  sample 
  was 
  

   prepared, 
  as 
  usual, 
  and 
  the 
  analysis, 
  given 
  below, 
  is 
  contrasted 
  

   with 
  the 
  theoretical 
  composition 
  required 
  by 
  the 
  accepted 
  em- 
  

   pirical 
  formula 
  ISTaAlSi^Oe 
  . 
  H^O. 
  

  

  

  

  Found. 
  

  

  Calculated. 
  

  

  Fractions 
  of 
  water. 
  

  

  SiO, 
  .. 
  

  

  

  . 
  57-06 
  

  

  54-55 
  

  

  At 
  100° 
  

  

  -. 
  -58 
  

  

  Al 
  O 
  . 
  

  

  

  . 
  21-48 
  

   •13 
  

  

  23-18 
  

  

  " 
  180° 
  

  

  " 
  260° 
  

  

  .. 
  1-16 
  

  

  Fe,0, 
  . 
  

  

  

  -. 
  3-64 
  

  

  CaO 
  .- 
  

  

  

  •16 
  

  

  

  '* 
  300° 
  .... 
  

  

  .. 
  1-57 
  

  

  Na,0 
  . 
  

  

  

  . 
  12-20 
  

  

  14-09 
  

  

  Low 
  redness. 
  

  

  .- 
  1-90 
  

  

  H,0 
  at 
  

  

  100° 
  

  

  •58 
  

  

  

  Full 
  redness 
  - 
  

  

  .. 
  -11 
  

  

  '- 
  over 
  100° 
  _.. 
  

  

  . 
  8-38 
  

  

  8-18 
  

  

  Blast 
  

  

  -_ 
  none 
  

  

  99-99 
  100-00 
  8-96 
  

  

  The 
  fractional 
  water 
  determinations 
  were 
  made 
  by 
  heating 
  in 
  

   an 
  air-bath 
  to 
  constant 
  weight 
  at 
  each 
  temperature 
  up 
  to 
  300°, 
  

   and 
  finally 
  over 
  the 
  direct 
  fiame. 
  The 
  first 
  fraction, 
  at 
  100°, 
  is 
  

   evidently 
  hygroscopic 
  or. 
  extraneous 
  water, 
  which 
  can 
  be 
  dis- 
  

   regarded. 
  The 
  remainder 
  of 
  the 
  water, 
  8*38 
  per 
  cent, 
  belongs 
  

   to 
  the 
  species. 
  The 
  significance 
  of 
  the 
  analytical 
  figures 
  will 
  

   be 
  considered 
  later. 
  

  

  Upon 
  boiling 
  the 
  powdered 
  analcite 
  with 
  sodium 
  carbonate 
  

   solution, 
  250 
  grams 
  to 
  the 
  liter 
  as 
  in 
  all 
  the 
  preceding 
  ex- 
  

   periments, 
  0-73 
  per 
  cent 
  of 
  silica 
  was 
  extracted. 
  After 
  igni- 
  

   tion 
  the 
  mineral 
  in 
  two 
  determinations 
  yielded 
  1*46 
  and 
  1*38 
  

   per 
  cent 
  respectively. 
  The 
  splitting 
  off 
  of 
  silica 
  is 
  therefore 
  

   very 
  slight 
  ; 
  and 
  one 
  of 
  the 
  formulae 
  proposed 
  by 
  Doelter,^ 
  

   J^a^Al^SijOg 
  -I- 
  21128103 
  may 
  be 
  set 
  aside 
  as 
  improbable. 
  Meta- 
  

   silicic 
  acid 
  or 
  an 
  acid 
  metasilicate 
  can 
  hardly 
  be 
  present 
  in 
  

   analcite 
  ; 
  although 
  the 
  possibility 
  of 
  a 
  neutral 
  metasilicate, 
  as 
  

   indicated 
  by 
  the 
  empirical 
  formula, 
  is 
  not 
  excluded. 
  By 
  

   Doelter's 
  formula 
  one-half 
  of 
  the 
  silica 
  ought 
  to 
  be 
  removable. 
  

  

  Upon 
  heating 
  analcite 
  with 
  dry 
  ammonium 
  chloride, 
  results 
  

   of 
  a 
  remarkable 
  character 
  were 
  obtained. 
  Sodium 
  chloride 
  

  

  