﻿Clarke 
  and 
  Steiger 
  — 
  Experiments 
  with 
  Pectolite^ 
  etc. 
  255 
  

  

  But 
  whatever 
  its 
  mode 
  of 
  union 
  may 
  be, 
  the 
  amount 
  of 
  water 
  

   corresponds 
  to 
  the 
  simple 
  molecular 
  ratio 
  which 
  is 
  indicated 
  

   in 
  the 
  formula 
  of 
  the 
  species. 
  One 
  molecule 
  of 
  analcite 
  holds 
  

   a 
  certain 
  definite 
  number 
  of 
  water 
  molecules 
  ; 
  and 
  FriedePs 
  

   observations 
  are 
  not 
  incompatible 
  with 
  the 
  idea 
  that 
  these 
  are 
  

   retained 
  with 
  varying 
  degrees 
  of 
  tenacity. 
  This 
  idea 
  is 
  sug- 
  

   gested 
  by 
  the 
  various 
  series 
  of 
  fractionation 
  experiments 
  which 
  

   have 
  been 
  made 
  from 
  time 
  to 
  time, 
  by 
  independent 
  workers, 
  

   even 
  though 
  the 
  data 
  are 
  not 
  by 
  any 
  means 
  concordant. 
  Thus 
  

   Lepierre^ 
  found 
  that 
  half 
  the 
  water 
  of 
  analcite 
  was 
  driven 
  off 
  

   at 
  or 
  below 
  300°, 
  the 
  other 
  half 
  above 
  440°. 
  In 
  our 
  own 
  

   experiments 
  three-fourths 
  were 
  expelled 
  at 
  300°, 
  the 
  remain- 
  

   ing 
  fourth 
  being 
  held 
  up 
  to 
  a 
  much 
  higher, 
  but 
  undetermined 
  

   temperature. 
  In 
  both 
  series 
  the 
  water 
  fractions 
  are 
  repre- 
  

   sentable 
  by 
  fourths 
  ; 
  but 
  Friedel's 
  experimentsf 
  indicate 
  a 
  con- 
  

   tinuity 
  of 
  loss 
  in 
  weight 
  of 
  quite 
  a 
  dissimilar 
  order. 
  Friedel 
  

   holds 
  that 
  all 
  of 
  the 
  water 
  fractionations 
  heretofore 
  made 
  upon 
  

   analcite 
  are 
  fallacious, 
  and 
  that 
  no 
  definite 
  fractions 
  can 
  be 
  

   identified, 
  a 
  conclusion 
  strongly 
  supported 
  by 
  his 
  own 
  data, 
  

   even 
  though 
  the 
  proof 
  is 
  not 
  absolutely 
  positive. 
  The 
  most 
  

   that 
  can 
  be 
  said 
  is, 
  that 
  the 
  weight 
  of 
  evidence, 
  so 
  far, 
  is 
  in 
  

   favor 
  of 
  FriedePs 
  contention, 
  but 
  that 
  additional 
  investigation 
  

   is 
  necessary 
  in 
  order 
  to 
  reconcile 
  all 
  discrepancies. 
  The 
  full 
  

   significance 
  of 
  the 
  water 
  in 
  analcite 
  remains 
  unknown. 
  

  

  In 
  order 
  to 
  discuss 
  the 
  constitution 
  of 
  analcite, 
  let 
  us 
  recur 
  

   to 
  the 
  analysis 
  of 
  the 
  mineral 
  itself. 
  It 
  is 
  at 
  once 
  evident 
  from 
  

   the 
  comparison 
  made 
  on 
  a 
  preceding 
  page 
  that 
  our 
  sample 
  of 
  

   the 
  mineral 
  varies 
  notably 
  in 
  composition 
  from 
  the 
  require- 
  

   ments 
  of 
  theory. 
  The 
  silica 
  is 
  two 
  and 
  one-half 
  per 
  cent 
  too 
  

   high, 
  while 
  alumina 
  and 
  soda 
  are 
  correspondingly 
  low. 
  ITo 
  

   probable 
  impurity 
  and 
  no 
  presumable 
  errors 
  of 
  manipulation 
  

   can 
  amount 
  for 
  so 
  great 
  a 
  divergence. 
  If 
  we 
  consult 
  other 
  

   analyses, 
  as 
  we 
  find 
  them 
  tabulated 
  in 
  manuals 
  like 
  those 
  of 
  

   Dana 
  and 
  of 
  Hintze, 
  we 
  shall 
  find 
  other 
  cases 
  resembling 
  this, 
  

   and 
  also 
  examples 
  of 
  variation 
  in 
  the 
  opposite 
  direction, 
  with 
  

   silica 
  low 
  and 
  an 
  apparent 
  excess 
  of 
  bases. 
  Most 
  analcite 
  gives 
  

   quite 
  sharply 
  the 
  metasilicate 
  ratios 
  required 
  by 
  the 
  accepted 
  

   formula 
  ; 
  but 
  the 
  variations 
  from 
  it 
  are 
  large 
  enough, 
  com- 
  

   mon 
  enough 
  and 
  regular 
  enough 
  to 
  command 
  attention. 
  The 
  

   analyses 
  are 
  not 
  all 
  covered 
  by 
  the 
  recognized 
  theory 
  ; 
  and 
  the 
  

   apparent 
  irregularities 
  are 
  not 
  fortuitous, 
  but 
  are 
  systematic 
  in 
  

   character. 
  

  

  One 
  explanation 
  of 
  the 
  seeming 
  anomalies 
  is 
  simple 
  and 
  

   clear. 
  If 
  analcite, 
  instead 
  of 
  being 
  a 
  metasilicate, 
  is 
  really 
  a 
  

  

  * 
  Bull. 
  Soc. 
  Chim. 
  (3), 
  xv, 
  561, 
  1896. 
  

   t 
  Bull. 
  Soc. 
  Min., 
  xix, 
  363, 
  1896. 
  

  

  Am. 
  Jour. 
  Scr. 
  — 
  Fourth 
  Series, 
  Vol. 
  Ytll, 
  No. 
  46. 
  — 
  October, 
  1899. 
  

   18 
  

  

  