﻿Pratt 
  and 
  Foote 
  — 
  Wellsite, 
  a 
  new 
  Mineral. 
  447 
  

  

  weight 
  became 
  constant. 
  The 
  last 
  trace 
  of 
  water 
  could 
  only 
  

   be 
  driven 
  off 
  by 
  heating 
  the 
  mineral 
  over 
  the 
  blast 
  lamp. 
  

  

  Loss. 
  

  

  At 
  100° 
  C 
  nothing. 
  

  

  125 
  1-93) 
  

  

  175 
  1-48 
  5-4 
  

  

  200 
  0-92 
  

  

  260 
  - 
  

  

  KS}« 
  

  

  295 
  "- 
  69 
  

  

  Red 
  heat 
  4*96 
  ) 
  

  

  Over 
  blast 
  lamp 
  0*33 
  [ 
  

  

  Total 
  13-31 
  

  

  As 
  is 
  seen 
  from 
  the 
  above, 
  about 
  one-third 
  of 
  the 
  water, 
  or 
  

   one 
  molecule, 
  is 
  given 
  off 
  between 
  100° 
  and 
  200°, 
  another 
  

   third 
  approximately 
  between 
  200° 
  and 
  300°, 
  while 
  the 
  remain- 
  

   der 
  is 
  expelled 
  only 
  at 
  an 
  intense 
  heat. 
  This 
  would 
  indicate 
  

   that 
  the 
  water 
  exists 
  in 
  three 
  different 
  conditions 
  in 
  the 
  mole- 
  

   cule. 
  If 
  only 
  that 
  which 
  is 
  expelled 
  below 
  200° 
  be 
  regarded 
  

   as 
  water 
  of 
  crystallization, 
  the 
  composition 
  would 
  be 
  H 
  4 
  R 
  // 
  A1 
  8 
  

   Si 
  3 
  12 
  +H 
  2 
  0. 
  

  

  That 
  the 
  new 
  mineral 
  would 
  be 
  closely 
  related 
  to 
  the 
  phil- 
  

   lipsite 
  group 
  of 
  the 
  zeolites, 
  was 
  expected 
  from 
  the 
  first 
  on 
  

   account 
  of 
  its 
  crystalline 
  form, 
  and 
  this 
  relation 
  is 
  very 
  satis- 
  

   factorily 
  brought 
  out 
  by 
  a 
  comparison 
  of 
  the 
  crystallographic 
  

   properties 
  and 
  chemical 
  composition. 
  

  

  They 
  all 
  have 
  very 
  nearly 
  the 
  same 
  axial 
  ratios 
  : 
  

  

  d 
  : 
  b 
  : 
  6 
  

  

  Wellsite 
  '768 
  : 
  1 
  : 
  1-245 
  j3 
  — 
  53° 
  27' 
  

  

  Philfipsite 
  -70949:1:1-2563 
  £ 
  = 
  55 
  37 
  

  

  Harmotome-. 
  -70315 
  : 
  1 
  : 
  1*2310 
  j3 
  = 
  55 
  10 
  

  

  Stilbite 
  -76227:1:1-19401 
  £=50 
  49f 
  

  

  In 
  their 
  habit 
  and 
  method 
  of 
  twinning, 
  they 
  are 
  also' 
  very 
  

   similar, 
  all 
  the 
  crystals 
  being 
  uniformly 
  penetration 
  twins. 
  

   This 
  is 
  especially 
  noticeable 
  between 
  the 
  new 
  mineral 
  and 
  

   phillipsite 
  and 
  harmotome 
  which 
  are 
  common 
  as 
  double 
  twins 
  

   with 
  c, 
  001 
  and 
  e, 
  011 
  as 
  twinning 
  planes. 
  

  

  The 
  place 
  of 
  the 
  mineral 
  in 
  the 
  phillipsite 
  group 
  is 
  clearly 
  

   shown 
  by 
  a 
  comparison 
  of 
  their 
  chemical 
  compositions. 
  

   Arranged 
  in 
  order 
  of 
  their 
  proportions 
  of 
  silica 
  and 
  water 
  to 
  

   the 
  bases, 
  we 
  have 
  the 
  following 
  interesting 
  series, 
  in 
  which 
  R 
  

   represents 
  the 
  bivalent 
  elements 
  : 
  

  

  Wellsite 
  RAl 
  2 
  Si 
  3 
  O 
  10 
  .3H„O 
  

  

  Phillipsite 
  ........ 
  RAl 
  2 
  Si 
  4 
  12 
  . 
  4|H„0 
  

  

  Harmotome 
  RAl 
  2 
  Si 
  5 
  14 
  . 
  5H 
  2 
  

  

  Stilbite 
  RA] 
  2 
  Si 
  6 
  16 
  .6lI 
  2 
  

  

  The 
  ratio 
  of 
  RO 
  : 
  A1 
  2 
  3 
  is 
  constant, 
  1 
  : 
  1, 
  in 
  the 
  series, 
  while 
  

  

  