﻿642 
  Palache 
  and 
  Graham 
  — 
  Crystallization 
  of 
  Willemite. 
  

  

  Of 
  the 
  forms 
  not 
  shown 
  in 
  the 
  drawings 
  the 
  second 
  order 
  

   rhombohedrons 
  u 
  and 
  s 
  occnr 
  rarely 
  as 
  minute 
  faces 
  modify- 
  

   ing 
  the 
  extreme 
  summit 
  of 
  the 
  crystals 
  ; 
  the 
  third 
  order 
  rhom- 
  

   bohedrons 
  j, 
  i, 
  and 
  I, 
  are 
  line 
  faces 
  truncating 
  the 
  edges 
  of 
  

   intersection 
  of 
  x, 
  y, 
  and 
  q 
  with 
  the 
  prisms. 
  The 
  form 
  a, 
  based 
  

   on 
  a 
  single 
  poor 
  reading, 
  is 
  doubtful. 
  

  

  Table 
  II 
  presents 
  a 
  summary 
  of 
  the 
  measurements 
  obtained 
  

   and 
  the 
  values 
  of 
  p 
  calculated 
  from 
  the 
  individual 
  forms. 
  In 
  

   this 
  table 
  the 
  complementary 
  forms 
  x 
  and 
  y, 
  d 
  and 
  D 
  are 
  

   united 
  for 
  the 
  sake 
  of 
  brevity 
  and 
  the 
  observed 
  angles 
  for 
  (j> 
  

   are 
  reduced 
  to 
  a 
  single 
  sectant. 
  The 
  calculated 
  angles 
  based 
  

   on 
  the 
  derived 
  value 
  of 
  p 
  are 
  also 
  included. 
  This 
  value 
  is 
  

   based 
  on 
  the 
  50 
  best 
  readings 
  from 
  faces 
  of 
  the 
  7 
  forms 
  placed 
  

   first 
  in 
  the 
  table. 
  The 
  value 
  of 
  p 
  is 
  *4453 
  corresponding 
  to 
  

   the 
  axial 
  ratio 
  a 
  : 
  c 
  = 
  1 
  : 
  '6679. 
  This 
  value 
  is 
  very 
  nearly 
  the 
  

   same 
  as 
  that 
  of 
  Levy 
  calculated 
  from 
  measurements 
  of 
  crystals 
  

   from 
  Moresnet 
  and 
  differs 
  quite 
  widely 
  from 
  the 
  one 
  to 
  which 
  

   reference 
  has 
  been 
  made, 
  proposed 
  by 
  Palache 
  and 
  based 
  on 
  

   poorer 
  crystals. 
  

  

  Levy-Moresnet 
  a:c= 
  1 
  : 
  -6696 
  

  

  Palache 
  and 
  Graham 
  F 
  : 
  F 
  :. 
  " 
  1 
  : 
  -6679 
  

   Palache 
  1910 
  " 
  " 
  1 
  : 
  '6612 
  

  

  p 
  o 
  = 
  -4464 
  

   p 
  o 
  = 
  -4453 
  

   p 
  = 
  '4408 
  

  

  Table 
  II. 
  

  

  •+3 
  

  

  'o 
  

   So 
  

  

  Measured 
  

  

  Limits 
  

  

  °.s 
  

  

  >> 
  

  

  Value 
  

   of 
  po 
  

  

  Calculated 
  

  

  <X> 
  

  

  

  

  

  

  

  £^ 
  

  

  

  calcu- 
  

  

  

  

  1-5 
  

  

  02 
  

  

  

  

  P 
  

  

  

  <P 
  

  

  

  P 
  

  

  

  OP 
  

  

  lated 
  

  

  t 
  

  

  P 
  

  

  r 
  

  

  +1 
  

  

  29°59' 
  

  

  37°41' 
  

  

  29°52 
  / 
  

  

  -30°06' 
  

  

  37°39' 
  

  

  -37°42' 
  

  

  8 
  

  

  Best 
  

  

  •4459 
  

  

  30°00' 
  

  

  37°39' 
  

  

  n 
  

  

  -2 
  

  

  30 
  00 
  

  

  57 
  03 
  

  

  29 
  57 
  

  

  -30 
  04 
  

  

  57 
  00 
  

  

  -57 
  06 
  

  

  5 
  

  

  • 
  << 
  

  

  •4451 
  

  

  a 
  

  

  57 
  03 
  

  

  k 
  

  

  *1 
  

  

  16 
  07 
  

  

  54 
  17 
  

  

  15 
  57 
  

  

  -16 
  17 
  

  

  54 
  14 
  

  

  -54 
  21 
  

  

  6 
  

  

  a 
  

  

  •4455 
  

  

  16 
  06 
  

  

  54 
  17 
  

  

  x 
  & 
  y 
  

  

  41 
  

  

  10 
  52 
  

  

  63 
  57 
  

  

  10 
  47 
  

  

  -10 
  58 
  

  

  63 
  52 
  

  

  -64 
  05 
  

  

  23 
  

  

  " 
  

  

  •4453 
  

  

  10 
  54 
  

  

  63 
  53 
  

  

  d&D 
  

  

  -84 
  

  

  10 
  54 
  

  

  45 
  36 
  

  

  10 
  50 
  

  

  -11 
  01 
  

  

  45 
  34 
  

  

  -45 
  41 
  

  

  9 
  

  

  a 
  

  

  •4446 
  

  

  10 
  54 
  

  

  45 
  34 
  

  

  o 
  

  

  21 
  

  

  19 
  14 
  

  

  49 
  30 
  

  

  19 
  04 
  

  

  -19 
  29 
  

  

  49 
  00 
  

  

  -49 
  47 
  

  

  5 
  

  

  poor 
  

  

  

  19 
  06 
  

  

  49 
  41 
  

  

  J 
  

  

  101 
  

  

  4 
  41 
  

  

  77 
  49 
  

  

  4 
  35 
  

  

  -4 
  52 
  

  

  77 
  46 
  

  

  -77 
  54 
  

  

  3 
  

  

  << 
  

  

  

  4 
  43 
  

  

  77 
  58 
  

  

  m) 
  

  

  101 
  

   —52 
  

  

  5 
  27 
  

   16 
  03 
  

  

  77 
  37 
  

   70 
  19 
  

  

  

  

  

  

  1 
  

   9 
  

  

  u 
  

   fair 
  

  

  .... 
  

  

  el 
  

  

  16 
  06 
  

  

  << 
  

   70 
  13 
  

  

  <i 
  

  

  15 
  47 
  

  

  -16 
  19 
  

  

  70 
  02 
  

  

  -70 
  38 
  

  

  i 
  

  

  -74 
  

  

  20 
  48 
  

  

  76 
  51 
  

  

  20 
  32 
  

  

  -21 
  00 
  76 
  45 
  

  

  -76 
  58 
  

  

  4 
  

  

  poor 
  

  

  

  

  21 
  03 
  

  

  76 
  54 
  

  

  In 
  addition 
  to 
  the 
  new 
  forms 
  determined 
  on 
  these 
  crystals 
  

   observations 
  had 
  previously 
  been 
  obtained 
  on 
  other 
  poorer 
  

   crystals 
  from 
  Franklin 
  Furnace 
  establishing 
  the 
  forms 
  n, 
  as, 
  

   and 
  ^ 
  and 
  two 
  additional 
  forms, 
  one 
  of 
  which 
  is 
  shown 
  in 
  Hg. 
  

   3. 
  These 
  measurements 
  follow 
  : 
  

  

  