﻿F. 
  T. 
  Long 
  — 
  Formation 
  of 
  Salt 
  Crystals. 
  289 
  

  

  Art. 
  XXIY. 
  — 
  The 
  Formation 
  of 
  Salt 
  Crystals 
  from 
  a 
  Hot 
  

   Saturated 
  Solution 
  / 
  by 
  E. 
  Tatum 
  Long. 
  

  

  In 
  1909 
  Professor 
  G. 
  D. 
  Harris 
  propounded 
  the 
  theory 
  that 
  

   the 
  " 
  Domes 
  " 
  of 
  Louisiana 
  and 
  Texas 
  are 
  due 
  to 
  the 
  force 
  

   exerted 
  by 
  growing 
  crystals 
  at 
  some 
  great 
  depth 
  where 
  a 
  

   saturated 
  hot 
  solution 
  from 
  below 
  became 
  cooled 
  and 
  thus 
  

   caused 
  a 
  precipitation 
  of 
  the 
  salt. 
  

  

  In 
  the 
  June 
  number 
  of 
  this 
  Journal 
  of 
  last 
  year 
  Mr. 
  

   Stephen 
  Taber 
  published 
  an 
  article 
  on 
  "The 
  Growth 
  of 
  Crystals 
  

   Under 
  External 
  Pressure." 
  While 
  the 
  latter' 
  s 
  experiments 
  

   were 
  in 
  progress 
  other 
  investigations 
  were 
  started 
  with 
  the 
  

   object 
  of 
  demonstrating 
  from 
  the 
  viewpoint 
  of 
  geology 
  and 
  

   physical-chemistry 
  that 
  a 
  saturated 
  hot 
  solution 
  of 
  sodium 
  

   chloride 
  when 
  cooled, 
  would 
  deposit 
  salt, 
  and 
  that 
  this 
  released 
  

   salt 
  would 
  form 
  crystals 
  which 
  in 
  growing 
  would 
  exert 
  an 
  ap- 
  

   preciable 
  force 
  and 
  which 
  would 
  continue 
  to 
  grow 
  in 
  spite 
  of 
  

   resistance. 
  

  

  Mr. 
  Taber's 
  object 
  was 
  " 
  determining 
  w 
  T 
  hether 
  it 
  is 
  possible 
  

   for 
  growing 
  crystals 
  to 
  exert 
  a 
  linear 
  pressure 
  and 
  if 
  so, 
  the 
  

   conditions 
  under 
  which 
  the 
  pressure 
  is 
  developed.' 
  1 
  Though 
  

   the 
  purpose 
  of 
  the 
  two 
  investigations 
  was 
  thus 
  somewhat 
  dif- 
  

   ferent, 
  one 
  fact 
  at 
  least 
  seems 
  to 
  have 
  been 
  demonstrated 
  in 
  

   common. 
  

  

  In 
  Mr. 
  Taber's 
  article, 
  "The 
  Growth 
  of 
  Crystals 
  Under 
  

   External 
  Pressure," 
  he 
  constantly 
  lays 
  stress 
  upon 
  the 
  necessity 
  

   that 
  the 
  surface 
  where 
  growth 
  is 
  to 
  take 
  place 
  be 
  in 
  contact 
  

   with 
  a 
  supersaturated 
  solution. 
  In 
  the 
  experiment 
  here 
  

   described, 
  another 
  salt 
  was 
  used 
  from 
  those 
  employed 
  by 
  Mr. 
  

   Taber, 
  but 
  the 
  same 
  fact 
  was 
  again 
  demonstrated. 
  The 
  crystals 
  

   ceased 
  to 
  grow 
  as 
  soon 
  as 
  the 
  supersaturated 
  solution 
  was 
  with- 
  

   drawn 
  from 
  their 
  surface. 
  Furthermore 
  the 
  rate 
  of 
  growth 
  

   was 
  largely 
  governed 
  by 
  the 
  amount 
  of 
  flow 
  and 
  hence 
  the 
  

   quantity 
  of 
  salt 
  released 
  for 
  crystallization. 
  

  

  An 
  apparatus 
  (fig. 
  1) 
  was 
  set 
  up 
  with 
  a 
  reservoir 
  A 
  placed 
  

   considerably 
  above 
  the 
  point 
  where 
  crystallization 
  was 
  to 
  take 
  

   place, 
  C. 
  This 
  reservoir 
  contained 
  cold 
  water 
  and 
  a 
  good 
  

   deal 
  more 
  common 
  table 
  salt 
  than 
  the 
  water 
  could 
  take 
  into 
  

   solution. 
  A 
  was 
  connected 
  with 
  B, 
  a 
  second 
  reservoir, 
  also 
  

   with 
  salt 
  in 
  excess, 
  by 
  a 
  long 
  glass 
  tube 
  with, 
  rubber 
  connec- 
  

   tions 
  to 
  short 
  glass 
  tubes, 
  placed 
  in 
  the 
  rubber 
  stoppers 
  in 
  the 
  

   side 
  necks 
  of 
  the 
  two 
  receivers. 
  On 
  the 
  lower 
  connection 
  a 
  

   stopcock 
  was 
  placed 
  so 
  as 
  to 
  regulate 
  the 
  flow 
  of 
  the 
  cold 
  brine 
  

   into 
  B. 
  A 
  Bunsen 
  burner 
  was 
  placed 
  under 
  B 
  and 
  a 
  thermom- 
  

   eter, 
  T, 
  was 
  run 
  through 
  the 
  top 
  stopper 
  well 
  down 
  into 
  the 
  

  

  