﻿W. 
  P. 
  White 
  — 
  Silicate 
  Specific 
  Heats. 
  35 
  

  

  B 
  leaves 
  the 
  solution, 
  maintaining 
  the 
  chemical 
  equi- 
  

   librium, 
  and 
  all 
  the 
  material 
  will 
  crystallize 
  out 
  as 
  B 
  at 
  

   the 
  constant 
  temperature 
  of 
  WY. 
  If, 
  on 
  the 
  other 
  hand, 
  

   the 
  chemical 
  equilibrium 
  is 
  reached 
  slowly, 
  the 
  composi- 
  

   tion 
  will 
  not 
  follow 
  the 
  equilibrium 
  line 
  for 
  moderately 
  

   rapid 
  changes 
  of 
  temperature; 
  the 
  solubility 
  line 
  NP 
  

   will 
  be 
  cut 
  elsewhere 
  than 
  at 
  W, 
  as 
  at 
  W 
  1? 
  and 
  after 
  that 
  

   the 
  crystallization 
  will 
  also 
  alter 
  the 
  composition 
  of 
  the 
  

   liquid, 
  and 
  will 
  therefore 
  proceed 
  at 
  a 
  varying 
  tempera- 
  

   ture 
  from 
  the 
  varying 
  liquid. 
  

  

  The 
  " 
  theory 
  " 
  under 
  discussion 
  is 
  merely 
  the 
  corollary 
  

   of 
  the 
  assumptions 
  that 
  within 
  the 
  solid 
  crystals 
  of 
  

   inverting 
  substances 
  occur 
  chemical 
  changes 
  like 
  those 
  of 
  

   the 
  organic 
  liquids 
  of 
  fig. 
  3, 
  and 
  that 
  the 
  relation 
  between 
  

   two 
  inverting 
  solid 
  forms 
  is 
  governed 
  by 
  solubility 
  

   equilibria 
  like 
  those 
  between 
  the 
  solid 
  and 
  liquid 
  in 
  fig. 
  

   3. 
  B 
  (fig. 
  4, 
  heavy 
  lines) 
  now 
  crystallizes 
  out 
  of 
  the 
  crys- 
  

   tal 
  A 
  instead 
  of 
  out 
  of 
  a 
  liquid. 
  The 
  crystals, 
  however, 
  

   are 
  not 
  necessarily 
  supposed 
  to 
  be 
  pure 
  A 
  and 
  pure 
  B, 
  

   but, 
  as 
  appears 
  from 
  the 
  figure, 
  may 
  be 
  a, 
  or 
  A 
  containing 
  

   some 
  B, 
  and 
  /?, 
  or 
  B 
  containing 
  some 
  A. 
  Whether 
  they 
  

   are 
  always 
  so 
  appears 
  to 
  be 
  a 
  point 
  regarding 
  which 
  rival 
  

   forms 
  of 
  the 
  hypothesis 
  differ. 
  

  

  Fig. 
  4, 
  which 
  is 
  taken 
  from 
  Smits 
  with 
  a 
  change 
  of 
  

   lettering, 
  does 
  not 
  appear 
  to 
  give 
  a 
  logical 
  account 
  of 
  the 
  

   phenomena 
  when 
  the 
  chemical 
  equilibrium 
  is 
  not 
  fully 
  

   realized. 
  (Dotted 
  lines, 
  V, 
  W 
  x 
  , 
  X 
  1? 
  etc.) 
  For 
  in 
  that 
  

   case, 
  as 
  has 
  already 
  been 
  shown, 
  the 
  position 
  and 
  tem- 
  

   perature 
  of 
  Wj 
  should 
  not 
  remain 
  constant 
  as 
  the 
  change 
  

   proceeds, 
  and 
  do 
  not 
  remain 
  constant 
  in 
  the 
  metameric 
  

   mixed 
  liquids 
  to 
  which 
  the 
  solid 
  inversions 
  are 
  supposed 
  

   to 
  be 
  analogous. 
  

  

  This 
  hypothesis 
  is 
  really 
  rather 
  modest; 
  it 
  attempts 
  

   no 
  ultimate 
  explanations, 
  but 
  merely 
  a 
  simplification, 
  by 
  

   attributing 
  to 
  the 
  same 
  sort 
  of 
  machinery 
  the 
  observed 
  

   changes 
  in 
  some 
  liquids, 
  the 
  considerable 
  abrupt 
  changes 
  

   in 
  inverting 
  solids, 
  and 
  gradual 
  changes 
  which 
  may 
  occur 
  

   in 
  those 
  same 
  solids. 
  The 
  proof 
  of 
  the 
  validity 
  of 
  this 
  

   simplifying 
  view 
  seems 
  to 
  require 
  the 
  demonstration: 
  

   (1) 
  that 
  there 
  are 
  equilibrium 
  changes 
  in 
  the 
  solid 
  like 
  

   that 
  indicated 
  by 
  the 
  line 
  VW, 
  fig. 
  4; 
  (2) 
  that 
  these 
  are 
  

   connected 
  with 
  changes 
  in 
  the 
  inversion 
  temperature 
  such 
  

   as 
  are 
  indicated 
  by 
  the 
  line 
  NP 
  ; 
  and 
  (3) 
  that 
  the 
  change 
  

   indicated 
  bv 
  VW 
  is 
  chemicallv 
  the 
  same 
  as 
  one 
  concerned 
  

  

  