﻿Posnjak 
  and 
  Merwin 
  — 
  Hydrated 
  Ferric 
  Oxides. 
  337 
  

  

  its 
  components, 
  i. 
  e., 
  ferric 
  oxide 
  and 
  water. 
  In 
  fig. 
  5 
  the 
  

   broken 
  line 
  connects 
  the 
  specific 
  volume 
  of 
  hematite 
  (spe- 
  

   cific 
  gravity 
  5-2) 
  and 
  water, 
  and 
  it 
  is 
  seen 
  that 
  this 
  line 
  

   greatly 
  deviates 
  from 
  the 
  points 
  experimentally 
  found. 
  

   The 
  solid 
  line 
  in 
  the 
  same 
  figure, 
  which 
  connects 
  the 
  

   specific 
  volumes 
  of 
  hematite 
  and 
  goethite, 
  however, 
  

   approaches 
  these 
  points 
  very 
  closely. 
  44 
  This 
  tends 
  to 
  

   indicate 
  that 
  turgite 
  is 
  essentially 
  a 
  solid 
  solution 
  of 
  fer- 
  

   ric 
  oxide 
  (hematite) 
  and 
  ferric 
  oxide 
  monohydrate 
  (goe- 
  

   thite). 
  All 
  other 
  evidence 
  at 
  hand 
  is 
  in 
  favor 
  of 
  this 
  

   assumption. 
  

  

  

  

  

  

  

  

  Fig. 
  

  

  5. 
  

  

  

  

  

  

  

  

  y 
  

  

  

  240 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y 
  

  

  y 
  

  

  

  

  

  .230 
  

  

  

  

  

  

  

  

  

  

  

  y 
  

  

  y 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y 
  

  

  

  

  

  

  

  

  .220 
  

  

  

  

  

  

  

  

  

  y 
  

  

  » 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  s 
  

  

  y 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y 
  

   y 
  

  

  

  

  

  

  

  

  

  

  

  

  

  200 
  

  

  

  

  y 
  

  

  y 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  y 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  190 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  % 
  Fe„0 
  o 
  .KP 
  

  

  100 
  

  

  2 
  

  

  =2^ 
  

  

  % 
  Fe 
  3 
  

  

  Fig. 
  5. 
  Specific 
  volumes 
  of 
  turgites. 
  The 
  solid 
  line 
  connects 
  the 
  specific 
  

   volumes 
  of 
  goethite 
  and 
  hematite, 
  while 
  the 
  broken 
  one 
  connects 
  those 
  of 
  

   hematite 
  and 
  water. 
  

  

  Some 
  Observations 
  Concerning 
  the 
  Relative 
  Stability 
  of 
  the 
  

   Hydrated 
  Ferric 
  Oxides. 
  

  

  The 
  questions 
  that 
  arise 
  as 
  a 
  result 
  of 
  the 
  present 
  

   investigation 
  concern 
  the 
  stability 
  relation 
  of 
  the 
  two 
  

   forms 
  of 
  ferric 
  oxide 
  monohydrate, 
  and 
  the 
  conditions 
  of 
  

   their 
  formation, 
  as 
  well 
  as 
  of 
  the 
  solid 
  solution. 
  While 
  

  

  44 
  The 
  specific 
  volume 
  of 
  No. 
  2 
  is 
  somewhat 
  higher 
  and 
  lies 
  closer 
  to 
  the 
  

   line 
  connecting 
  the 
  specific 
  volume 
  of 
  hematite 
  and 
  lepidocrocite. 
  In 
  view 
  

   of 
  the 
  small 
  number 
  of 
  turgite 
  specimens 
  at 
  our 
  disposal, 
  the 
  significance 
  of 
  

   this 
  could 
  not 
  be 
  ascertained, 
  but 
  it 
  is 
  evident 
  that 
  if, 
  besides 
  the 
  water 
  of 
  

   solid 
  solution 
  some 
  water 
  in 
  turgite 
  is 
  adsorbed, 
  its 
  specific 
  volume 
  would 
  

   have 
  a 
  higher 
  value. 
  However, 
  it 
  is 
  experimentally 
  impossible 
  at 
  present 
  

   to 
  determine 
  in 
  this 
  case 
  the 
  amount 
  of 
  adsorbed 
  water. 
  

  

  