﻿Kuzirian 
  — 
  Water 
  of 
  Crystallization 
  in 
  Sulphates. 
  401 
  

  

  Art. 
  XXXYIII. 
  — 
  Determination 
  of 
  Water 
  of 
  Crystalliza- 
  

   tion 
  in 
  Sulphates 
  ; 
  by 
  S, 
  B. 
  Kuzirian. 
  

  

  [Contributions 
  from 
  the 
  Kent 
  Chemical 
  Laboratory 
  of 
  Yale 
  Univ. 
  — 
  ccl.] 
  

  

  Certain 
  substances, 
  e. 
  g. 
  chlorides 
  of 
  barium 
  and 
  calcium, 
  

   sulphates 
  of 
  sodium, 
  potassium, 
  barium, 
  etc., 
  are 
  completely 
  

   dehydrated 
  at 
  moderately 
  high 
  temperatures, 
  leaving 
  a 
  definite 
  

   and 
  weighable 
  compound. 
  Under 
  such 
  conditions, 
  when 
  the 
  

   substances 
  do 
  not 
  lose 
  anything 
  but 
  water, 
  at 
  a 
  definite 
  tem- 
  

   perature, 
  the 
  determination 
  of 
  water 
  of 
  crystallization 
  can 
  be 
  

   made 
  with 
  great 
  ease. 
  

  

  Certain 
  other 
  substances, 
  like 
  the 
  minerals, 
  talc, 
  topaz, 
  

   chondrodite, 
  staurolite, 
  do 
  not 
  lose 
  all 
  of 
  the 
  water 
  of 
  crystal- 
  

   lization 
  by 
  simple 
  ignition 
  at 
  moderate 
  temperatures. 
  The 
  

   high 
  heat 
  of 
  the 
  blast 
  lamp 
  is 
  in 
  such 
  cases 
  applied 
  for 
  the 
  

   complete 
  removal 
  of 
  water. 
  This 
  latter 
  step 
  often 
  gives 
  rise 
  

   to 
  complications, 
  when 
  the 
  material 
  to 
  be 
  blasted 
  changes 
  

   weight 
  otherwise 
  than 
  by 
  loss 
  of 
  water, 
  e. 
  g. 
  by 
  loss 
  of 
  carbon 
  

   dioxide, 
  fluorine, 
  chlorine, 
  or 
  by 
  accession 
  of 
  oxygen, 
  as 
  when 
  

   a 
  ferrous 
  compound 
  is 
  ignited 
  in 
  air. 
  

  

  Some 
  other 
  crystalline 
  substances 
  like 
  sulphates 
  and 
  alums 
  of 
  

   aluminum 
  and 
  chromium 
  are 
  decomposed 
  with 
  loss 
  of 
  material 
  

   other 
  than 
  water, 
  at 
  temperatures 
  obtainable 
  with 
  an 
  ordinary 
  

   good-sized 
  Bunsen 
  burner, 
  thus 
  preventing 
  a 
  correct 
  determin- 
  

   ation 
  of 
  their 
  crystalline 
  water. 
  

  

  Various 
  modifications 
  in 
  treatment 
  have 
  been 
  suggested 
  to 
  

   avoid 
  complication 
  in 
  water 
  determinations. 
  For 
  instance, 
  in 
  

   the 
  case 
  of 
  minerals, 
  talc, 
  topaz, 
  etc., 
  fusion 
  with 
  pure 
  and 
  dry 
  

   sodium 
  carbonate* 
  will 
  expel 
  the 
  water 
  which 
  may 
  be 
  absorbed 
  

   in 
  sulphuric 
  acid 
  and 
  weighed. 
  

  

  Fusion 
  of 
  such 
  silicates, 
  very 
  finely 
  pulverized, 
  with 
  an- 
  

   hydrous 
  powdered 
  borax, 
  is 
  another 
  method 
  suggested 
  by 
  

   Jannasch,f 
  for 
  the 
  same 
  object. 
  If 
  the 
  silicates 
  are 
  found 
  

   to 
  contain 
  fluorine, 
  then 
  a 
  retaining 
  layer 
  of 
  granular 
  lead 
  

   chromate 
  or 
  a 
  previously 
  fused 
  and 
  powdered 
  lead 
  oxide 
  is 
  

   used 
  in 
  the 
  ignition 
  tube. 
  This 
  process 
  is 
  found 
  objectionable 
  

   by 
  W. 
  H. 
  Hillebrand:}: 
  for 
  the 
  reason 
  that 
  silicates 
  on 
  fine 
  grind- 
  

   ing 
  lose 
  some 
  water. 
  

  

  Magnesia§ 
  is 
  another 
  substance 
  mentioned 
  in 
  connection 
  with 
  

   determination 
  of 
  crystalline 
  water 
  in 
  decomposable 
  compounds 
  

  

  * 
  Bulletin 
  422, 
  United 
  States 
  Geol. 
  Survey, 
  Hillebrand, 
  p. 
  79. 
  

  

  f 
  Praktischer 
  Leitfaden 
  der 
  Gewichtsanalyse, 
  Leipzig 
  (1897, 
  2d 
  ed.). 
  

  

  X 
  Bulletin 
  422, 
  United 
  States 
  Geol. 
  Survey, 
  Hillebrand, 
  p. 
  83. 
  

  

  § 
  F. 
  Stolba, 
  Zeitschr. 
  f. 
  analyt. 
  Chem, 
  vii, 
  23. 
  

  

  