﻿Kuzirian 
  — 
  Water 
  of 
  Crystallization 
  in 
  Sulphates. 
  403 
  

  

  sulphate 
  (CnS0 
  4 
  *5H 
  a 
  O) 
  — 
  was 
  mixed 
  well 
  with 
  the 
  tungstate, 
  and 
  

   the 
  covered 
  crucible 
  heated 
  with 
  a 
  very 
  low 
  flame 
  of 
  a 
  Bunsen 
  

   burner 
  waving 
  under 
  it. 
  After 
  driving 
  off 
  most 
  of 
  the 
  water, 
  

   the 
  crucible 
  was 
  heated 
  to 
  low 
  redness 
  and 
  the 
  mixture 
  fused, 
  

   cooled 
  and 
  weighed. 
  The 
  loss 
  apparently 
  corresponded 
  exactly 
  

   to 
  the 
  theoretical 
  loss 
  of 
  water 
  in 
  CuS0 
  4 
  .5H 
  2 
  0. 
  The 
  fusion 
  was 
  

   repeated 
  several 
  times 
  and 
  weighed 
  over 
  again, 
  but 
  no 
  further 
  

   loss 
  in 
  weight 
  was 
  found. 
  So 
  it 
  appears 
  that, 
  while 
  crystal- 
  

   line 
  copper 
  sulphate 
  loses 
  some 
  of 
  its 
  sulphur 
  trioxide 
  when 
  

   heated 
  by 
  itself 
  at 
  the 
  temperature 
  which 
  is 
  necessary 
  for 
  its 
  

   complete 
  dehydration, 
  no 
  loss 
  of 
  the 
  acidic 
  oxide 
  occurs 
  in 
  pres- 
  

   ence 
  of 
  sufficient 
  amount 
  of 
  neutral 
  sodium 
  tungstate 
  when 
  the 
  

   mixture 
  is 
  heated 
  over 
  a 
  Bunsen 
  flame 
  to 
  dull 
  red 
  heat. 
  It 
  is 
  

   possible 
  to 
  keep 
  the 
  mixture 
  in 
  quiet 
  fusion 
  for 
  fifteen 
  to 
  

   twenty 
  minutes 
  without 
  losing 
  any 
  sulphur 
  trioxide. 
  Sodium 
  

   tungstate 
  thus 
  serves 
  excellently 
  to 
  retain 
  the 
  sulphur 
  trioxide 
  

   at 
  a 
  temperature 
  sufficiently 
  high 
  to 
  dehydrate 
  the 
  sulphate 
  

   completely. 
  

  

  To 
  determine 
  the 
  water 
  of 
  crystallization 
  in 
  sulphates 
  by 
  

   weighing 
  the 
  water 
  evolved, 
  as 
  well 
  as 
  by 
  loss 
  on 
  ignition, 
  the 
  

   following 
  procedure 
  was 
  tried. 
  A 
  hard 
  glass 
  ignition 
  tube, 
  

   about 
  15 
  inches 
  long 
  and 
  1-J 
  inches 
  in 
  diameter, 
  was 
  placed 
  

   upon 
  a 
  small 
  furnace; 
  each 
  end 
  was 
  fitted 
  with 
  a 
  perforated 
  

   (one 
  hole) 
  rubber 
  stopper 
  soaked 
  in 
  hot 
  paraffine 
  for 
  a 
  moment 
  

   and 
  wiped 
  carefully 
  ; 
  and 
  one 
  end 
  of 
  it 
  was 
  connected 
  with 
  a 
  

   large 
  air-drying 
  apparatus 
  while 
  the 
  other 
  end 
  was 
  joined 
  to 
  a 
  

   sulphuric 
  acid 
  weighing 
  tube. 
  The 
  sulphuric 
  acid 
  tube 
  was 
  

   connected 
  to 
  a 
  calcium 
  chloride 
  drying 
  tube 
  to 
  prevent 
  the 
  

   entrance 
  of 
  any 
  moisture 
  into 
  the 
  weighing 
  tube 
  from 
  outside, 
  

   and 
  the 
  calcium 
  chloride 
  tube 
  was 
  connected 
  to 
  an 
  aspirator. 
  

   The 
  ignition 
  tube 
  was 
  thoroughly 
  dried 
  by 
  heating 
  it 
  for 
  at 
  

   least 
  forty-five 
  minutes 
  and 
  passing 
  a 
  rapid 
  current 
  of 
  dry 
  

   air 
  with 
  the 
  aid 
  of 
  the 
  aspirator. 
  The 
  efficiency 
  of 
  the 
  appa- 
  

   ratus 
  was 
  evident 
  from 
  the 
  fact 
  that 
  when, 
  after 
  such 
  drying, 
  

   the 
  sulphuric 
  acid 
  weighing 
  tube 
  was 
  connected 
  with 
  the 
  igni- 
  

   tion 
  tube 
  and 
  a 
  blank 
  test 
  made, 
  by 
  running 
  the 
  apparatus 
  for 
  

   one 
  hour, 
  a 
  gain 
  of 
  only 
  0*0003 
  gr. 
  in 
  the 
  weight 
  of 
  the 
  weigh- 
  

   ing 
  tube 
  resulted, 
  for 
  which 
  a 
  correction 
  was 
  applied 
  in 
  the 
  

   subsequent 
  work. 
  After 
  having 
  the 
  apparatus 
  thus 
  in 
  readi- 
  

   ness, 
  exactly 
  half 
  a 
  gram 
  of 
  the 
  sulphate 
  was 
  mixed 
  well 
  with 
  

   three 
  grams 
  of 
  sodium 
  tungstate 
  in 
  a 
  porcelain 
  boat, 
  ignited 
  

   and 
  weighed 
  previously. 
  The 
  boat 
  and 
  its 
  contents, 
  weighed 
  

   together, 
  were 
  introduced 
  into 
  the 
  ignition 
  tube. 
  The 
  ignition 
  

   was 
  started 
  at 
  first 
  very 
  gently 
  by 
  passing 
  a 
  current 
  of 
  hot 
  dry 
  

   air 
  over 
  the 
  boat, 
  at 
  a 
  rate 
  of 
  3 
  bubbles 
  a 
  second, 
  for 
  a 
  period 
  

   of 
  fifteen 
  minutes. 
  The 
  temperature 
  was 
  carefully 
  and 
  gradu- 
  

  

  