﻿52 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  3 
  

  

  The 
  ammonia 
  was 
  determined 
  by 
  the 
  direct 
  distillation 
  of 
  the 
  sam- 
  

   ple 
  in 
  the 
  customary 
  Kjeldahl 
  apparatus. 
  A 
  gram 
  sample 
  was 
  dis- 
  

   solved 
  in 
  a 
  500 
  cc. 
  Kjeldahl 
  flask 
  with 
  150 
  cc. 
  of 
  distilled 
  water, 
  an 
  

   excess 
  strong 
  NaOH 
  solution 
  was 
  then 
  added 
  witb 
  the 
  usual 
  precau- 
  

   tions 
  and 
  75 
  cc. 
  of 
  distillate 
  were 
  slowly 
  received 
  into 
  25 
  cc. 
  N/10 
  H2SO4. 
  

  

  The 
  excess 
  of 
  acid 
  in 
  the 
  distillate 
  was 
  titrated 
  with 
  N/10 
  NaOH 
  

   solution, 
  using 
  methyl 
  orange 
  indicator, 
  the 
  neutralization 
  value 
  of 
  the 
  

   distilled 
  ammonia 
  being 
  obtained 
  by 
  difference 
  and 
  its 
  percentage 
  

   computed. 
  Duplicate 
  determinations 
  agreed 
  closely 
  and 
  were 
  cor- 
  

   rected 
  for 
  a 
  blank 
  test 
  made 
  on 
  all 
  reagents 
  used. 
  

  

  The 
  mineral 
  was 
  dried 
  to 
  constant 
  weights 
  at 
  temperature 
  intervals 
  

   between 
  105° 
  C. 
  and 
  410° 
  C. 
  inclusive, 
  with 
  the 
  following 
  results. 
  At 
  

   105° 
  C. 
  a 
  loss 
  of 
  36.48 
  per 
  cent 
  was 
  obtained, 
  which 
  is 
  slightly 
  over 
  

   three-fourths 
  of 
  the 
  total 
  percentage 
  of 
  water. 
  At 
  200° 
  C. 
  the 
  remain- 
  

   ing 
  water, 
  excepting 
  about 
  one 
  per 
  cent 
  of 
  the 
  total, 
  was 
  given 
  off. 
  

   At 
  350° 
  C. 
  a 
  few 
  tenths 
  of 
  one 
  per 
  cent 
  of 
  water 
  are 
  still 
  retained 
  in 
  

   the 
  residue. 
  Losses 
  in 
  excess 
  of 
  the 
  actual 
  percentage 
  of 
  water 
  com- 
  

   menced 
  near 
  360° 
  C. 
  and 
  became 
  about 
  three 
  per 
  cent 
  at 
  410° 
  C. 
  

   Evidently 
  ammonium 
  sulfate 
  in 
  the 
  double 
  compound 
  commences 
  de- 
  

   composition 
  near 
  360° 
  C. 
  which 
  is 
  about 
  80° 
  C. 
  higher 
  than 
  the 
  

   decomposition 
  temperature 
  of 
  pure 
  ammonium 
  sulfate. 
  

  

  TABLE 
  2. 
  — 
  The 
  Loss 
  Obtained 
  by 
  Heating 
  Tschermigite 
  

  

  The 
  strongly 
  ignited 
  residue 
  gave 
  a 
  total 
  loss 
  of 
  88.06 
  per 
  cent. 
  

   This 
  loss 
  consisted 
  of 
  the 
  water 
  and 
  ammonia 
  [(NH4)20] 
  content 
  to- 
  

   gether 
  with 
  nearly 
  all 
  of 
  the 
  sulfuric 
  anhydride, 
  a 
  slight 
  amount 
  

   (0.10) 
  being 
  retained. 
  

  

  In 
  order 
  to 
  interpret 
  correctly 
  the 
  function 
  of 
  the 
  small 
  quantity 
  

   of 
  substances 
  besides 
  AI2O3, 
  retained 
  in 
  the 
  ignited 
  residue, 
  some 
  com- 
  

   parative 
  experiments 
  with 
  a 
  prepared 
  sodium 
  alum 
  were 
  carried 
  out. 
  

   The 
  percentage 
  of 
  strongly 
  ignited 
  residue 
  from 
  sodium 
  alum 
  was 
  

   found 
  to 
  be 
  nearly 
  identical 
  with 
  the 
  sum 
  of 
  the 
  percentages 
  of 
  Na20 
  

  

  