﻿Mack 
  and 
  Hidett 
  — 
  Water 
  Content 
  of 
  Goal. 
  

  

  103 
  

  

  observations 
  and 
  shows 
  that 
  a 
  temperature 
  even 
  less 
  than 
  250° 
  

   for 
  a 
  reasonable 
  time 
  is 
  sufficient 
  for 
  our 
  purpose. 
  

  

  Our 
  first 
  experiments 
  were 
  carried 
  out 
  with 
  a 
  very 
  simple 
  

   apparatus. 
  A 
  glass 
  " 
  alembic 
  J1 
  of 
  the 
  form 
  shown 
  in 
  fig. 
  1 
  was 
  

   weighed, 
  and 
  after 
  the 
  lower 
  bulb 
  (5 
  CC 
  capacity) 
  was 
  filled 
  with 
  

   coal, 
  it 
  was 
  reweighed 
  to 
  get 
  the 
  weight 
  of 
  coal. 
  The 
  tube 
  

   was 
  now 
  evacuated 
  to 
  about 
  2 
  mm 
  pressure 
  and 
  sealed 
  off. 
  A 
  

   split 
  cork 
  just 
  below 
  the 
  alembic 
  bulb 
  served 
  to 
  hold 
  the 
  lower 
  

  

  Fig. 
  2. 
  

  

  2.0- 
  

  

  230° 
  

  

  

  

  9 
  

  

  u- 
  

  

  184- 
  

  

  

  

  

  

  

  no" 
  

  

  

  12-- 
  

  

  

  

  

  

  

  

  111" 
  ^ 
  

  

  

  

  

  

  New 
  Ki.ver 
  Coil 
  

  

  go*- 
  

  

  

  

  

  — 
  — 
  — 
  ir 
  

  

  10 
  

  

  eo 
  

  

  30 
  40 
  

  

  Mi.-n.utes 
  

  

  SO 
  

  

  60 
  

  

  70 
  

  

  SO 
  

  

  bulb 
  and 
  tube 
  in 
  a 
  vapor 
  bath, 
  — 
  where 
  the 
  condensation 
  of 
  

   vapor 
  on 
  the 
  coal 
  bulb 
  not 
  only 
  rapidly 
  brought 
  it 
  to 
  the 
  tem- 
  

   perature 
  of 
  the 
  bath, 
  but 
  maintained 
  the 
  temperature 
  accu- 
  

   rately 
  and 
  easily. 
  The 
  moisture 
  from 
  the 
  coal 
  rapidly 
  

   evaporated 
  and 
  condensed 
  in 
  the 
  alembic 
  bulb, 
  which 
  was 
  

   cooled 
  by 
  ice 
  or 
  a 
  jacket 
  with 
  ice-salt 
  mixtures. 
  After 
  a 
  sam- 
  

   ple 
  of 
  coal 
  had 
  been 
  heated 
  for 
  a 
  definite 
  time, 
  the 
  apparatus 
  

   was 
  removed 
  from 
  the 
  bath, 
  the 
  tube 
  was 
  cut 
  just 
  below 
  the 
  

   alembic 
  bulb 
  and 
  by 
  weighing, 
  removing 
  the 
  water 
  and 
  again 
  

   weighing, 
  the 
  water 
  was 
  determined. 
  A 
  little 
  glass-blowing 
  

   permitted 
  of 
  using 
  the 
  same 
  tubes 
  again. 
  It 
  was 
  found 
  to 
  be 
  

   necessary 
  to 
  cool 
  the 
  coal 
  bulb 
  in 
  a 
  freezing 
  mixture 
  to 
  pre- 
  

   vent 
  loss 
  of 
  moisture 
  on 
  evacuating; 
  at 
  —20° 
  the 
  loss 
  was 
  

   negligible. 
  When 
  all 
  these 
  precautions 
  were 
  taken 
  it 
  was 
  

   found 
  possible 
  to 
  duplicate 
  a 
  result 
  to 
  0*2 
  to 
  0*5 
  per 
  cent 
  of 
  

   the 
  amount 
  of 
  water 
  determined. 
  

  

  With 
  this 
  apparatus 
  we 
  studied 
  the 
  per 
  cent 
  of 
  water 
  lost 
  

   by 
  a 
  given 
  coal 
  for 
  different 
  periods 
  of 
  heating, 
  obtaining 
  an 
  

   isothermal 
  with 
  percentage 
  of 
  water 
  as 
  a 
  function 
  of 
  time, 
  the 
  

   curve 
  showing 
  a 
  flattening 
  when 
  the 
  loss 
  of 
  water 
  finally 
  in 
  

  

  