﻿96 
  Mack 
  and 
  Hulett 
  — 
  Water 
  Content 
  of 
  Coal. 
  

  

  actions 
  in 
  the 
  peat 
  were 
  taking 
  place. 
  In 
  working 
  above 
  

   100° 
  C. 
  it 
  was 
  of 
  course 
  necessary 
  to 
  maintain 
  the 
  pressure 
  at 
  

   or 
  above 
  that 
  of 
  the 
  vapor 
  pressure 
  of 
  the 
  water 
  in 
  order 
  to 
  

   keep 
  the 
  water 
  in 
  the 
  liquid 
  state, 
  but 
  we 
  fail 
  to 
  see 
  that 
  the 
  

   pressure 
  played 
  an} 
  7 
  role 
  in 
  the 
  chemical 
  reactions. 
  

  

  The 
  interesting 
  point 
  of 
  Bergius' 
  work 
  is 
  that 
  he 
  showed 
  

   that 
  the 
  same 
  product 
  was 
  obtained 
  by 
  heating 
  for 
  8 
  hours 
  at 
  

   310°, 
  as 
  for 
  heating 
  64 
  hours 
  at 
  310°. 
  In 
  other 
  words 
  the 
  rate 
  

   of 
  reaction 
  was 
  doubled 
  for 
  every 
  rise 
  of 
  10°, 
  which 
  is 
  the 
  

   characteristic 
  increase 
  of 
  rate 
  for 
  chemical 
  reactions. 
  On 
  this 
  

   basis, 
  assuming 
  that 
  the 
  chemical 
  changes 
  involved 
  in 
  the 
  

   transformation 
  of 
  peat 
  to 
  coal 
  in 
  the 
  natural 
  process 
  took 
  place 
  

   at 
  the 
  average 
  temperature 
  of 
  10° 
  C, 
  Bergius 
  calculated 
  that 
  to 
  

   form 
  bituminous 
  coal 
  from 
  peat, 
  2 
  33 
  X 
  8 
  hours 
  was 
  the 
  time 
  

   required, 
  or 
  about 
  8 
  million 
  years, 
  an 
  estimate 
  in 
  good-enough 
  

   agreement 
  with 
  the 
  calculations 
  of 
  the 
  geologists. 
  Bergius 
  

   gives 
  this 
  figure 
  with 
  all 
  " 
  due 
  reserve," 
  but 
  it 
  will 
  readily 
  be 
  

   seen 
  that 
  this 
  line 
  of 
  evidence, 
  while 
  perhaps 
  not 
  absolutely 
  

   conclusive, 
  gives 
  very 
  strong 
  support 
  to 
  the 
  idea 
  that 
  the 
  

   transformation 
  of 
  peat 
  to 
  coal 
  was 
  the 
  result 
  of 
  a 
  series 
  of 
  slow 
  

   chemical 
  changes 
  proceeding 
  at 
  about 
  the 
  same 
  temperature 
  as 
  

   the 
  earth's 
  surface, 
  and 
  quite 
  independent 
  of 
  the 
  presence 
  or 
  

   absence 
  of 
  pressure. 
  

  

  Bergius 
  showed 
  that 
  vegetable 
  matter 
  or 
  peat 
  could 
  be 
  

   changed 
  to 
  a 
  residue 
  having 
  the 
  same 
  composition 
  as 
  bituminous 
  

   coal, 
  by 
  reactions 
  which 
  require 
  a 
  definite 
  " 
  temperature-time 
  " 
  

   interval, 
  but 
  the 
  product 
  was 
  an 
  amorphous 
  powder 
  when 
  

   separated 
  from 
  the 
  water. 
  Bergius 
  further 
  showed 
  that 
  this 
  

   residue 
  could 
  be 
  transformed 
  to 
  a 
  substance 
  having 
  not 
  only 
  

   the 
  chemical 
  composition 
  but 
  also 
  the 
  texture 
  and 
  properties 
  

   of 
  anthracite, 
  by 
  subjecting 
  it 
  to 
  a 
  temperature 
  of 
  340° 
  and 
  a 
  

   pressure 
  of 
  5000 
  atmospheres 
  for 
  some 
  time. 
  At 
  this 
  tempera- 
  

   ture 
  the 
  chemical 
  changes 
  were 
  quite 
  rapid 
  and 
  the 
  residues 
  

   were 
  compressed 
  to 
  a 
  substance 
  with 
  the 
  hardness 
  of 
  anthracite. 
  

   It 
  is 
  quite 
  possible 
  that 
  both 
  a 
  great 
  pressure 
  and 
  a 
  high 
  

   temperature, 
  considerably 
  above 
  ordinary 
  rock 
  temperature, 
  

   have 
  played 
  a 
  role 
  in 
  the 
  formation 
  of 
  our 
  anthracite 
  coals. 
  

   The 
  comparative 
  suddenness 
  in 
  the 
  change, 
  from 
  a 
  chemical 
  

   standpoint, 
  from 
  bituminous 
  to 
  anthracite 
  coal, 
  is 
  indicated 
  

   in 
  the 
  graphical 
  studies 
  of 
  the 
  Ultimate 
  Analyses 
  of 
  Coal,* 
  

   and 
  is 
  in 
  line 
  with 
  these 
  results 
  of 
  Bergius. 
  

  

  It 
  is 
  not 
  necessary 
  to 
  assume 
  either 
  pressure 
  or 
  any 
  higher 
  

   temperature 
  than 
  ordinary 
  rock 
  temperature 
  for 
  the 
  trans- 
  

   formation 
  of 
  peat 
  through 
  the 
  various 
  forms 
  of 
  coal 
  to 
  bitu- 
  

   minous 
  coal. 
  The 
  cellulose 
  and 
  protein 
  substances 
  of 
  the 
  

   original 
  vegetable 
  matter 
  are 
  gradually 
  changed 
  by 
  the 
  action 
  

  

  * 
  Ralston, 
  Tech. 
  Paper, 
  93, 
  U. 
  S. 
  Bureau 
  of 
  Mines, 
  1915. 
  

  

  