﻿174 
  C. 
  Barus 
  — 
  Hot 
  Water 
  and 
  Soft 
  Glass 
  

  

  the 
  thermal 
  data 
  sought 
  is 
  almost 
  bound 
  to 
  prove 
  futile. 
  

   There 
  is 
  so 
  little 
  opportunity 
  favoring 
  the 
  accumulation 
  of 
  

   heat. 
  

  

  In 
  nature, 
  where 
  a 
  large 
  extent 
  of 
  rock 
  is 
  liable 
  to 
  be 
  placed 
  

   under 
  the 
  influence 
  of 
  water 
  at 
  high 
  temperatures, 
  the 
  condi- 
  

   tions 
  are 
  much 
  better 
  adapted 
  to 
  promote 
  solution. 
  Let 
  it 
  be 
  

   called 
  to 
  mind 
  that 
  the 
  rate 
  of 
  reaction 
  increases 
  rapidly 
  with 
  

   increasing 
  temperature, 
  i. 
  e., 
  with 
  increasing 
  depth 
  below 
  the 
  

   surface 
  of 
  the 
  earth. 
  Furthermore, 
  that 
  whatever 
  heat 
  is. 
  

   produced 
  by 
  the 
  reaction 
  itself, 
  will 
  in 
  its 
  turn 
  additionally 
  

   stimulate 
  its 
  intensity. 
  Hence 
  it 
  is 
  altogether 
  probable 
  that 
  at 
  

   sufficient 
  depths 
  within 
  the 
  earth, 
  the 
  heat 
  evolved 
  by 
  the 
  

   action 
  of 
  water 
  on 
  rock 
  will 
  be 
  generated 
  faster 
  than 
  it 
  can 
  be 
  

   dissipated. 
  The 
  result 
  would 
  be 
  a 
  subterranean, 
  local 
  source 
  

   of 
  heat 
  whose 
  efficiency 
  is 
  variable 
  with 
  the 
  character 
  of 
  the 
  

   rock, 
  the 
  topography 
  of 
  the 
  surface, 
  the 
  temperature 
  and 
  depth 
  

   of 
  the 
  available 
  mass 
  of 
  water, 
  etc. 
  If 
  we 
  endeavor 
  to 
  associate 
  

   volcanic 
  action 
  with 
  some 
  such 
  agency 
  as 
  here 
  sketched, 
  we 
  

   should 
  agree 
  that 
  the 
  occurrence 
  of 
  volcanoes 
  at 
  the 
  sea 
  shores 
  

   presents 
  the 
  case 
  of 
  greater 
  probability, 
  while 
  inland 
  volcanoes 
  

   are 
  not 
  excluded. 
  The 
  probability 
  would 
  increase 
  for 
  those 
  

   rarer 
  cases 
  in 
  which 
  the 
  necessary 
  quantity 
  of 
  water 
  is 
  in 
  any 
  

   accidental 
  way 
  liable 
  to 
  reach 
  the 
  quantity 
  and 
  special 
  kind 
  of 
  

   rock 
  in 
  question. 
  Even 
  under 
  suitable 
  conditions 
  of 
  tempera- 
  

   ture 
  therefore, 
  and 
  near 
  the 
  ocean, 
  active 
  volcanoes 
  would 
  be 
  

   a 
  rare 
  occurrence, 
  seeing 
  that 
  the 
  particular 
  ingredients 
  needed 
  

   for 
  an 
  intense 
  reaction 
  are 
  not 
  everywhere 
  available. 
  Nor 
  is 
  

   it 
  necessary 
  that 
  the 
  material 
  ejected 
  by 
  the 
  volcano 
  be 
  the 
  

   identical 
  rock 
  acted 
  on, 
  since 
  in 
  the 
  above 
  experiments 
  with 
  

   retorts, 
  dissociations 
  are 
  already 
  in 
  evidence. 
  The 
  material 
  

   which 
  ultimately 
  remains 
  hydrated 
  will 
  depend 
  on 
  other 
  reac- 
  

   tions 
  and 
  segregations, 
  possible 
  after 
  termination 
  of 
  the 
  hydra- 
  

   tion, 
  or 
  upon 
  reactions 
  within 
  the 
  hydrated 
  magma. 
  

  

  Finally 
  with 
  the 
  completed 
  hydration 
  of 
  the 
  given 
  silicate 
  

   in 
  the 
  manner 
  evidenced 
  by 
  the 
  above 
  experiments 
  with 
  capil- 
  

   lary 
  tubes; 
  in 
  other 
  words, 
  after 
  the 
  available 
  water 
  or 
  rock 
  

   have 
  been 
  used 
  up, 
  the 
  reaction 
  would 
  definitely 
  subside 
  and 
  

   the 
  volcano 
  become 
  extinct. 
  

  

  It 
  is 
  not 
  necessary 
  to 
  trespass 
  speculatively 
  as 
  far 
  as 
  I 
  have 
  

   done 
  in 
  the 
  preceding 
  paragraph 
  to 
  detect 
  the 
  definite 
  bearing 
  

   of 
  the 
  present 
  results 
  on 
  the 
  potential 
  fluidity 
  of 
  magmas, 
  their 
  

   diminished 
  density, 
  etc. 
  I 
  will 
  give 
  a 
  rough 
  sketch 
  of 
  the 
  

   geologic 
  conditions 
  involved 
  to 
  make 
  my 
  meaning 
  clearer. 
  A 
  

   represents 
  a 
  vertical 
  section 
  of 
  the 
  ocean 
  with 
  the 
  depths 
  laid 
  off 
  in 
  

   kilometers. 
  As 
  the 
  water 
  put 
  into 
  reaction 
  must 
  remain 
  liquid 
  

   at 
  least 
  up 
  to 
  200° 
  (say), 
  the 
  water 
  available 
  for 
  the 
  reaction 
  

   must 
  be 
  tapped 
  from 
  a 
  level 
  deeper 
  than 
  150 
  meters, 
  or 
  roughly 
  

  

  