﻿486 
  F. 
  A. 
  Ferret 
  — 
  Volcanic 
  Research 
  at 
  Kilauea. 
  

  

  The 
  quantity 
  given 
  off 
  from 
  1 
  kilogram 
  of 
  lava 
  depends 
  on 
  the 
  

   quantity 
  of 
  water. 
  I 
  obtained 
  4000 
  to 
  6000 
  cubic 
  cent. 
  

  

  It 
  is 
  advisable 
  to 
  remark, 
  that 
  the 
  quantity 
  of 
  gases 
  collected 
  is 
  

   enormously 
  greater 
  than 
  that 
  obtained 
  by 
  the 
  study 
  of 
  the 
  appar- 
  

   ent 
  density 
  of 
  the 
  natural 
  vesiculated 
  lava. 
  In 
  our 
  experiment 
  

   the 
  water 
  oxidizes 
  the 
  lava 
  continually 
  until 
  the 
  chemical 
  equili- 
  

   brium 
  is 
  reached. 
  This 
  reaction, 
  which 
  we 
  accomplished 
  in 
  the 
  

   laboratory, 
  does 
  not 
  take 
  place 
  in 
  the 
  magma 
  of 
  the 
  volcano, 
  for 
  

   the 
  latter 
  contains 
  a 
  residue 
  of 
  carbon. 
  Therefore, 
  if 
  there 
  was 
  

   any 
  steam, 
  it 
  was 
  in 
  too 
  small 
  a 
  quantity 
  to 
  attack 
  all 
  the 
  C. 
  The 
  

   proportion 
  reached 
  so 
  low 
  a 
  limit 
  that 
  it 
  is 
  almost 
  nothing. 
  

  

  This 
  enables 
  us 
  to 
  say 
  : 
  that 
  the 
  magma 
  of 
  Kilauea 
  is 
  anhy- 
  

   dric, 
  with 
  the 
  exception 
  of 
  the 
  enclaves, 
  and 
  in 
  special 
  cases, 
  (as 
  

   explained 
  in 
  my 
  Recherches 
  sur 
  l'Exhalaison 
  volcanique, 
  p. 
  264,) 
  

   it 
  even 
  seems 
  that 
  this 
  proposition 
  maybe 
  extended 
  to 
  the 
  ancient 
  

   magmas, 
  such 
  as 
  granites. 
  For 
  we 
  know 
  that 
  white 
  and 
  black 
  

   micas 
  are 
  not 
  chemically 
  hydrated 
  minerals, 
  as 
  has 
  hitherto 
  been 
  

   admitted. 
  For 
  the 
  details 
  concerning 
  this 
  proposition, 
  which 
  

   seem 
  to 
  be 
  extraordinary, 
  see 
  Bulletin 
  de 
  la 
  Societe 
  mineralogique 
  

   de 
  France, 
  Feb., 
  1913, 
  and 
  Archives 
  des 
  Sciences, 
  Geneve, 
  xxv, 
  

   No. 
  5. 
  

  

  Crystallization. 
  — 
  We 
  wish 
  to 
  draw 
  attention 
  to 
  the 
  interesting 
  

   point 
  brought 
  to 
  light 
  by 
  Mr. 
  Perret's 
  skilful 
  experiment. 
  The 
  

   lava 
  was 
  indeed 
  collected 
  at 
  the 
  very 
  time 
  of 
  its 
  volcanic 
  and 
  

   crystalline 
  evolution 
  ; 
  as 
  before 
  explained, 
  a 
  fairly 
  large 
  mass 
  of 
  

   lava 
  was 
  extracted 
  from 
  the 
  " 
  Old 
  Faithful." 
  When 
  he 
  got 
  the 
  

   lava 
  in 
  fusion, 
  from 
  the 
  pit, 
  Mr. 
  Perret 
  brought 
  up 
  a 
  glass 
  in 
  

   which 
  some 
  crystals 
  were 
  floating 
  (labradorite, 
  peridot, 
  and 
  more 
  

   rarely 
  augite 
  of 
  old 
  formation). 
  Several 
  of 
  these 
  crystals 
  are 
  in 
  

   the 
  course 
  of 
  digestion. 
  They 
  are 
  corroded 
  and 
  the 
  edges 
  rounded, 
  

   which 
  shows 
  them 
  to 
  be 
  debris 
  of 
  enclaves. 
  Other 
  crystals 
  have 
  

   clear 
  cut 
  and 
  sharp 
  angles 
  : 
  they 
  probably 
  are 
  in 
  the 
  course 
  of 
  

   formation. 
  

  

  The 
  external 
  part 
  of 
  the 
  block, 
  cooled 
  suddenly, 
  was 
  consoli- 
  

   dated 
  into 
  a 
  limpid 
  yellowish-green 
  glass. 
  The 
  internal 
  part, 
  cool- 
  

   ing 
  more 
  slowly, 
  crystallized. 
  There 
  were 
  no 
  real 
  crystals, 
  but 
  

   trichitic-centroradiated 
  spherulites. 
  These 
  trichites 
  are 
  generally 
  

   developed 
  around 
  a 
  preexisting 
  crystal 
  ; 
  they 
  form 
  around 
  it 
  a 
  

   dark-colored 
  hairy 
  setting, 
  opaque 
  in 
  the 
  center 
  and 
  transparent 
  at 
  

   the 
  edges. 
  The 
  refractive 
  index 
  is 
  greater 
  than 
  that 
  of 
  glass. 
  

   The 
  fibers 
  are 
  extremely 
  fine, 
  delicate 
  and 
  indistinct 
  in 
  form. 
  It 
  is 
  

   easy 
  to 
  recognise, 
  with 
  polarized 
  light, 
  the 
  characters 
  of 
  a 
  spher- 
  

   ulite, 
  the 
  fibers 
  of 
  which 
  are 
  elongated 
  optically 
  + 
  (positive). 
  

  

  It 
  is 
  impossible 
  to 
  say 
  whether 
  a 
  pure 
  mineral 
  is 
  present. 
  We 
  

   are. 
  in 
  presence 
  of 
  an 
  intermediate 
  state 
  of 
  crystalline 
  evolution. 
  

   This 
  phenomenon 
  appears 
  in 
  a 
  very 
  short 
  space 
  of 
  time 
  — 
  a 
  few 
  

   hours. 
  We 
  must 
  be 
  grateful 
  to 
  Mr. 
  Perret 
  for 
  having 
  demon- 
  

   strated 
  experimentally, 
  on 
  the 
  volcano 
  itself, 
  this 
  interesting 
  epoch 
  

   in 
  the 
  life 
  of 
  the 
  lava. 
  

  

  