﻿480 
  F. 
  A. 
  Perret 
  — 
  Volcanic 
  Research 
  at 
  Kilauea. 
  

  

  and, 
  when 
  this 
  was 
  immersed, 
  gave, 
  with 
  the 
  correction 
  for 
  the 
  

   cold-end 
  temperature, 
  1050° 
  C. 
  The 
  cold-end 
  temperature 
  

   was 
  taken 
  as 
  being 
  virtually 
  100° 
  C 
  from 
  the 
  writer's 
  observa- 
  

   tion 
  of 
  steam 
  issuing 
  strongly 
  from 
  the 
  water 
  jacket 
  (neglecting 
  

   altitude). 
  The 
  instrument 
  was 
  quickly 
  withdrawn 
  from 
  the 
  

   lava 
  — 
  its 
  tube 
  already 
  almost 
  gone 
  — 
  and, 
  in 
  a 
  second 
  immer- 
  

   sion, 
  was 
  engulfed 
  by 
  a 
  fountain 
  and 
  lost. 
  

  

  The 
  temperature 
  reading 
  thus 
  obtained 
  agrees 
  with 
  the 
  vis- 
  

   ual 
  estimate 
  of 
  Dr. 
  Shepherd, 
  whose 
  experience 
  in 
  furnace 
  

   work 
  has 
  given 
  him 
  a 
  special 
  aptitude 
  in 
  this 
  direction. 
  The 
  

   writer 
  had 
  estimated 
  the 
  fountains 
  at 
  slightly 
  over 
  1100° 
  C, 
  

   and 
  it 
  may 
  be 
  that 
  this 
  difference 
  actually 
  exists 
  between 
  the 
  

   fountains 
  and 
  the 
  still 
  lava 
  beneath 
  a 
  crust, 
  although 
  it 
  is 
  con- 
  

   trary 
  to 
  all 
  the 
  writer's 
  experience 
  that 
  there 
  should 
  be 
  any 
  

   very 
  considerable 
  difference 
  of 
  temperature 
  in 
  different 
  parts 
  

   of 
  a 
  mass 
  of 
  fully 
  liquid 
  lava, 
  even 
  in 
  the 
  case 
  of 
  a 
  long, 
  flow- 
  

   ing 
  stream. 
  

  

  It 
  is, 
  at 
  all 
  events, 
  quite 
  obvious 
  that 
  the 
  heat 
  of 
  Kilauean 
  

   lava 
  has 
  been 
  generally 
  overestimated 
  in 
  the 
  past. 
  " 
  White 
  

   heat" 
  is 
  a 
  convenient 
  expression, 
  and 
  is 
  a 
  condition 
  easily 
  imag- 
  

   ined 
  in 
  contrast 
  with 
  dark 
  surroundings 
  of 
  a 
  warm 
  tint, 
  but 
  a 
  

   tungsten 
  pocket 
  lamp 
  will 
  quickly 
  dispel 
  the 
  illusion. 
  

  

  Dr. 
  Shepherd, 
  on 
  his 
  second 
  visit 
  to 
  Kilauea, 
  had 
  the 
  privi- 
  

   lege 
  of 
  witnessing 
  one 
  of 
  those 
  phenomenal 
  increases 
  of 
  activ- 
  

   ity 
  which 
  fill 
  the 
  pit 
  from 
  side 
  to 
  side 
  with 
  a 
  lake 
  of 
  boiling 
  

   lava 
  without 
  a 
  trace 
  of 
  crust, 
  yet 
  the 
  temperature 
  fell 
  short 
  of 
  

   1200° 
  C. 
  

  

  A 
  curious 
  observation 
  by 
  the 
  present 
  writer 
  goes 
  far, 
  how- 
  

   ever, 
  towards 
  explaining 
  the 
  many 
  references 
  to 
  white 
  heat. 
  

   During 
  the 
  first 
  few 
  nights 
  of 
  his 
  stay 
  at 
  the 
  crater 
  he 
  was, 
  

   himself, 
  impressed 
  by 
  sudden 
  apparent 
  increases 
  in 
  the 
  tem- 
  

   perature 
  of 
  the 
  lava 
  as 
  shown 
  by 
  a 
  change 
  from 
  the 
  golden 
  

   glow 
  to 
  a 
  whitish 
  incandescence. 
  There 
  being 
  no 
  other 
  indi- 
  

   cations 
  of 
  greater 
  activity 
  which 
  might 
  account 
  for 
  this 
  phe- 
  

   nomenon, 
  he 
  continued 
  to 
  observe 
  the 
  lake 
  and 
  found 
  that, 
  at 
  

   times, 
  this 
  whiteness 
  appeared 
  in 
  places 
  while 
  the 
  rest 
  of 
  the 
  

   lava 
  retained 
  its 
  original 
  color. 
  This 
  clearly 
  indicated 
  a 
  cause 
  

   other 
  than 
  temperature 
  variation, 
  and 
  a 
  little 
  further 
  study 
  

   resolved 
  the 
  mystery. 
  In 
  the 
  paper 
  on 
  lava 
  fountains 
  refer- 
  

   ence 
  was 
  made 
  to 
  the 
  gases 
  which, 
  on 
  issuing 
  from 
  the 
  lava, 
  

   burn 
  in 
  the 
  air 
  with 
  a 
  visible 
  flame 
  and 
  the 
  production 
  of 
  a 
  

   cloud 
  of 
  the 
  burnt 
  vapors. 
  These 
  vapors, 
  although 
  transpar- 
  

   ent, 
  have, 
  by 
  reflected 
  daylight, 
  a 
  bluish 
  tint, 
  but 
  when 
  viewed 
  

   by 
  transmitted 
  light 
  are 
  of 
  a 
  yellowish 
  brown 
  or 
  reddish 
  browm 
  

   color, 
  according 
  to 
  their 
  density 
  — 
  a 
  color 
  and 
  a 
  quality 
  which 
  

   is 
  highly 
  absorptive 
  of 
  those 
  orange 
  and 
  yellow 
  rays 
  so 
  abun- 
  

   dant 
  in 
  the 
  golden-hued 
  lava. 
  Seen 
  at 
  night 
  through 
  a 
  veil 
  of 
  

   this 
  transparent 
  vapor, 
  the 
  glowing 
  liquid, 
  although 
  somewhat 
  

  

  