﻿BARREN 
  ISLAND. 
  17 
  

  

  The 
  cone 
  is 
  almost 
  completely 
  bare 
  of 
  vegetation, 
  the 
  few 
  tufts 
  of 
  

   grass, 
  &c, 
  which 
  have 
  managed 
  to 
  secure 
  a 
  footing, 
  being 
  mainly 
  on 
  the 
  

   north 
  side, 
  where 
  the 
  ash 
  is 
  partly 
  protected 
  from 
  the 
  heat 
  of 
  the 
  sun, 
  and 
  

   consequently 
  not 
  so 
  completely 
  desiccated. 
  On 
  the 
  western 
  slope, 
  especi- 
  

   ally, 
  the 
  blaze 
  of 
  .sunshine 
  in 
  the 
  afternoon 
  raises 
  the 
  black 
  ash 
  to 
  such 
  a 
  

   temperature 
  that 
  it 
  can 
  scarcely 
  be 
  touched 
  with 
  the 
  hand. 
  It 
  is 
  to 
  the 
  

   extreme 
  aridity, 
  and 
  shifting 
  character, 
  of 
  the 
  loose 
  materials 
  that 
  the 
  

   absence 
  of 
  vegetation 
  is 
  due, 
  and 
  only 
  locally, 
  in 
  the 
  neighbourhood 
  of 
  

   the 
  solfataras, 
  to 
  volcanic 
  emanations. 
  Indeed, 
  there 
  is 
  more 
  vegetation 
  

   about 
  parts 
  of 
  the 
  crater 
  than 
  elsewhere, 
  some 
  little 
  ferns, 
  &c, 
  growing 
  

   under 
  the 
  shelter 
  of 
  the 
  rocks, 
  in 
  the 
  moist 
  atmosphere 
  produced 
  by 
  the 
  

   issuing 
  steam. 
  

  

  The 
  crater 
  is 
  of 
  an 
  ovoid 
  form 
  (the 
  northern 
  edge 
  of 
  which 
  is, 
  

  

  however, 
  straighter 
  than 
  the 
  southern) 
  with 
  the 
  

   The 
  recent 
  crater. 
  . 
  . 
  . 
  

  

  major 
  axis 
  lying 
  about 
  S. 
  by 
  W 
  . 
  — 
  N. 
  by 
  L. 
  The 
  

  

  highest 
  points 
  of 
  the 
  edge, 
  to 
  the 
  north 
  and 
  south, 
  are 
  78 
  feet 
  above 
  

   the 
  floor 
  of 
  the 
  crater, 
  while 
  to 
  the 
  east 
  there 
  is 
  a 
  depression, 
  where 
  the 
  

   edge 
  is 
  only 
  22 
  feet 
  above 
  the 
  same 
  level. 
  To 
  the 
  west 
  there 
  is 
  a 
  minor 
  

   depression, 
  38 
  feet 
  above 
  the 
  floor. 
  The 
  materials 
  inside 
  the 
  crater 
  are 
  

   loose 
  blocks 
  of 
  lava, 
  scoriae 
  and 
  ash, 
  but 
  to 
  the 
  south-west 
  of 
  the 
  crater- 
  

   bottom 
  there 
  is 
  a 
  mass 
  of 
  solid 
  lava, 
  which 
  is 
  probably 
  in 
  connection 
  

   with 
  a 
  flow 
  down 
  the 
  side 
  of 
  the 
  cone 
  which 
  has 
  been 
  covered 
  over 
  by 
  

   the 
  latest 
  eruption 
  of 
  fragmentary 
  material. 
  The 
  floor 
  of 
  the 
  crater, 
  

   which 
  is 
  60 
  feet 
  in 
  diameter, 
  is 
  a 
  level 
  plain 
  of 
  sand, 
  washed 
  down 
  from 
  

   the 
  slopes 
  above. 
  If 
  a 
  heavy 
  stone 
  be 
  dropped 
  on 
  it 
  there 
  is 
  a 
  hollow 
  

   kind 
  of 
  reverberation, 
  which 
  reminds 
  one 
  of 
  the 
  similar 
  phenomenon 
  at 
  

   the 
  solfatara 
  near 
  Puzzuoli. 
  On 
  the 
  edge 
  of 
  the 
  crater, 
  in 
  the 
  depression 
  

   to 
  the 
  west, 
  there 
  is 
  an 
  immense 
  ejected 
  block 
  of 
  lava 
  22 
  feet 
  long, 
  11 
  

   broad, 
  and 
  varying 
  in 
  height 
  between 
  13 
  and 
  19 
  feet. 
  1 
  It 
  can 
  be 
  plainly 
  

   seen 
  from 
  the 
  landing-place, 
  forming 
  (as 
  may 
  be 
  noticed 
  in 
  the 
  frontis- 
  

  

  '"I 
  am 
  indebted 
  for 
  these 
  figures 
  to 
  Dr. 
  J. 
  Reid, 
  who 
  accompanied 
  us 
  during 
  a 
  portion 
  of 
  

   our 
  expedition. 
  Enormous 
  as 
  this 
  block 
  is, 
  it 
  must 
  be 
  remembered 
  that 
  it 
  was 
  hurled 
  to 
  

   but 
  a 
  trifling 
  horizontal 
  distance, 
  and 
  probably 
  to 
  a 
  very 
  small 
  vertical 
  height. 
  

  

  b 
  ( 
  267' 
  ) 
  

  

  