﻿MR. 
  F. 
  RUTLEY 
  ON 
  FULGURITES 
  FROM 
  MONTE 
  VISO. 
  63 
  

  

  these 
  specimens 
  to 
  be 
  made 
  in 
  the 
  Science 
  Schools 
  at 
  South 
  Ken- 
  

   sington, 
  and 
  Mr. 
  Chapman 
  has 
  been 
  most 
  successful 
  in 
  the 
  exceed- 
  

   ingly 
  delicate 
  and 
  difficult 
  operation 
  of 
  preparing 
  slices 
  of 
  the 
  rock 
  

   with 
  portions 
  of 
  the 
  fulgurite 
  -glass 
  adhering 
  to 
  the 
  surface. 
  

  

  Having 
  described 
  to 
  some 
  extent 
  the 
  nature 
  of 
  the 
  rock 
  itself, 
  

   these 
  vitreous 
  incrustations 
  will 
  now 
  claim 
  our 
  attention. 
  Before 
  

   the 
  sections 
  were 
  prepared, 
  a 
  few 
  small 
  pellets 
  of 
  fulgurite-glass 
  were 
  

   scraped 
  from 
  the 
  surface 
  of 
  one 
  of 
  the 
  specimens, 
  crushed, 
  and 
  ex- 
  

   amined 
  under 
  a 
  quarter-inch 
  objective. 
  Two 
  rod-like 
  microliths 
  

   (longulites) 
  were 
  first 
  observed 
  in 
  a 
  small 
  fragment 
  of 
  glass 
  which 
  

   was 
  picked 
  with 
  the 
  point 
  of 
  a 
  knife 
  from 
  one 
  of 
  the 
  surfaces, 
  either 
  

   of 
  fracture 
  or 
  rough 
  cleavage, 
  on 
  the 
  larger 
  specimen, 
  fig. 
  1, 
  PI. 
  III. 
  

   These 
  microliths 
  were, 
  when 
  first 
  seen, 
  situated 
  at 
  a 
  slight 
  distance 
  

   from 
  one 
  another 
  ; 
  but, 
  owing 
  to 
  the 
  viscidity 
  of 
  the 
  balsam 
  in 
  

   which 
  they 
  were 
  mounted, 
  it 
  was 
  found 
  that 
  after 
  an 
  hour 
  or 
  more 
  

   the 
  smaller 
  one 
  had 
  shifted 
  its 
  position, 
  so 
  as 
  to 
  come 
  in 
  contact 
  

   with 
  the 
  larger 
  microlith. 
  Evidently, 
  then, 
  one 
  of 
  these 
  rod-like 
  

   bodies 
  was 
  free 
  to 
  move, 
  and 
  was 
  not 
  imbedded 
  in 
  the 
  glass-fragment, 
  

   a 
  circumstance 
  which 
  necessarily 
  raised 
  the 
  question 
  whether 
  the 
  

   other 
  was 
  also 
  unattached. 
  

  

  Another 
  small 
  sample 
  was 
  consequently 
  taken, 
  also 
  from 
  a 
  frac- 
  

   tured 
  surface 
  of 
  the 
  rock, 
  and 
  crushed, 
  so 
  that 
  the 
  fragments 
  might 
  

   be 
  thin 
  enough 
  for 
  microscopic 
  examination. 
  Here, 
  again, 
  microliths 
  

   appeared, 
  not 
  only 
  on 
  or 
  in 
  the 
  fulgurite-glass, 
  but 
  also 
  in 
  consider- 
  

   able 
  numbers 
  in 
  the 
  fine 
  powder 
  which 
  resulted 
  from 
  the 
  crushing 
  of 
  

   the 
  fragments. 
  

  

  Thinking 
  it 
  might 
  be 
  possible 
  that 
  they 
  belonged 
  rather 
  to 
  the 
  

   rock 
  itself 
  than 
  to 
  the 
  actually 
  fused 
  rock-matter, 
  another 
  minute 
  

   pellet 
  of 
  fulgurite-glass 
  was 
  removed, 
  and, 
  on 
  examining 
  it 
  with 
  a 
  

   lens, 
  a 
  small 
  quantity 
  of 
  the 
  rock 
  was 
  found 
  adhering 
  as 
  a 
  film 
  to 
  

   the 
  surface 
  of 
  the 
  pellet 
  where 
  it 
  had 
  been 
  detached. 
  

  

  To 
  avoid 
  any 
  such 
  source 
  of 
  error, 
  a 
  very 
  small 
  blister 
  of 
  fulgurite- 
  

   glass 
  was 
  removed 
  from 
  the 
  interior 
  of 
  one 
  of 
  the 
  lightning-tubes 
  

   (a, 
  fig. 
  1, 
  PI. 
  III.), 
  where 
  the 
  lining 
  of 
  vesicular 
  glass 
  was 
  sufficiently 
  

   thick 
  to 
  insure 
  perfect 
  isolation 
  of 
  the 
  glass 
  from 
  the 
  rock. 
  This, 
  

   when 
  crushed 
  and 
  examined 
  under 
  a 
  power 
  of 
  about 
  250 
  diameters,, 
  

   showed 
  that 
  the 
  glass 
  is, 
  as 
  a 
  rule, 
  remarkably 
  pure, 
  but 
  that 
  not 
  only 
  

   gas-bubbles 
  but 
  globulites 
  occur 
  in 
  it, 
  in 
  places, 
  and 
  these 
  occasion- 
  

   ally 
  form 
  margarites 
  and 
  longulites, 
  some 
  of 
  the 
  rod-like 
  bodies 
  which 
  

   come 
  under 
  the 
  last 
  denomination 
  distinctly 
  exhibiting 
  double 
  

   refraction. 
  A 
  few 
  of 
  the 
  better-formed 
  examples 
  can 
  be 
  proved 
  to 
  

   lie 
  within 
  the 
  fulgurite-glass, 
  since 
  adjacent 
  globulites 
  can 
  be 
  

   brought 
  into 
  focus 
  both 
  above 
  and 
  below 
  them. 
  

  

  I 
  have 
  taken 
  especial 
  pains 
  to 
  verify 
  this 
  point, 
  since, 
  so 
  far 
  as 
  I 
  

   know, 
  this 
  is 
  the 
  first 
  instance 
  of 
  the 
  occurrence 
  of 
  crystallites 
  in 
  

   fulgurite-glass 
  which 
  has 
  hitherto 
  been 
  recorded. 
  In 
  these 
  speci- 
  

   mens 
  the 
  globulitic 
  and 
  longulitic 
  conditions 
  are 
  frequently 
  visible, 
  

   but 
  the 
  margaritic 
  stage 
  is 
  not 
  so 
  common. 
  Adopting 
  Vogelsang's 
  

   terminology, 
  all 
  of 
  these 
  bodies 
  would 
  be 
  included 
  under 
  the 
  name 
  

   of 
  crystallites. 
  A 
  longulite 
  and 
  some 
  globulites 
  are 
  shown 
  in 
  fig. 
  4 
  y 
  

  

  