﻿DR 
  GEORGE 
  WILSON 
  ON 
  NEW 
  PROCESSES 
  FOR 
  FLUORINE, 
  &c. 
  487 
  

  

  hydrochloric 
  acid 
  and 
  water 
  ; 
  the 
  product 
  of 
  distillation 
  was 
  tested 
  by 
  the 
  less 
  

   perfect 
  potassium 
  -process 
  ; 
  and 
  the 
  lines 
  etched 
  by 
  the 
  hydrofluoric 
  acid 
  were 
  

   drawn 
  too 
  fine. 
  Experience 
  has 
  taught 
  my 
  assistants 
  that 
  the 
  wax 
  should 
  be 
  

   spread 
  thin, 
  and 
  the 
  lines 
  through 
  it 
  be 
  made 
  with 
  a 
  broad 
  point, 
  if 
  a 
  distinct 
  

   etching 
  is 
  to 
  be 
  obtained. 
  But, 
  withal, 
  the 
  results 
  with 
  coal-ashes 
  are 
  sufficiently 
  

   marked. 
  

  

  I 
  have 
  further 
  tested 
  the 
  sufficiency 
  of 
  the 
  ammonia 
  process 
  in 
  the 
  following 
  

   stringent 
  way. 
  A 
  fossil 
  bone 
  from 
  the 
  Himalayas, 
  which 
  I 
  had 
  already 
  ascer- 
  

   tained 
  to 
  contain 
  a 
  fluoride, 
  and 
  which 
  was 
  full 
  of 
  crystals 
  of 
  carbonate 
  of 
  lime, 
  

   was 
  reduced 
  to 
  powder, 
  and 
  mixed 
  with 
  powdered 
  glass 
  so 
  as 
  to 
  add 
  to 
  it 
  excess 
  

   of 
  silica. 
  It 
  was 
  then 
  subjected 
  to 
  the 
  ammonia 
  process, 
  and 
  has 
  yielded 
  an 
  

   etching 
  as 
  deep 
  as 
  the 
  purest 
  fluorspar 
  could 
  have 
  given 
  with 
  oil 
  of 
  vitriol. 
  

  

  The 
  result 
  is 
  so 
  marked, 
  that 
  I 
  should 
  recommend 
  the 
  deliberate 
  addition 
  of 
  

   silica 
  to 
  bodies 
  suspected 
  to 
  contain 
  fluorine, 
  as 
  a 
  provision 
  for 
  permitting 
  such 
  

   substances 
  to 
  be 
  analysed 
  in 
  glass 
  vessels, 
  in 
  which 
  the 
  largest 
  quantities 
  may 
  be 
  

   subjected 
  to 
  examination 
  without 
  risk 
  of 
  missing 
  the 
  element 
  in 
  search, 
  or 
  per- 
  

   mitting 
  it 
  to 
  escape. 
  

  

  Five 
  points 
  call 
  for 
  further 
  notice. 
  

  

  1st, 
  When 
  a 
  silicated 
  fluoride, 
  as 
  I 
  may, 
  for 
  the 
  sake 
  of 
  brevity, 
  call 
  it, 
  is 
  distilled 
  

   with 
  oil 
  of 
  vitriol, 
  the 
  whole 
  of 
  the 
  fluoride 
  of 
  silicon 
  comes 
  away 
  as 
  gas, 
  as 
  soon 
  

   as 
  the 
  oil 
  of 
  vitriol 
  has 
  reached 
  its 
  boiling-point. 
  It 
  is 
  not 
  necessary, 
  accordingly, 
  

   to 
  subject 
  a 
  body 
  supposed 
  to 
  contain 
  fluorine 
  to 
  any 
  lengthened 
  ebullition 
  ; 
  and, 
  

   in 
  the 
  case 
  of 
  plant-ashes, 
  it 
  is 
  desirable 
  to 
  arrest 
  the 
  boiling 
  as 
  soon 
  as 
  all 
  the 
  

   fluorine 
  has 
  been 
  evolved, 
  for 
  protracted 
  ebullition 
  only 
  occasions 
  evolution 
  of 
  

   sulphurous 
  acid. 
  Besides 
  the 
  ultimate 
  glass-etching, 
  the 
  escape 
  of 
  fluorine 
  is 
  

   rendered 
  manifest 
  by 
  the 
  appearance 
  of 
  a 
  white 
  gelatinous 
  body 
  in 
  the 
  water, 
  

   through 
  which 
  the 
  gas 
  evolved 
  (Si 
  F 
  3 
  ) 
  is 
  passed 
  ; 
  and 
  by 
  the 
  production 
  of 
  a 
  

   gelatinous, 
  flocculent 
  precipitate, 
  when 
  the 
  solution 
  of 
  this 
  gas 
  is 
  neutralised 
  with 
  

   potass. 
  The 
  coal-ashes 
  gave 
  all 
  those 
  results. 
  

  

  2d, 
  It 
  appears 
  exceedingly 
  probable, 
  that 
  much 
  of 
  the 
  silica 
  occurring 
  in 
  the 
  

   forms 
  of 
  quartz, 
  chalcedony, 
  opal, 
  sinter, 
  and 
  the 
  like, 
  which 
  is 
  generally 
  sup- 
  

   posed 
  to 
  have 
  been 
  deposited 
  from 
  aqueous 
  or 
  alkaline 
  solution, 
  has 
  owed 
  its 
  origin 
  

   to 
  the 
  decomposition 
  of 
  fluoride 
  of 
  silicon 
  by 
  water, 
  or 
  has 
  otherwise 
  been 
  related 
  

   to 
  fluorine 
  as 
  its 
  solvent 
  or 
  transferring 
  agent. 
  This, 
  or 
  rather 
  the 
  less 
  precise 
  

   notion 
  of 
  fluorine 
  conveying 
  silica, 
  has 
  been 
  suggested 
  by 
  my 
  friend 
  Mr 
  A. 
  Bry- 
  

   son, 
  and 
  by 
  Dr 
  H. 
  Buchanan, 
  E.I.C.S. 
  

  

  3d, 
  The 
  occurrence 
  of 
  fluorspar 
  in 
  drusy 
  cavities 
  in 
  greenstone, 
  along 
  with 
  

   silica, 
  as 
  in 
  the 
  specimens 
  obtained 
  from 
  Bishopton, 
  on 
  the 
  Clyde 
  ; 
  the 
  similar 
  

   occurrence 
  of 
  apophyllite 
  in 
  the 
  cavities 
  of 
  trap 
  ; 
  the 
  association 
  of 
  topaz, 
  pyc- 
  

   nite, 
  lepidolite, 
  and 
  most 
  of 
  the 
  other 
  compound 
  fluorides, 
  with 
  granite, 
  gneiss, 
  

  

  vol 
  xx. 
  part 
  hi. 
  b' 
  p 
  

  

  