﻿480 
  DR 
  GEORGE 
  WILSON 
  ON 
  NEW 
  PROCESSES 
  FOR 
  FLUORINE, 
  &C. 
  

  

  I 
  treated 
  the 
  powdered 
  pieces 
  of 
  rock 
  with 
  hydrochloric 
  acid, 
  and 
  washed 
  them 
  

   with 
  water, 
  then 
  dried 
  them, 
  and 
  heated 
  them 
  with 
  oil 
  of 
  vitriol. 
  The 
  prelimi- 
  

   nary 
  treatment, 
  however, 
  risked, 
  and 
  I 
  have 
  no 
  doubt 
  occasioned, 
  the 
  loss 
  of 
  the 
  

   fluorides 
  present 
  in 
  the 
  mineral, 
  which 
  were 
  soluble 
  in 
  water 
  or 
  in 
  hydrochloric 
  

   acid 
  ; 
  and 
  latterly 
  I 
  abandoned 
  this 
  process. 
  I 
  refer 
  to 
  it 
  here 
  only 
  because 
  it 
  ex- 
  

   plains 
  certain 
  of 
  the 
  less 
  perfect 
  etchings 
  which 
  are 
  exhibited. 
  

  

  In 
  later 
  trials, 
  a 
  simpler 
  and 
  more 
  satisfactory 
  process 
  has 
  been 
  put 
  in 
  prac- 
  

   tice. 
  The 
  powdered 
  rock 
  has 
  been 
  added 
  to 
  oil 
  of 
  vitriol 
  in 
  the 
  cold, 
  in 
  small 
  

   quantities 
  at 
  a 
  time, 
  so 
  as 
  to 
  prevent 
  any 
  great 
  rise 
  in 
  temperature. 
  So 
  long 
  as 
  

   the 
  heat 
  evolved 
  is 
  not 
  considerable, 
  there 
  is 
  no 
  risk 
  of 
  fluorine 
  escaping, 
  either 
  as 
  

   hydrofluoric 
  acid 
  or 
  as 
  fluoride 
  of 
  silicon, 
  whilst 
  any 
  chlorides 
  or 
  carbonates 
  pre- 
  

   sent 
  are 
  decomposed, 
  and 
  the 
  hydrochloric 
  and 
  carbonic 
  acids 
  evolved, 
  are 
  carried 
  

   away, 
  before 
  their 
  escape 
  can 
  interfere 
  with 
  the 
  evolution 
  of 
  fluorine. 
  When 
  the 
  

   oil 
  of 
  vitriol 
  is 
  afterwards 
  raised 
  to 
  its 
  boiling-point, 
  the 
  fluoride 
  of 
  silicon 
  is 
  

   liberated, 
  and 
  little 
  difficulty 
  attends 
  its 
  collection 
  and 
  identification. 
  

  

  The 
  ashes 
  of 
  plants 
  are 
  somewhat 
  less 
  easily 
  examined. 
  They 
  almost 
  inva- 
  

   riably 
  contain 
  charcoal, 
  which 
  occasions 
  the 
  evolution 
  of 
  sulphurous 
  acid 
  with 
  

   hot 
  oil 
  of 
  vitriol. 
  Sulphurous 
  acid, 
  however, 
  does 
  not 
  very 
  materially 
  interfere 
  

   with 
  the 
  detection 
  of 
  fluorine, 
  as 
  it 
  can 
  be 
  expelled 
  by 
  heating 
  the 
  distillate 
  before 
  

   adding 
  ammonia, 
  which 
  is 
  the 
  process 
  I 
  have 
  hitherto 
  generally 
  followed. 
  It 
  may 
  

   also 
  be 
  converted 
  into 
  sulphuric 
  acid 
  by 
  the 
  cautious 
  addition 
  of 
  nitric 
  acid, 
  and 
  

   then 
  its 
  presence 
  is 
  quite 
  immaterial. 
  But 
  in 
  several 
  quite 
  successful 
  trials 
  no 
  

   steps 
  were 
  adopted 
  to 
  separate 
  the 
  sulphurous 
  acid. 
  

  

  The 
  specimen 
  laid 
  upon 
  the 
  table, 
  of 
  glass 
  etched 
  by 
  fluorine 
  from 
  barley- 
  

   straw, 
  will 
  illustrate 
  the 
  applicability 
  of 
  the 
  process 
  to 
  plant-ashes 
  largely 
  charged 
  

   with 
  silica, 
  and 
  which 
  yielded, 
  with 
  oil 
  of 
  vitriol, 
  carbonic 
  and 
  hydrochloric 
  acid, 
  

   besides 
  much 
  sulphurous 
  acid. 
  

  

  The 
  glass 
  etched 
  by 
  the 
  fluorine 
  of 
  charcoal-ashes 
  is 
  still 
  more 
  deeply 
  cor- 
  

   roded, 
  although 
  they 
  were 
  subjected 
  to 
  no 
  preliminary 
  process 
  to 
  remove 
  the^vola- 
  

   tile 
  acids 
  which 
  they 
  contained, 
  or 
  to 
  set 
  free 
  or 
  separate 
  the 
  sulphurous 
  acid 
  

   which 
  they 
  yielded. 
  

  

  In 
  truth, 
  the 
  ammonia 
  process 
  has 
  succeeded 
  with 
  every 
  substance 
  upon 
  

   which 
  I 
  have 
  tried 
  it. 
  The 
  worst 
  result 
  has 
  been 
  with 
  the 
  ashes 
  of 
  hay, 
  but 
  they 
  

   had 
  been 
  washed 
  with 
  water 
  and 
  hydrochloric 
  acid 
  to 
  remove 
  chlorides 
  and 
  car- 
  

   bonates 
  ; 
  and 
  in 
  former 
  papers 
  I 
  have 
  shewn 
  that 
  such 
  washings 
  remove 
  fluorides. 
  

   Notwithstanding 
  this, 
  the 
  evidence 
  of 
  the 
  presence 
  of 
  fluorine 
  in 
  hay, 
  afforded 
  by 
  

   the 
  specimen, 
  is 
  such 
  as 
  has 
  not 
  hitherto 
  (so 
  far 
  as 
  I 
  am 
  aware) 
  been 
  afforded 
  by 
  

   any 
  analyst, 
  and 
  the 
  omission 
  of 
  the 
  washings 
  will, 
  I 
  have 
  no 
  doubt, 
  yield 
  a 
  still 
  

   more 
  satisfactory 
  result 
  on 
  a 
  repetition 
  of 
  the 
  analysis. 
  The 
  same 
  remark 
  applies 
  

   to 
  coal-ashes, 
  by 
  the 
  fluorine 
  of 
  which 
  I 
  have 
  only 
  one 
  etching 
  to 
  shew. 
  It 
  is 
  not 
  

   a 
  favourable 
  specimen 
  ; 
  the 
  ashes 
  were 
  washed 
  with 
  a 
  considerable 
  volume 
  of 
  

  

  