﻿ACADEMY 
  OF 
  SCIENCES. 
  69 
  

  

  the 
  large 
  scale 
  this 
  is, 
  of 
  course, 
  not 
  feasible. 
  In 
  the 
  third 
  place, 
  the 
  clay 
  

   mixed 
  with 
  the 
  mineral, 
  and 
  the 
  carbonate 
  of 
  lime 
  formed 
  by 
  the 
  soda, 
  make 
  the 
  

   residue 
  extremely 
  bulky. 
  It 
  takes 
  a 
  long 
  time 
  to 
  make 
  it 
  settle 
  into 
  a 
  pulp 
  of 
  

   some 
  reasonable 
  thickness 
  ; 
  therefore 
  several 
  washings 
  are 
  required 
  to 
  wash 
  the 
  

   absorbed 
  borax-solution 
  out, 
  thus 
  yielding 
  weak 
  solutions 
  which 
  have 
  to 
  be 
  

   ■worked 
  up 
  and 
  concentrated. 
  

  

  In 
  view 
  of 
  these 
  facts 
  I 
  thought 
  it 
  advisable 
  to 
  devise 
  a 
  better 
  process 
  than 
  

   the 
  one 
  described. 
  

  

  My 
  process 
  is 
  based 
  upon 
  the 
  volatilization 
  of 
  boracic 
  acid 
  by 
  water 
  vapors; 
  

   a 
  fact 
  which 
  nature 
  itself 
  proves, 
  by 
  furnishing 
  in 
  that 
  way 
  all 
  the 
  boracic 
  acid 
  

   manufactured 
  in 
  Tuscany. 
  But 
  by 
  my 
  own 
  experiments 
  I 
  discovered 
  that 
  that 
  

   volatilization 
  can 
  be 
  made 
  complete, 
  that 
  is, 
  that 
  a 
  given 
  quantity 
  of 
  boracic 
  

   acid 
  can 
  be 
  completely 
  volatilized 
  by 
  steam 
  alone. 
  

  

  The 
  plainest 
  experiment 
  which 
  laid 
  the 
  foundation 
  to 
  my 
  process 
  is 
  this 
  : 
  To 
  

   melt 
  in 
  a 
  platinum 
  crucible 
  some 
  boracic 
  acid 
  into 
  a 
  glass, 
  weigh 
  the 
  crucible 
  

   with 
  contents, 
  and 
  conduct 
  steam 
  by 
  a 
  brass 
  tube 
  into 
  the 
  crucible 
  while 
  the 
  

   latter 
  is 
  heated 
  to 
  redness. 
  By 
  weighing 
  from 
  time 
  to 
  time, 
  the 
  progress 
  of 
  vol- 
  

   atilization 
  may 
  be 
  observed. 
  After 
  two 
  hours 
  continuing 
  the 
  experiment, 
  more 
  

   or 
  less, 
  the 
  crucible 
  will 
  be 
  found 
  entirely 
  empty. 
  Other 
  experiments 
  by 
  which 
  

   I 
  suspended 
  a 
  weighed 
  platinum 
  wire, 
  on 
  to 
  which 
  a 
  pearl 
  of 
  boracic 
  acid 
  was 
  

   molten, 
  in 
  an 
  iron 
  gas-pipe, 
  and 
  conducted 
  steam 
  of 
  different 
  temperature 
  through 
  

   that 
  apparatus, 
  showed 
  that 
  the 
  speed 
  of 
  the 
  volatilization 
  is 
  entirely 
  depending 
  

   on 
  the 
  temperature 
  of 
  the 
  steam. 
  Steam 
  of 
  212° 
  F., 
  is 
  not 
  capable 
  of 
  removing 
  

   more 
  than 
  traces, 
  unless 
  the 
  reaction 
  is 
  allowed 
  to 
  continue 
  for 
  a 
  very 
  long 
  time. 
  

   If 
  the 
  gas 
  pipe 
  surrounding 
  the 
  boracic 
  acid 
  pearl 
  is 
  however, 
  heated 
  to 
  redness, 
  

   the 
  volatilization 
  is 
  most 
  rapid. 
  

  

  The 
  rather 
  surprising 
  fact 
  that 
  the 
  steam 
  of 
  212° 
  F. 
  has 
  so 
  little 
  power 
  for 
  

   the 
  purpose, 
  caused 
  me 
  to 
  experiment 
  on 
  some 
  statements 
  made 
  by 
  Henry 
  Rose, 
  

   the 
  celebrated 
  chemist 
  to 
  whom 
  we 
  are 
  mostly 
  indebted 
  for 
  our 
  knowledge 
  of 
  

   the 
  element 
  Boron 
  and 
  its 
  combinations. 
  Rose 
  states 
  that 
  it 
  is 
  not 
  possible 
  to 
  

   concentrate 
  a 
  solution 
  containing 
  free 
  boracic 
  acid 
  without 
  loss 
  of 
  substance. 
  

   I 
  found 
  this 
  correct 
  when 
  the 
  solution 
  is 
  evaporated 
  in 
  an 
  open 
  dish, 
  but 
  not 
  so 
  

   when 
  the 
  concentration 
  takes 
  place 
  in 
  a 
  glass 
  flask. 
  On 
  concentrating 
  a 
  quite 
  

   concentrated 
  solution 
  of 
  boracic 
  acid 
  in 
  a 
  glass 
  flask 
  over 
  a 
  moderate 
  fire, 
  I 
  

   never 
  could 
  condense 
  more 
  boracic 
  acid 
  than 
  the 
  mechanical 
  carrying 
  off" 
  by 
  the 
  

   vapors 
  would 
  account 
  for, 
  that 
  is 
  a 
  trace. 
  In 
  an 
  open 
  dish, 
  however, 
  in 
  the 
  

   progress 
  of 
  concentration, 
  a 
  ring 
  of 
  boracic 
  acid 
  separated 
  on 
  the 
  dish, 
  which 
  

   boracic 
  acid 
  is 
  heated 
  much 
  more 
  than 
  the 
  solution 
  and 
  is 
  exposed 
  to 
  the 
  action 
  

   of 
  the 
  steam 
  rising 
  from 
  the 
  liquid. 
  In 
  that 
  case 
  a 
  volatilization 
  takes 
  place. 
  

  

  Having 
  found 
  out 
  that 
  superheated 
  steam 
  is 
  much 
  more 
  powerful 
  in 
  carrying 
  

   ofif 
  boracic 
  acid 
  than 
  steam 
  of 
  21 
  '.^o 
  F., 
  it 
  was 
  easy 
  to 
  conclude 
  that 
  the 
  con- 
  

   densation 
  of 
  the 
  volatilized 
  boracic 
  acid 
  could 
  not 
  present 
  great 
  difficulties. 
  The 
  

   boracic 
  acid 
  volatilized 
  in 
  the 
  apparatus 
  described 
  before, 
  that 
  is, 
  in 
  a 
  heated 
  

   iron 
  pipe, 
  was 
  found 
  condensed 
  in 
  the 
  colder 
  portion 
  of 
  the 
  pipe. 
  By 
  regulating 
  

   the 
  length 
  and 
  temperature 
  of 
  the 
  pipe, 
  the 
  fact 
  resulted 
  that 
  the 
  steam 
  could 
  

   be 
  deprived 
  nearly 
  entirely 
  of 
  its 
  percentage 
  in 
  boracic 
  acid. 
  

  

  