﻿260 
  ANNUAL 
  EEPORT 
  SMITHSONIAN 
  INSTITUTION, 
  192 
  9 
  

  

  cheaply 
  obtained, 
  thanks 
  to 
  synthetic 
  chemistry. 
  Except 
  in 
  the 
  case 
  

   of 
  the 
  most 
  expensive, 
  they 
  contain 
  no 
  perfume 
  material 
  obtained 
  

   from 
  the 
  violet 
  itself, 
  except, 
  perhaps, 
  a 
  small 
  proportion 
  of 
  the 
  extract 
  

   of 
  violet 
  leaves, 
  added 
  to 
  give 
  freshness 
  to 
  the 
  odor. 
  

  

  Prior 
  to 
  the 
  discovery 
  of 
  "synthetic 
  violet," 
  the 
  preparation 
  of 
  sat- 
  

   isfactory 
  violet 
  perfumes 
  was 
  a 
  very 
  difficult 
  proposition, 
  owing 
  to 
  the 
  

   fact 
  that 
  the 
  flowers 
  contain 
  only 
  microscopic 
  amounts 
  of 
  perfume 
  

   material. 
  The 
  odor 
  of 
  the 
  violet 
  is 
  a 
  rare 
  one 
  in 
  nature, 
  orris-root 
  and 
  

   cassie 
  {Acacia 
  farnesiana) 
  being 
  about 
  the 
  only 
  available 
  natural 
  

   sources 
  from 
  which 
  a 
  tolerable 
  substitute 
  for 
  the 
  violet 
  can 
  be 
  ob- 
  

   tained. 
  

  

  An 
  investigation 
  by 
  Tiemann 
  and 
  Kriiger 
  of 
  the 
  constitution 
  of 
  the 
  

   oil 
  of 
  orris-root 
  revealed 
  the 
  fact 
  that 
  its 
  odor 
  is 
  almost 
  entirely 
  due 
  to 
  

   a 
  ketone, 
  which 
  was 
  christened 
  ''irone." 
  These 
  chemists 
  prepared 
  an 
  

   isomer 
  of 
  this 
  substance 
  by 
  condensing 
  citral 
  with 
  acetone. 
  By 
  heat- 
  

   ing 
  this 
  substance 
  with 
  dilute 
  sulphuric 
  acid 
  in 
  the 
  presence 
  of 
  a 
  little 
  

   glycerol, 
  it 
  was 
  hoped 
  that 
  an 
  isomeric 
  change 
  would 
  take 
  place 
  result- 
  

   ing 
  in 
  the 
  formation 
  of 
  irone. 
  An 
  isomeric 
  change 
  did 
  take 
  place; 
  but 
  

   the 
  product 
  was 
  not 
  irone, 
  since 
  synthesized 
  by 
  a 
  different 
  process. 
  It 
  

   was 
  a 
  substance, 
  to 
  be 
  named 
  "ionone," 
  with 
  an 
  intense 
  odor 
  of 
  violets, 
  

   much 
  nearer 
  to 
  that 
  of 
  the 
  flower 
  than 
  the 
  anticipated 
  irone. 
  

  

  Nowadays, 
  ionone 
  is 
  the 
  basic 
  material 
  of 
  all 
  violet 
  perfumes, 
  and 
  is 
  

   one 
  of 
  the 
  most 
  important 
  synthetic 
  products 
  in 
  the 
  art 
  of 
  perfumery. 
  

   Actually 
  it 
  is 
  not 
  a 
  chemical 
  individual, 
  but 
  a 
  mixture 
  of 
  two 
  isomers. 
  

   These 
  can 
  be 
  separated. 
  Their 
  odors 
  are 
  not 
  identical, 
  and 
  each 
  has 
  

   its 
  several 
  uses 
  in 
  the 
  manufacture 
  of 
  various 
  types 
  of 
  violet 
  scents. 
  

  

  Another 
  very 
  important 
  synthetic 
  product 
  employed 
  in 
  the 
  confec- 
  

   tion 
  of 
  these 
  and 
  other 
  perfumes 
  is 
  methyl 
  heptine 
  carbonate, 
  which, 
  

   used 
  in 
  minute 
  quantities, 
  gives 
  that 
  note 
  of 
  •'freshness" 
  so 
  character- 
  

   istic 
  of 
  the 
  fragrance 
  of 
  sweet 
  violets. 
  

  

  The 
  list 
  of 
  synthetic 
  materials 
  used 
  in 
  perfumery 
  could 
  be 
  extended 
  

   indefinitely. 
  But 
  enough 
  has 
  been 
  said 
  to 
  indicate 
  how 
  important 
  a 
  

   branch 
  of 
  chemistry 
  the 
  preparation 
  of 
  synthetic 
  perfumes 
  is. 
  The 
  

   average 
  Englishman, 
  perhaps, 
  is 
  apt 
  to 
  think 
  of 
  perfumery 
  as 
  a 
  rather 
  

   frivolous 
  subject. 
  Actually, 
  not 
  only 
  great 
  technical 
  skill 
  and 
  artistic 
  

   sensibility 
  are 
  required 
  for 
  the 
  confection 
  of 
  a 
  fine 
  perfume, 
  but 
  often 
  

   years 
  of 
  scientific 
  research 
  have 
  gone 
  to 
  the 
  making 
  of 
  it. 
  Every 
  year 
  

   brings 
  forth 
  new 
  discoveries, 
  more 
  and 
  more 
  new 
  substances, 
  syntheti- 
  

   cally 
  prepared, 
  being 
  added 
  to 
  the 
  number 
  of 
  materials 
  available 
  for 
  

   use 
  by 
  the 
  perfume 
  artist. 
  As 
  the 
  mass 
  of 
  material 
  accumulates, 
  it 
  

   may 
  be 
  hoped 
  that 
  we 
  approach 
  nearer 
  to 
  the 
  solution 
  of 
  the 
  problem 
  

   of 
  the 
  relation 
  between 
  odor 
  and 
  chemical 
  constitution, 
  and 
  to 
  that 
  

   of 
  the 
  even 
  more 
  inscrutable 
  puzzle 
  of 
  why 
  certain 
  classes 
  of 
  odors 
  are 
  

   pleasant, 
  others 
  unpleasant, 
  to 
  the 
  olfactory 
  nerves 
  of 
  human 
  beings. 
  

  

  