﻿SYNTHETIC 
  PERFUMES 
  

  

  By 
  H. 
  Stanley 
  Redgrove. 
  B.Sc, 
  A. 
  I. 
  C. 
  

  

  The 
  science 
  of 
  chemistry 
  has 
  invaded 
  almost 
  every 
  department 
  

   of 
  dail}^ 
  life, 
  without 
  the 
  man 
  in 
  the 
  street 
  being 
  at 
  all 
  cognizant 
  

   of 
  the 
  debt 
  he 
  owes 
  to 
  it. 
  Nor 
  is 
  it 
  realized 
  how 
  many 
  common 
  

   domestic 
  operations, 
  like 
  cooking 
  a 
  dinner, 
  for 
  example, 
  really 
  

   consist 
  in 
  causing 
  a 
  number 
  of 
  more 
  or 
  less 
  complicated 
  chemical 
  

   reactions 
  to 
  take 
  place 
  in 
  the 
  materials 
  employed. 
  By 
  the 
  man 
  

   in 
  the 
  street 
  and 
  the 
  housewife 
  in 
  the 
  kitchen, 
  "chemicals" 
  are 
  

   thought 
  to 
  be 
  substances 
  of 
  a 
  nature 
  quite 
  distinct 
  from 
  the 
  things 
  

   they 
  daily 
  handle 
  and 
  to 
  be 
  chiefly 
  characterized 
  by 
  the 
  possession 
  

   of 
  a 
  "nasty 
  smell." 
  

  

  There 
  is, 
  indeed, 
  an 
  important 
  difference 
  between 
  the 
  "substances" 
  

   of 
  the 
  chemist 
  and 
  the 
  raw 
  products 
  of 
  nature, 
  whether 
  of 
  animal, 
  

   vegetable 
  or 
  mineral 
  origin; 
  and 
  it 
  is 
  very 
  germane 
  to 
  the 
  present 
  

   study 
  to 
  ask. 
  Wherein 
  does 
  this 
  difference 
  lie? 
  The 
  answer 
  is 
  that 
  

   chemical 
  substances 
  are 
  "pure." 
  It 
  is 
  true 
  that 
  when 
  we 
  seek 
  to 
  

   define 
  what 
  is 
  meant 
  by 
  "purity" 
  certain 
  philosophical 
  difficulties 
  

   crop 
  up, 
  as 
  Ostwald 
  pointed 
  out 
  many 
  years 
  ago, 
  and 
  a 
  long 
  dis- 
  

   cussion 
  could 
  be 
  entered 
  into 
  on 
  the 
  question, 
  for 
  example, 
  whether 
  

   solutions 
  are 
  chemical 
  compounds 
  or 
  merely 
  mixtures. 
  For 
  prac- 
  

   tical 
  purposes, 
  however, 
  "purity" 
  is 
  well 
  understood 
  to 
  denote 
  

   obedience 
  to 
  the 
  stoichiometric 
  laws. 
  A 
  pure 
  substance, 
  moreover, 
  

   possesses 
  certain 
  peculiar 
  physical 
  properties, 
  such 
  as 
  a 
  constant 
  

   boiling 
  point. 
  

  

  No 
  doubt 
  very 
  few 
  chemical 
  substances 
  ordinarily 
  sold 
  as 
  pure 
  

   are 
  realy 
  pure, 
  it 
  being, 
  indeed, 
  extraordinarily 
  difficult 
  to 
  obtain 
  

   an 
  absolutely 
  pure 
  substance. 
  But 
  chemistry 
  — 
  shall 
  I 
  say? 
  — 
  strives 
  

   after 
  purity 
  and 
  attains 
  very 
  nearly 
  to 
  it. 
  

  

  On 
  the 
  other* 
  hand, 
  nature's 
  products 
  are 
  never 
  pure; 
  they 
  are 
  

   invariably 
  mixtures, 
  and 
  usually 
  very 
  complex 
  ones, 
  taxing 
  the 
  skill 
  

   of 
  the 
  analytical 
  chemist 
  to 
  unravel 
  the 
  riddle 
  of 
  their 
  composition. 
  

  

  The 
  application 
  of 
  the 
  term 
  "impure" 
  to 
  the 
  products 
  of 
  nature, 
  

   it 
  will 
  be 
  understood, 
  carries 
  with 
  it 
  no 
  implication 
  of 
  inferiority, 
  

  

  ' 
  Repriited 
  by 
  permission 
  from 
  Science 
  Progress, 
  July, 
  1929. 
  

  

  253 
  

  

  