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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  Velon, 
  and 
  synthetic 
  rubber 
  yarns 
  belong 
  to 
  this 
  group. 
  I 
  should 
  like 
  

   to 
  suggest 
  the 
  words 
  "synthesized 
  fibers" 
  for 
  this 
  group, 
  instead 
  of 
  

   synthetic 
  fibers, 
  although 
  the 
  latter 
  could 
  be 
  used 
  here 
  justifiably. 
  

  

  This 
  second 
  main 
  group 
  I 
  should 
  like 
  to 
  subdivide, 
  for 
  the 
  present 
  at 
  

   least, 
  first, 
  into 
  the 
  polyamids, 
  which 
  cover 
  Du 
  Pont's 
  nylon 
  filaments, 
  

   staple 
  fiber 
  and 
  bristles; 
  second 
  into 
  the 
  polyesters, 
  which 
  cover 
  

   Vinyon 
  filament 
  and 
  Vinyon 
  E, 
  the 
  new 
  elastic 
  yarn 
  ; 
  third, 
  into 
  the 
  

   thermoplastic 
  resins, 
  under 
  which 
  would 
  come 
  saran, 
  Velon, 
  Permalon, 
  

   and 
  others; 
  fourth 
  and 
  last, 
  the 
  hydrocarbons, 
  which 
  are 
  to 
  include 
  

   all 
  new 
  synthetic 
  rubber 
  filaments, 
  threads, 
  and 
  cords 
  in 
  full 
  develop- 
  

   ment 
  now. 
  

  

  This 
  classification 
  separates 
  the 
  main 
  products, 
  and 
  subordinates 
  

   none. 
  I 
  recommend 
  it 
  to 
  you 
  for 
  consideration. 
  

  

  