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  Hobbs 
  — 
  Crystal 
  Form 
  of 
  Borneol 
  and 
  Isoborneol. 
  449 
  

  

  Art. 
  XXXYII. 
  — 
  On 
  the 
  Crystal 
  Form 
  of 
  Bomeol 
  and 
  

   Isoborneol; 
  by 
  Wm. 
  H. 
  Hobbs. 
  

  

  In 
  a 
  recent 
  paper 
  by 
  Bertram 
  and 
  Walbaum* 
  on 
  an 
  isomer 
  

   of 
  borneol 
  (C 
  10 
  H 
  18 
  O) 
  which 
  they 
  have 
  called 
  isoborneol, 
  Traube 
  

   has 
  described 
  both 
  this 
  substance 
  and 
  borneol 
  from 
  a 
  crystallo- 
  

   graphical 
  standpoint. 
  The 
  borneol 
  examined 
  was 
  obtained 
  by 
  

   reduction 
  of 
  camphor, 
  had 
  a 
  melting 
  point 
  of 
  206°-207°, 
  and 
  

   was 
  dextro-rotatory. 
  The 
  symmetry 
  of 
  both 
  borneol 
  and 
  isobor- 
  

   neol 
  as 
  determined 
  by 
  Traube 
  is 
  hexagonal, 
  the 
  combination 
  

   in 
  each 
  case 
  being 
  the 
  basal 
  pinacoid 
  with 
  the 
  pyramid 
  and 
  

   prism. 
  The 
  chief 
  differences 
  between 
  the 
  two 
  substances 
  he 
  

   finds 
  to 
  be 
  the 
  greater 
  double 
  refraction 
  of 
  isoborneol, 
  and 
  its 
  

   positive 
  optical 
  character, 
  borneol 
  being 
  optically 
  negative. 
  

   The 
  axial 
  ratio 
  of 
  borneol 
  he 
  determined 
  to 
  be 
  exactly 
  double 
  

   that 
  of 
  isoborneol. 
  

  

  Three 
  samples 
  of 
  the 
  alcohol 
  C 
  10 
  II 
  18 
  O 
  were 
  given 
  me 
  for 
  

   examination 
  to 
  determine 
  whether 
  they 
  are 
  borneol 
  or 
  isobor- 
  

   neol. 
  They 
  were 
  prepared 
  in 
  the 
  School 
  of 
  Pharmacy 
  of 
  the 
  

   University 
  of 
  Wisconsin 
  by 
  Mr. 
  Carl 
  Gr. 
  Hunkel, 
  whose 
  study 
  

   of 
  them 
  will 
  be 
  published 
  in 
  the 
  P 
  harmaceutisohe 
  Rundschau. 
  

   The 
  samples 
  were 
  prepared, 
  one 
  from 
  the 
  oil 
  of 
  black 
  spruce 
  

   {Picea 
  nigra) 
  in 
  which 
  the 
  alcohol 
  is 
  contained 
  as 
  acetic 
  ester, 
  

   a 
  second 
  from 
  the 
  oil 
  of 
  the 
  fir 
  balsam 
  {Abies 
  balsamia), 
  and 
  

   the 
  third 
  from 
  the 
  oil 
  of 
  turpentine 
  in 
  benzine. 
  The 
  crystals 
  

   in 
  all 
  these 
  samples 
  are 
  larger 
  and 
  more 
  highly 
  modified 
  than 
  

   those 
  described 
  by 
  Traube, 
  and 
  their 
  examination 
  has 
  brought 
  

   out 
  new 
  facts 
  concerning 
  their 
  crystallography 
  and 
  physical 
  

   properties. 
  The 
  surest 
  basis 
  of 
  comparison 
  with 
  the 
  crystals 
  

   described 
  by 
  Traube 
  has 
  been 
  the 
  degree 
  of 
  double 
  refraction. 
  

   The 
  crystals 
  obtained 
  from 
  Picea 
  nigra 
  and 
  Abies 
  balsamia 
  

   in 
  this 
  respect 
  correspond 
  exactly 
  with 
  the 
  borneol 
  of 
  Traube's 
  

   study. 
  The 
  crystals 
  in 
  the 
  sample 
  obtained 
  from 
  turpentine, 
  

   on 
  the 
  other 
  hand, 
  correspond 
  with 
  his 
  isoborneol 
  so 
  far 
  as 
  the 
  

   degree 
  of 
  double 
  refraction 
  is 
  concerned, 
  but 
  they 
  are 
  always 
  

   optically 
  negative, 
  in 
  this 
  respect 
  agreeing 
  with 
  borneol. 
  It 
  is 
  

   therefore 
  not 
  certain 
  that 
  this 
  substance 
  is 
  identical 
  with 
  the 
  

   isoborneol 
  of 
  Bertram 
  and 
  Walbaum, 
  but 
  it 
  seems 
  best 
  from 
  

   all 
  the 
  facts 
  to 
  refer 
  to 
  it 
  for 
  the 
  present 
  as 
  isoborneol. 
  All 
  

   the 
  samples 
  examined 
  have 
  rhombohedral 
  symmetry. 
  This 
  is 
  

   clearly 
  shown 
  by 
  the 
  partial 
  occurrence 
  of 
  pyramids, 
  and 
  in 
  

   the 
  case 
  of 
  the 
  crystals 
  from 
  Picea 
  nigra 
  by 
  the 
  tri-symmetric 
  

   character 
  of 
  pittings 
  on 
  the 
  basal 
  pinacoid. 
  Of 
  the 
  nine 
  pyra- 
  

   midal 
  forms 
  which 
  have 
  been 
  made 
  out 
  on 
  the 
  two 
  substances 
  

  

  *Ueber 
  Isoborneol, 
  Journ. 
  f. 
  prakt. 
  Chemie, 
  vol. 
  xlix 
  (1894), 
  pp. 
  1-19. 
  

  

  