282  Researches  on  Calamus  Oil.  {^L^SSE*" 
little  of  the  most  concentrated  sulphuric  acid,  to  which  is  added  a 
relatively  minute  portion  of  bichromate  of  potash.    The  mixture  is 
well  stirred  so  that  the  liberated  chromic  acid  may  be  uniformly  dis- 
tributed through  the  sulphuric  acid.  A  small  drop  of  the  liquid  under 
examination  is  placed  upon  the  acid  mixture,  which  immediately  gives 
a  brown  coloration  at  the  point  of  contact.    If  the  proportion  of 
phenol  is  larger  than  one  part  in  30,000  the  coloration  is  accompanied 
with  a  chocolate-brown  precipitate.    The  author  has  also  examined 
Landolt's  test,  which  consists  in  adding  to  the  suspected  solution 
bromine  water  in  slight  excess.    If  phenol  is  present  a  yellowish- 
white  precipitate  is  produced.    The  sensibility  of  this  reaction  ex- 
tends to  one  part  in  45,500.    As  Landolt  has  remarked,  precipitates 
more  or  less  similar,  are  produced  by  oxybenzoic  acid,  the  homologues 
of  phenic  acid,  anilin,  toluidin,  quinia,  quinidih,  cinchonia,  strychnia, 
narcotina  and  morphia.  The  author  considers  that  the  yellowish-white 
precipitate  may  be  rocognized  as  tribromo-phenol  by  the  following 
reactions  : — It  has  a  special  odor,  slightly  recalling  that  of  the  hy- 
dride of  salicyle.   It  is  insoluble  in  acids,  but  soluble  in  alkalies,  ether, 
and  absolute  alcohol.    A  very  small  quantity  of  water  completely 
separates  tribromo-phenol  from  its  alcoholic  solution.    If  carefully 
heated  on  platinum  foil  it  may  be  volatilized  unchanged  without  leav- 
ing a  residue.     But  if  the  heat  is  strong  the  compound  is  decom- 
posed and  burns  with  a  smoky  flame,  evolving  much  bromine,  and 
leaving  a  carbonaceous  residue.    A  portion  placed  in  a  porcelain 
capsule,  and  treated  with  sulphuric  acid  and  bichromate  of  potash, 
produces  a  chocolate-brown  color,  with  the  escape  of  bromine  vapors. 
If  the  bichromate  is  dissolved  in  water,  and  the  experiment  conducted 
in  a  glass  tube,  with  the  application  of  heat,  the  liquid  takes  a  fine 
green  color.    If  gently  heated  with  nitre  and  concentrated  sulphuric 
acid  it  forms  oily  drops  of  a  fine  red  color,  which  burn,  leaving  a  bulky 
carbonaceous  residue. —  Qhemical  News,  May  8,  from  Qaz.  Qhim.  ital. 
1874. 
RESEARCHES  ON  CALAMUS  OIL. 
By  A.  Kurbatow. 
When  this  oil  is  submitted  to  fractional  distillation,  the  boiling 
point  rises  from  140°  to  280°.    The  fraction  passing  over  at  170°? 
when  carefully  redistilled,  gave  a  considerable  quantity  of  product 
boiling  at  158° — 159°.    The  formula,  C10H18,  represents  the  compo- 
