Am.  Jour.  Pharm.  ) 
November,  1913.  J 
Current  Literature. 
533 
is  shaken  with  a  small  excess  of  barium  carbonate.  The  whole  of 
the  free  hydriodic  acid  is  thus  converted  into  soluble  barium  iodide, 
which  in  turn  is  precipitated  as  barium  sulphate;  100  of  barium 
sulphate  corresponds  to  109  of  hydriodic  acid.  By  this  method,  it 
was  found  that  a  tincture  which  had  been  exposed  in  a  colorless 
bottle  to  the  diffused  light  of  the  laboratory  for  9  months,  showed 
the  presence  of  hydriodic  acid  to  the  extent  of  1.42  per  cent. — Jour. 
Pharm.  Chitn.,  July  16,  191 3,  page  75. 
French  Otto  of  Rose. 
Bulgaria's  calamity  has  proved  France's  opportunity.  For  gener- 
ations the  perfumery  world  has  drawn  its  supplies  of  otto  of  rose 
from  the  Balkan  States,  and  up  to  a  few  years  ago  we  were  taught  to 
believe  that  nowhere  else  on  earth  were  climatic  conditions  favorable 
to  its  production,  but  this  summer  we  are  being  treated  to  French  otto 
of  rose  of  excellent  quality  and  at  a  comparatively  low  price.  From 
our  friends,  Vimard,  Dhumez  and  Monschein,  of  Vallauris  (Alpes 
Maritimes),  we  have  just  received  two  samples  of  otto  of  rose  of 
guaranteed  purity.  One  of  these  samples,  prepared  exclusively 
from  one  species  of  rose,  has  the  following  characters : 
Specific  gravity  at  250  C   0.8717 
Optical  rotation   6°  40' 
Melting  point    over  220  C. 
The  other  specimen,  prepared  from  bulked  deliveries  of  various 
kinds  of  roses,  gave  the  following  figures : 
Specific  gravity  at  250  C   0.8679 
Optical  rotation   3°  30' 
Melting  point   over23°  C. 
Although  the  makers  are  not  able  to  state  the  proportions  of  the 
various  species  of  flowers  employed,  they  are  quite  prepared  to 
guarantee  the  purity  of  the  product,  and  one  is  at  a  loss  to  account 
for  the  difference  of  the  figures  for  the  optical  rotation.  Although 
the  rotation  of  the  sample  first  described  is  about  the  same  as  that 
of  an  essence  distilled  from  "  roses  de  Mai,"  that  of  the  specimen  pre- 
pared from  the  mixed  flowers  corresponds  closely  to  the  figure  for 
Bulgarian  otto. 
