136       NOTE  ON  PURIFIED  ESSENTIAL  OIL  OF  ALMONDS. 
communication  I  had  the  honor  of  reading  at  one  of  the  evening 
meetings  of  this  Society.  I  suggested,  at  that  time,  that  it  was 
probable  this  essential  oil  might  be  rendered  more  permanent 
than  in  the  purified  state  it  is  generally  found  to  be  by  introdu- 
cing into  it  some  fused  chloride  of  calcium,  so  as  to  remove  from 
it  the  last  traces  of  moisture. 
These  specimens  I  produce  in  support  of  that  suggestion  ;  they 
have  been  prepared  upwards  of  two  years,  and  have  been  pre- 
served side  by  side  under  precisely  the  same  conditions.  The 
one,  as  you  see,  is  filled  with  crystals  of  benzoic'  acid ;  the 
other  in  which  is  placed  a  fragment  of  chloride  of  calcium,  is 
perfectly  free  from  crystalline  deposit,  and  remains  quite  fluid. 
These  bottles  seem  to  me  to  exhibit  clearly  the  very  decided  in- 
fluence of  perfect  drying.*  Shortly  after  the  publication  of  my 
paper,  a  wholesale  drug  firm  in  this  city  wrote  to  the  "Pharma- 
ceutical Journal,"  announcing  that  the  purified  essence  prepared 
by  their  process  was  perfectly  free  from  the  objection  attaching 
to  purified  oil  of  almonds  in  general,  being  permanent  and  in- 
alterable for  any  indefinite  period.  As  this  was  quite  in  oppo- 
sition to  the  remarks  made  by  myself  and  others  at  the  meeting 
referred  to,  I  was  anxious  to  test  their  statement,  it  being  an 
interesting  point  to  determine,  whether  it  were  indeed  possible 
to  render  the  almond  essence  less  susceptible  of  oxidation.  I 
accordingly  procured  a  quantity  of  this  essential  oil. 
It  was  examined,  first  of  all,  for  the  evidence  of  change,  for 
benzoic  acid.  It  was  found  to  be  strongly  acid  to  test-paper, 
although  no  crystallization  was  apparent. except  at  the  stopper. 
This  circumstance,  coupled  with  the  limpidity  of  the  liquid,  and 
its  sp.  gr.,  which  was  as  low  as  1*003  or  thereabouts,  led  me  to 
suspect  the  admixture  of  spirit  of  wine.  On  application  of  Dr. 
Redwood's  test,  fuming  nitric  acid,  it  gave,  as  anticipated,  abun- 
dant evidence  of  alcohol  by  the  violent  evolution  of  nitrous  fumes. 
Here  also,  proof  was  obtained  that  the  change  effected  in  the 
liquid  by  the  air  was  in  an  advanced1  stage,  for,  on  cooling,  the 
*I  am  informed  by  Mr.  C.  Umney,  who  is  in  the  habit  of  purifying  es- 
sential oil  of  almonds  on  a  large  scale,  that  he  has  found  the  above  plan 
of  desiccation  by  means  of  chloride  of  calicum  to  succeed  perfectly  in 
preventing  change  in  the  purified  oil. 
