ON  THE  PURIFICATION  OF  ESSENTIAL  OIL  OF  ALMONDS.  145 
freeze  at  any  degree  of  cold  meters  are  subject  to,  and  render- 
ing them  free  from  the  attention  necessary  if  filled  with  whisky 
or  water. 
It  deserves  attention  as  a  lubricator  for  fine  machinery,  not 
congealing  or  being  affected  by  exposure  to  the  atmosphere. 
Numerous  other  applications  have  been  made  of  it,  and  its 
uses  will  increase  as  its  wonderful  properties  become  known. 
ON  THE  PURIFICATION  OF  ESSENTIAL  OIL  OF  ALMONDS. 
BY  WILLIAM  A.  T1LDEN, 
Demonstrator  in  the  Laboratory  of  the  Pharmaceutical  Society. 
Among  the  numerous  processes  that  have  been  suggested  for 
the  purification  of  essential  oil  of  almonds  from  the  prussic  acid 
that  it  invariably  contains,  I  believe  there  are  none  that  are 
completely  satisfactory,  and  some  short  time  ago  I  was  induced 
to  make  a  few  experiments  in  a  new  direction,  with  a  view  to 
finding  a  process  for  the  purification  of  this  essential  oil  that 
should  not  be  subject  to  the  objections  to  which  the  others  are 
liable.  Although  I  believe  I  have  been  to  a  certain  extent  suc- 
cessful, I  wish  merely  to  present  some  suggestions  in  order  that 
some  one  who  may  have  opportunities  of  working  on  a  larger 
scale  may,  if  so  minded,  repeat  my  experiments. 
I  have  several  times  made  use  of  a  process  founded  upon  a 
long-known  reaction,  and  which  consists  in  splitting  up  the  hy- 
drocyanic acid  into  formic  acid  and  ammonia  with  the  assistance 
of  the  elements  of  water, — 
HC2N+2H202=NH3+C2H204, 
this  change  being  effected  by  the  action  of  a  strong  mineral 
acid. 
Now  when  this  decomposition  is  brought  about  in  the  presence 
of  hydride  of  the  benzoyl,  formic  acid  is  not  set  at  liberty,  but 
unites  with  the  elements  of  the  hydride,  producing  a  conju- 
gate acid,  to  which  the  name  formo-benzoylic  acid  has  been  ap- 
plied. 
Its  composition  is  represented  by  the  following  formula  : — 
C14H602,C2H204.  This  body  is  easily  formed  by  boiling  a  mix- 
ture of  the  distilled  water  of  bitter  almonds  and  hydrochloric 
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