168  ESSENCE  OP  COGNAC  AND  OF  WINE. 
219  grains  troj  were  used,  of  which  (137)  one  hundred  and 
thirty-seven  grains  remained  undissolved,  the  difference,  (82) 
eighty  two  grains,  representing  the  amount  of  camphor  in  solu- 
tion in  one  imperial  gallon  of  the  British  preparation,  or  about 
half  a  grain  to  the  fluidounce,  or  one  grain  of  camphor  to  936 
grains  or  minims  of  water ;  being  quite  near  the  statement 
made  by  Berzelius,  that  one  part  of  camphor  is  taken  up  by 
1000  parts  of  water  by  rubbing  them  together. 
The  statement  contained  in  the  U.  S.  Dispensatory,  given 
on  the  authority  of  Wm.  Hodgson,  Jr.,  that  "  our  own  officinal 
preparation,  when  properly  made,  contains  about  50  grains  to 
the  pint,  or  more  than  3  grains  to  the  fluidounce,"  is  incorrect ; 
it  only  holds  in  solution  thirty- two  (32)  grains  of  camphor  in 
each  pint,  or  two  (2)  grains  in  each  fluidounce. 
The  United  States  Pharmacopoeia  Camphor  Water  contains 
two  grains  of  Camphor  to  the  fluidounce. 
The  British  preparation  contains  about  half  (J)  a  grain  of 
Camphor  in  each  fluidounce. 
The  U.  S.  P.  preparation  is  thus  proved  to  be  four  times  the 
strength  of  the  British  preparation. — Proc.  of  the  Amer.  Pharm. 
Assoc.,  1865. 
Boston,  September,  1865. 
ESSENCE  OF' COGNAC  AND  OF  WINE. 
This  is  a  mixture  of  several  ethers  of  the  ethylic  series,  but 
of  which  the  special  odor  is  that  of  pelargonic  ether.  The 
essences  may  be  prepared  in  two  ways  :  the  first  gives  nearly 
pure  pelargonic  ether ;  the  other,  mixtures  of  very  variable 
composition,  and  apparently  inferior  in  quality.  By  the  first 
method,  pelargonic  acid  is  obtained  by  treating  oil  of  rue  by 
nitric  acid ;  to  etherize  pelargonic  acid,  dissolve  it  in  concen- 
trated alcohol,  and  pass  into  the  mixture  a  current  of  dry  hy- 
drochloric acid  ;  the  pelargonic  ether  rises  to  the  surface  as  it 
forms.  By  the  second  method,  a  fatty  body  is  treated  by  nitric 
acid,  and  fixed  fatty  acids  are  produced,  such  as  adipic,  pimelic, 
lauric,  succinic,  &c,  and  also  volatile  acids,  which  may  be  dis- 
tilled, and  of*  which  the  chief  are  butyric,  valerianic,  capric, 
