Obs.  When  butter  is  saponified  with  caustic
putassa  or  soda,  and  the  resulting  soap  decom-
posed by  adding  an  acid.  In  excess,  and  dis-
tilling the  mixture,  the  four  acids  above
named  pass  over  into  the  receiver,  in  combi-
nation witli  wattr.  The  mixed  acids  may  be
separated  by  saturating  them  collectively  with
baryta,  and  by  taking  advantage  of  the
unequal  solubility  of  the  newly  formed  barium
salts.  The  less  soluble  portion  (equal  to  about
^'ijth  of  the  dry  mass)  contains  capric  and  ca-
prylic  acid;  the  larger  and  more  soluble
portion,  butyric  and  caproic  acid.  On '  the
same  plan  the  two  groups  are  resolved  into
their  separate  acids.  These  acids  are  deprived
of  their  uncombined  water  by  means  of  chloride
&f  calcium.  It  is  advisable  to  employ  the  term
rutic  acid,  as  the  older  term  is  easily  con-
ibimded  with  caproic  and  caprylic.
Prop.  Capric  or  rutic  acid  crystallises  in
fine  needles,  which  fuse  at  86"  Fahr.,  giving


out  an  odour  resembling  that  of  a  goat.     It
is  sparingly  soluble  in  boiling  water.
Frep.  (Miller.)  Castor  oil  is  saponified  by
means  of  potassa  or  soda,  and  afterwards  an
excess  of  the  hydrated  alkali  is  added,  amount-
ing to  one  half  the  oil  used.  The  mass  is
heated  in  a  retort,  and  an  oily  liquid  covered
with  water  distils  over.  This  oily  liquid,
which  is  the  octylic  alcohol,  is  rectified  several
times  with  potassa  until  the  residue  is  no
longer  coloured  brown. — Prop.  A  colourless
liquid,  of  powerful  aromatic  odour ;  insoluble
in  water,  but  dissolving  readily  in  acetic  acid,
ether,  and  alcohol.  Its  boiling  point  is  356°
Fr.,  its  sp.  gr.  823.  The  caprylate  of  ethyl,
erroneously  termed  caprylic  ether,  is  a  colour-
less liquid,  with  an  agreeable  odour  of  pine-
apples.
