Am.  Jotjr.  Pharm.  ) 
Feb.  1, 1872.  J 
On  Arachis  Oil  in  Olive  Oil. 
81 
heated,  the  passage  of  the  gas  is  interrupted.  After  a  few  hours,  if 
the  contents  of  the  flask  be  poured  into  water,  a  red  coloring  matter 
is  obtained  insoluble  in  water,  soluble  in  alcohol  and  in  alkaline  solu- 
tions, its  color  being  changed  by  the  latter  to  blue  or  green.  The 
formation  of  the  color  is  not  prevented  by  previously  passing  the  gas 
through  dilute  sulphuric  acid,  solution  of  caustic  potash,  or  of  cupre- 
ous chloride  either  in  hydrochloric  acid  or  ammonia,  nor  does  the 
•color  seem  to  be  produced  by  passing  any  of  the  ordinary  constituents 
of  coal-gas  into  the  mixture.  A  similar  substance,  however,  seems  to 
be  formed  by  digesting  the  mixture  of  phenol  and  sulphuric  acid  for 
some  time  at  a  gentle  heat  with  two  or  three  times  its  volume  of  com- 
mercial benzol. — Chemical  JYews,  Dee.  22,  1871. 
TESTING   AND   QUANTITATIVE    ESTIMATION    OF  ARACHIS 
OIL  IN  OLIVE  OIL. 
By  A.  Renard. 
The  author  bases  this  process  upon  the  detection  of  arachidic  acid. 
A  quantity  of  10  grms.  of  the  oil  to  be  tested  is  first  saponified  ;  the 
soap  obtained  having  been  decomposed  by  hydrochloric  acid,  the  fatty 
acids  set  free  are  dissolved  in  50  c.  c.  of  alcohol  at  95  per  cent.,  the 
warm  solution  is  precipitated  by  acetate  of  lead,  and  filtered  after 
having  become  cold.  The  residue  on  the  filter  is  treated  with  very 
strong  and  pure  ether,  which  dissolves  the  oleate  of  lead,  leaving 
margarate,  palmitate,  and  arachidate  of  that  metal.  This  compound 
is  heated,  and  then  treated  with  warm  dilute  hydrochloric  acid ;  the 
fatty  acids  are  separated  by  decantation  from  the  solution  of  chloride 
of  lead.  When  the  fatty  acids  are  cooled,  and  thereby  solidified,  the 
cake  thus  obtained  is  dissolved  in  50  c.  c.  of  alcohol  at  95  per  cent,  by 
the  aid  of  heat;  a  single  drop  of  hydrochloric  acid  may  have  to  be 
added  to  this  solution  in  order  to  render  it  free  from  a  slight  cloudi- 
ness. If  the  olive  oil  operated  upon  happens  to  contain  arachis  oil, 
there  will  separate  from  the  alcoholic  solution,  on  cooling,  ci^stals  of 
arachidic  acid.  In  order  to  estimate  the  quantity  thereof,  the  crystal- 
line mass  is  collected  on  a  filter,  first  washed  with  a  quantity  of  from 
10  to  20  c.  c.  of  the  strong  alcohol  just  alluded  to,  and  next  with  or- 
dinary alcohol,  wherein  this  acid  is  insoluble.  The  substance  upon 
•  the  filter  is  next  treated  with  boiling  hot  absolute  alcohol,  wherein  the 
acid  is  dissolved,  the  filtrate  collected  in  a  previously  weighed  capsule, 
6 
