12 
Acidum  Oleicum. 
Am.  Jour.  Pharm 
Jan.,  1884. 
the  greater  the  excess  of  lime  ;  but  this  statement  is  in  direct  con- 
tradiction to  experience.  According  to  Jurisch,  the  density  of  the 
liquor  for  caustification  should  not  exceed  14°  Baume* ;  the  author, 
however,  points  out  that  under  ordinary  atmospheric  pressure  it  is 
impossible  to  caustify  denser  liquors  than  these,  for  the  reaction 
became  incomplete  owing  to  a  commencement  of  a  reverse  chemical 
change.  The  author  also  criticises  Jurisch's  statements  as  regards 
the  amount  of  combustible  substance  required  for  the  evaporation  of 
caustic  soda  of  various  densities. 
In  the  remainder  of  the  paper  no  new  chemical  facts  are  detailed  ; 
the  author  quotes,  and  offers  some  critical  remarks  upon  Weldon's 
statements  as  regards  the  extraction  of  ammonia  from  coal,  the  use 
of  pyrites  from  Rio  Tinto  for  the  manufacture  of  sulphuric  acid,  and 
the  total  production  of  sodium  carbonate  from  the  Le  Blanc  and  the 
ammonia  processes  throughout  the  world. — Jour.  Chem.  Soc,  Sept.,  1883. 
ACIDUM  OLEICUM— OLEIC  ACID. 
By  Dr.  E.  R.  Squibb. 
A  yellowish  oily  liquid,  gradually  becoming  brown,  rancid  and  acid, 
when  exposed  to  the  air ;  odorless  or  nearly  so,  tasteless,  and,  when  pure, 
of  a  neutral  reaction.  Sp.  gr.  0'800  to  0'810.  Oleic  acid  is  insoluble  in 
water,  but  completely  soluble  in  alcohol,  chloroform,  benzol,  benzin,  oil  of 
turpentine  and  the  fixed  oils.  At  14°  C.  (57'2°F.)  it  becomes  semi-solid,  and 
remains  so  until  cooled  to  4°C.  (39*2° F.),  at  which  temperature  it  becomes 
a  whitish  mass  of  crystals.  At  a  gentle  heat,  the  acid  is  completely  saponi- 
fied by  carbonate  of  potassium.  If  the  resulting  soap  be  dissolved  in  water 
and  exactly  neutralized  with  acetic  acid,  the  liquid  will  form  a  white  pre- 
cipitate with  test  solution  of  acetate  of  lead.  This  precipitate,  after  being 
twice  washed  with  boiling  water,  should  be  almost  entirely  soluble  in  ether 
(abs.  of  more  than  traces  of  palmitic  and  stearic  acids).  Equal  volumes  of 
the  acid  and  of  alcohol,  heated  to  25°  C.  (77°  F. )  should  give  a  clear  solution, 
without  separating  oily  drops  upon  the  surface  (fixed  oils).—  U.  S.  P. 
Just  now  this  acid  seems  to  be  an  important  addition  to  the  Phar- 
macopoeia, and  a  good  description  and  tests  much  needed.  But  those 
given  above,  which  are  most  definite  and  most  characteristic,  do  not 
apply  to  the  oleic  acid,  which  is  generally  accessible,  and  which  has 
been  exclusively,  or  almost  exclusively,  used  in  this  country  since  the 
oleates  were  introduced  here.  And  if  this  description  and  tests  is  to 
apply  in  future,  the  entire  practice  must  be  revolutionized,  and  this 
writer  does  not  know  of  such  an  oleic  acid,  nor  where  it  is  to  be 
