618 
Acids  from  Drying  Oil. 
Am.  Jour.  Pharm. 
Dec.,  18a7. 
oxide.  Potassium  cyanide  dissolves  it  readily,  and  the  sulphide  is  re- 
precipitated  by  boiling  the  solution  with  excess  of  hydrochloric  acid. 
This  reaction  gives  a  good  means  of  purifying  the  sulphide  from  free 
sulphur,  as  a  slightly  warmed  solution  of  potassium  cyanide  dissolves 
the  former  and  not  the  latter.  When  heated  in  a  tube,  part  of  the 
sulphur  distils  off,  and  part  passes  off  as  sulphurous  anhydride.  The 
compound  is  completely  decomposed  at  240°,  and  ignites  in  oxygen  at 
a  low  temperature.  When  heated  in  a  stream  of  hydrogen,  hydro- 
gen sulphide  is  formed;  but  in  a  stream  of  hydrogen  chloride  the  sul- 
phur sublimes  without  the  formation  of  any  hydrogen  sulphide,  and 
pure  gold  is  left. 
The  existence  of  a  soluble  aurous  sulphide  and  a  soluble  aurous  ox- 
ide (Kriiss,  Untersuchun gen  ilber  das  Atomgewicht  desGoldes,  Munchen, 
1885)  speaks  strongly  in  favor  of  placing  gold  in  the  alkali-group 
rather  than  in  the  platinum-group. 
ACIDS  FROM  DRYING  OIL.1 
By  K.  Hazuea. 
Peters,  Dieff,  Reformatzky,  and  the  author  have  on  different 
grounds  concluded  that  the  formula  of  linoleic  acid  is  C18H3202  and 
not  C16H2802.  In  order  to  set  this  point  at  rest,  the  author  has  un- 
dertaken the  present  research.  When  sativic  acid  is  oxidized  with 
alkaline  potassium  permanganate,  the  only  solid  product  obtained  is 
azelaic  acid. 
When  linoleic  acid  is  treated  with  bromine,  the  hexabromo-com- 
pound,  C18H30Br6O2,  is  the  only  product.  When  the  tetrabromo-deri- 
vative  of  the  acid  from  hemp  oil  is  treated  with  excess  of  bromine,  no 
further  bromination  takes  place,  showing  that  the  above-mentioned 
hexabromo-compound  is  not  derived  from  this. 
The  linoleic  acid  from  linseed  oil  gave  an  "  iodine  value  w  which 
corresponds  with  a  mixture  of  two  acids,  one  with  the  formula  C18H33 
02,  the  other  with  the  formula  ClsH30O2.  The  formation  of  a  tetra- 
and  hexa-bromo-derivative  and  of  linusic  acid  and  sativic  acid  on  oxi- 
dation also  support  the  view  that  linoleic  acid  is  a  mixture.  The  au- 
thor prepared  the  C18H3202  acid  from  the  tetrabromo-compound  and 
1Monatsh.  Chem.,  8,  260.  Reprinted  from  Jour.  Chem.  Soc,  October,  1887,  p. 
913. 
