^August  1882°'  }    Analytical  Researches  and  Investigations.  399 
pared  the  moiiopotassic  and  the  dipotassic  salt,  the  monoparabroni- 
benzyl-ester,  and  several  products  of  oxidation.  With  strong  oxidizing 
iigents,  like  sulphuric  acid  and  potassium  dichromate,  they  got  only 
;acetic  acid  and  carbon  dioxide,  and  with  nitric  acid  they  got  chiefly 
•oxalic  acid.  With  mild  oxidizing  agents,  like  potassium  perman- 
ganate and  an  alkaline  hydrate,  they  obtained  vanillin,  melting  at 
79°C.,  when  purified,  and  in  another  case  ethylvanillic  acid.  They 
■consider  curcumin  as  a  phenol-carboxylic  acid,  that  is,  a  compound  con- 
taining the  phenol  group  OH  and  the  group  COOH,  carboxyl,  charac- 
teristic of  organic  acids. — Amer.  Chem.  Jour.,  vol.  iv,  p.  77. 
ANALYTICAL  KESEARCHES  AND  INVESTIGATIONS. 
Collated  by  Prof.  Frederick  B.  Power,  Ph.D. 
Examination  of  Butter  for  the  Determination  of  Foreign  Fats  (oleomar- 
garin). — Fifteen  grams  of  the  butter  are  introduced  into  a  capsule  and 
melted  on  the  water-bath ;  after  the  water  and  impurities  have 
•deposited,  the  butter  is  carefully  decanted  and  filtered  upon  a  funnel 
})laced  with  a  small  beaker  in  an  oven,  or  with  a  funnel  surrounded 
Avith  hot  water  and,  after  filtration,  the  limpid  butter  refrigerated. 
The  beaker  is  then  weighed  and  by  means  of  a  glass  rod  three  or  four 
grams  of  the  butter  are  removed  and  introduced  into  a  capsule  of 
twelve  centimeters  diameter,  with  the  rod  and  butter  adhering  thereto; 
the  beaker  is  then  again  weighed  and  the  difference  represents  the 
weight  of  the  butter ;  fifty  cubic  centimeters  of  alcohol  and  from  one 
to  two  grams  of  pure  potassa  are  then  brought  in  the  capsule,  and  the 
liquid  heated  upon  the  water-bath  until  when  water  is  added,  little  by 
little,  it  produces  no  turbidity,  which  is  generally  attained  by  heating 
for  about  five  minutes.  If,  on  the  sudden  addition  of  a  large  quantity 
■of  water,  a  precipitation  of  flocks  of  fat  are  produced,  it  will  be  neces- 
sary to  commence  the  operation  anew. 
The  solution  is  evaporated  on  the  water-bath  to  a  syrupy  consistence, 
the  residue  dissolved  in  one  hundred  to  one  hundred  and  fifty  cubiccenti- 
meters  of  w^ater,  and  the  solution  made  strongly  acid  by  dilute  sulphuric 
acid ;  the  whole  is  then  heated  on  the  water-bath  for  about  half  an 
hour,  until  the  separation  of  the  acids  has  become  quite  comj)lete,  and 
the  aqueous  liquid  is  al>solutely  limpid.  A  filter,  ten  to  twelve  centi- 
meters in  diameter,  of  paper  sufliciently  thick  to  admit  of  hot  water 
passing  through  only  drop  by  drop,  is  dried  at  ]()()°(  \  and  weighed  ; 
