122  Examination  of  Coffee.  {^""£"'1881™' 
longer  than  the  latter.  It  is  also  extensively  used  to  adulterate  olive 
oil. 
Mustard  seed  oil  is  sold  in  the  San  Francisco  market  at  a  dollar  the 
gallon  in  five-gallon  cans,  and  a  dollar  and  a  quarter  in  one-gallon  cans.. 
— Jour,  of  App.  Sc.,  Jan.,  1881,  p.  5. 
A  NEW  METHOD  for  the  EXAMINATION  of  COFFEE. 
By  F.  M.  Rimmington. 
I  think  it  will  be  generally  admitted  that  the  methods  in  use  for 
estimating  the  degree  of  adulteration  in  coffee  are  far  from  satisfactory 
as  regards  definiteness  and  certainty,  and  that  something  approaching 
nearer  to  chemical  accuracy  is  very  desirable.  Little  has  been  done 
in  this  direction  since  the  days  of  the  ''Lancet''  Sanitary  Commission. 
It  may,  possibly,  not  be  generally  known  to  analysts  that  chicory, 
dandelion  and  probably  some  other  substances  that  are  used  for  mixing 
with  cotfee,  are  readily  deprived  of  color  by  a  weak  solution  of  chloride 
of  lime  (hypochlorite),  and  that  this  agent  has  very  little  action  on  the 
coffee.  When  this  method  is  adopted  a  portion  of  the  coffee  should 
be  gently  boiled  a  short  time  in  water  with  a  little  carbonate  of  soda, 
so  as  to  remove  extractive  as  much  as  possible;  after  subsidence  the 
liquor  should  be  poured  olf,  and  the  residue  washed  with  distilled 
water.  When  this  has  been  sufficiently  done,  a  weak  solution  of  the 
hypochlorite  of  lime  is  to  be  added  and  allowed  to  remain,  with  occa- 
sional stirring,  until  decoloration  has  taken  place,  which  will  probably 
be  in  two  or  three  hours.  The  coffee  will  then  form  a  dark  stratum 
at  the  bottom  of  the  glass,  and  the  chicory  a  light  and  almost  white 
stratum  floating  above  it,  and  showing  a  clear  and  sharp  line  of  separ- 
ation. 
The  chicory  after  this  operation  is  in  the  very  best  condition  for 
microscopical  examination,  and  it  is  not  difficult  to  discriminate  between 
chicory,  dandelion  or  other  substances.  Although  the  lower  stratum 
may  be  dark,  and  have  all  the  appearance  of  coffee,  other  substances 
may  be  present  and  should  be  sought  for.  I  have  recently  met  with 
a  substance  which  is  entirely  new  to  me,  as  a  coffee  substitute,  that  is 
not  affected  by  this  treatment. — Phar.  Jour,  and  Tra.ns.,  Jan.  1,  1881. 
