3T2 
VARIETIES. 
TABLE  X. 
Action  of  certain  Chemical  Reagents  upon  Infusions  of  Coffee  and  Chicory. 
Raw  Coffee. 
Roasted  Coffee. 
Raw  Chicory. 
Roasted  Chicory. 
A  bright  reddish- 
Brownish-yellow 
liquid,  and  no 
precipitate. 
I\ot  altered. 
Not  altered. 
yellow  liquid, 
and  no  precipi- 
tate. 
Lime-water  
Pa  1  e-y  e  1  low 
liquid;  on 
standing,  b  e  - 
coming  green 
at  the  surface, 
no  precipitate. 
Reddish-brown, 
with  shade  of 
purple,  and  no 
precipitate. 
Not  altered. 
Not  altered. 
Acetate  of  copper... . 
Dirty  green  pre- 
cipitate. 
Brownish-green 
precipitate. 
Pale-green  p  r  e- 
cipitate. 
Gelatinous  pre- 
cipitate of  a 
reddish-brown 
color. 
Perchloride  of  iron,  ■ 
Deep  green  ish- 
black  precipi- 
tate. 
Very  dark  green- 
ish-black pre- 
cipitate. 
Blackish-brown 
colored  liquid. 
No  effect. 
t 
Bright  red-color- 
ed liquid. 
Clear  port-wine- 
colored  liquid. 
No  effect. 
No  effect  at  first; 
on  standing, 
port  wine  co- 
lor. 
Sulphuric  acid  
Dirty  blackish- 
brown-colored 
liquid 
Dark  blackish- 
brown  colored 
liquid. 
Deep  blackish- 
brown-colored 
liquid. 
Brownish-black 
liquid. 
Hydrochloric  acid.. . 
Pale  brownish 
yellow  liquid. 
Port-wine-colored 
liquid. 
No  effect. 
Slightly  darkens 
the  liquid. 
In  allowing  a  solution  of  unroasted  coffee  to  stand,  its  green  color  be- 
comes gradually  deeper.  This  change  is  due  to  oxidation  and  the  forma- 
tion of  the  viridic  acid  of  Rochleder.  It  is  promoted  by  the  presence  of 
an  alkali ;  an  excess  of  lime  brings  out  this  color  very  strongly  in  a  day 
or  two, — giving  at  first,  however,  a  bright  yellow  color.  Subacetate  of 
lead  gives,  in  unroasted  coffee,  a  yellow  precipitate,  which  does  not  become 
green.  An  excess  of  acetate  of  copper  gives  a  green  precipitate  in  abun- 
dance, which  is  brightened  by  the  addition  of  an  alkali.  This  copper  pre- 
cipitate has  been  used  as  a  green  pigment.  The  reactions  above  described 
are,  however,  much  altered  and  obscured  by  the  roasting  of  the  coffee,  and 
are  therefore  of  little  service  for  our  present  purpose. 
It  has  already  been  stated  that  iodine  produces  no  blue  coloration  in  the 
infusion  of  either  coffee  or  chicory.  If  the  reagents  named  act  clearly  in 
a  different  manner  upon  any  infusion  from  what  they  do  upon  pure  coffee, 
a  presumption  of  adulteration  is  obtained,  but  the  indications  must  be  of 
a  positive  and  specific  nature  fully  to  establish  adulteration. 
Coffee  was  submitted  to  the  usual  process  of  distillation  with  soda-lime 
for  the  determination  of  its  nitrogen.  The  proportion  of  nitrogen  per  cent, 
was,  in  coffee,  sample  1  (Table  VII.),  roasted,  2-93 ;  in  sample  2,  roasted, 
