COLORING  MATTERS  OF  FLOWERS. 
547 
the  alcoholic  infusion  of  these  flowers  be  digested  with  a  little  dry 
powdered  hydrate  of  alumina,  the  latter  acquires  a  light  yellow 
color,  and  the  supernatant  fluid  becomes  of  a  fine  red  color  under 
the  influence  of  acids,  and  of  a  blue  without  the  least  mixture  of 
green  by  the  action  of  bases.  The  verbena  consequently  contains 
two  distinct  matters,  of  which  one  becomes  blue  under  the  influence 
of  bases,  whilst  the  other  becomes  yellow ;  it  is  to  the  mixture  of 
these  two  matters  that  the  green  color  of  the  alcoholic  tincture  of 
these  flowers  is  due. 
The  petals  oi  Anemone  hortensis  act  like  those  of  the  verbena. 
The  flowers  of  the  red  paBony  become  of  a  pure  blue  color  under 
the  influence  of  ammonia.  These  flowers  are  rapidly  deprived  of 
color  by  alcohol ;  the  tincture  which  they  furnish  is  but  slightly 
colored,  but  it  becomes  of  a  deep  and  bright  red  by  the  addition  of 
the  smallest  trace  of  acid.  The  acidulated  liquid  becomes  blue 
with  ammonia,  whilst  thenon-acidulated  alcoholic  solution  acquires 
a  greenish  tint.  The  petals  of  dark  red  roses  become  blue  when 
exposed  to  ammoniacal  vapors,  but  the  color  soon  passes  to  a 
greenish-blue.  Alcohol  readily  dissolves  the  coloring  matter  of 
roses,  but  acquires  very  little  color.  The  slightest  addition  of 
acid  communicates  a  deep  red  color  to  the  alcoholic  solution  ; 
ammonia  poured  into  the  acidulated  liquid  changes  it  to  a  greenish 
blue. 
Rose-colored  Flowers — These  flowers  contain  a  mixture  of 
two  juices,  of  which  one  is  colorless  in  acid  liquids,  whilst  the 
other  is  red.  The  former  becomes  yellow  when  mixed  with  alka- 
lies, the  second  becomes  blue,  and  the  mixture  of  these  latter  co- 
lors produces  a  green  tint.  Hence  the  tints  which  will  be  ac- 
quired by  red  or  rose-colored  flowers,  when  exposed  to  the  action 
of  ammoniacal  vapors,  may  be  easily  indicated  beforehand.  It  is 
clear  that  the  green  color  will  approach  yellow  more  and  more  in 
proportion  to  the  paleness  of  the  rose,  and  that  it  will  have  a 
blue  tendency  in  proportion  as  the  color  becomes  deeper. 
Blue  Flowers. — The  preceding  statements  regarding  red  and 
rose-colored  flowers,  applies  also  to  blue  flowers.  The  green 
color  produced  in  blue  flowers  by  the  action  of  watery  ammonia, 
tends  more  and  more  to  yellow  in  proportion  to  the  paleness  of 
the  flower. 
