126     Production  of  Anilin  Colors  without  Arsenic,{^'^-^^^]ii^^""^- 
quinia  in  500,000  of  water,  when  sulphuric  acid  has  been  added, 
possesses  still  a  visible  flourescence,  which  is  instantly  destroyed  upon 
the  addition  of  hydrochloric  acid,  as  stated  by  Stokes.* 
From  the  facts  above  stated  the  author  deduces  thefollowing  prop- 
ositions : 
(1)  .  The  solubility  of  quinia  in  water  is  at  15°  C,  i  in  2,024, 
at  100°  C,  I  in  760  ;  in  absolute  alcohol,  at  15°  C,  i  in  1,133  ' 
chloroform,  at  15°  C,  i  in  1,926;  in  pure  sulphuric  ether,  at  15°  C, 
I  in  22-632. 
(2)  .  The  solubility  of  tannate  of  quinia  in  warer  is  below  i  in  20,000. 
(3)  .  The  fluorescent  power  of  quinia  becomes  twenty  times  more 
energetic  under  the  influence  of  an  excess  of  sulphuric  acid. 
(4)  .  By  means  of  this  exalted  fluorescence,  it  is  possible  to  recog- 
nize the  presence  of  the  alkaloid  in  a  solution  containing  quinia  only  in 
the  proportion  of  one  part  in  five  hundred  thousand  ;  a  degree  rather 
beyond  that  stated  by  Fiuckiger  who  recommends  this  reaction.  The 
author  finds  it  to  surpass  in  delicacy,  in  the  ratio  of  5  to  4,  the  opales- 
cence caused  by  the  double  iodide  of  mercury  and  potassium,  which, 
however,  furnishes  no  clue  as  to  the  nature  of  the  alkaloid  of  which  it 
reveals  the  existence. 
THE  PRODUCTION  OF  ANILIN  COLORS  WITHOUT  THE  USE  OF 
ARSENIC  ACID. 
It  will  be  within  the  remembrance  of  readers  of  the  Chemical 
News  "  that  Coupler,  of  Paris,  was  the  first  to  succeed  in  producing 
fuchsin  by  the  action,  at  a  suitable  temperature,  of  hydrochloric  acid 
and  iron  in  small  quantities  on  pure  anilin  and  nitrotoluol.  Though 
Coupler's  experiments  were  confirmed  by  Schiitzenberger,  who  showed 
the  anilin-red  obtained  by  Coupler's  process  to  be  identical  with  that 
usually  manufactured,  and  found  the  yield  somewhat  greater  than  that 
obtained  by  the  use  of  arsenic  acid,  the  process  was  not  applied  indus- 
trially before  1872,  when  Meister  Lucius  and  Brlining,  of  Hoechst, 
Germany,  succeeded  in  working  it  on  a  large  scale.  This  firm,  how- 
ever, appear  to  manufacture  their  colors  only  in  part  by  this  method, 
as  they  still  supply  the  market  with  dyes  containing  arsenic. 
More  recently,  the  Gesellschaft  fiir  Anilin  P^abrikation,  of  Berlin, 
have  erected  new  woiks,  where  no  arsenic  acid  is  used  in  the  prepara- 
tion of  colors.     Not  only  fuchsin  (rubin),  but  all  the  colors  derived 
*  "  Loc.  clt." 
