252     PREPARATION  OF  ARTIFICIAL  CQLORINa  MATTERS,  ETC. 
patent,  in  November,  1859,  extended  the  list  of  colorige- 
nous  agents,  by  including  the  stannous  and  stannic  sul- 
phates, the  mercurous  and  mercuric  sulphates,  the  mercu- 
rous  and  mercuric  nitrates,  nitrate  of  silver,  titanic  chlo- 
ride, mercuric  fluoride,  stannic  and  mercuric  bromides,  and 
stannic  iodide.  A  third  addition,  in  the  same  month,  added 
the  ferric  and  uranic  nitrates,  uranic  chloride  and  mercuric 
chlorate,  bromate,  and  iodate.  Sesquichloride  of  carbon  and 
and  iodoform  were  afterwards  added  in  December  of  the  same 
year.  Lastly  a  fifth  addition  was  made  in  February,  1860,  the 
purport  of  which  the  author  does  not  exactly  know,  but  which, 
he  believes,  includes  iodine,  arsenic  acid,  and  nitric  acid. 
We  must  here  quote  from  a  paper  by  Dr.  Hofmann,  presented 
to  the  Academy  of  Sciences,  on  September  20th,  1858,*.  and 
entitled,  '<  Contributions  to  the  History  of  the  Organic  Bases, 
iv.  Action  of  Bichloride  of  Carbon  on  Aniline:" — * 
"  At  the  ordinary  temperature  of  the  air,  aniline  and  bichloride  of  car- 
bon do  not  act  on  each  other.  At  lOO''  C.  the  mixture  begins  to  change; 
but  after  digesting  for  some  days,  the  change  is  far  from  being  complete. 
By  submitting,  however,  a  mixture  of  one  part  of  bichloride  of  carbon  and 
three  parts  of  aniline,  the  two  bodies  being  in  the  anhydrous  state,  to  a 
temperature  of  170°  or  180°  (the  boiling  point  of  aniline)  for  nearly  thirty 
hours,  the  liquid  is  changed  into  a  blackish  mass,  soft  and  viscous,  or  hard 
and  brittle,  according  to  the  duration  of  the  temperature.  This  blackish 
mass  is  a  mixture  of  several  bodies.  By  exhausting  with  water  a  part  is 
dissolved,  another  part  remaining  insoluble  in  a  resinous  state.  With 
the  aqueous  solution  potash  gives  an  oily  precipitate,  which  contains  a 
considerable  proportion  of  unchanged  aniline.  On  distilling  this  oily 
matter  with  diluted  potash,  aniline  passes ;  while  a  viscous  oil,  which 
solidifies  by  degrees,  remains  behind.  Repeated  washings  with  cold 
alcoht  l,  and  one  or  two  crystallizations  from  boiling  alcohol,  render  the 
body  perfectly  white  and  pure  ;  a  very  soluble  substance  of  a  magnificent 
crimson  color  remaining  in  solution. 
The  blackish  portion  of  the  mass  which  remains  insoluble  in  water,  is 
easily  dissolved  by  hydrochloric  acid  ;  from  this  solution  it  is  again  pre- 
cipitated by  alkalies,  as  a  dirty-red  amorphous  powder  soluble  in  alcohol, 
and  forming  a  rich  crimson  colored  solution.  The  greater  part  of  this 
coloring  matter  is  the  same  as  that  which  accompanies  the  crystalline 
fatty  body,  considerable  quantities  of  this  latter  substance  being  some- 
times found  in  the  product  insoluble  in  water." 
The  great  resemblance  between  the  experiments  of  Dr.  Hof- 
Comptes-Rendus,  t.  xlvii.  p.  492. 
