COLORING  MATTERS  FROM   COAL  TAR. 
41 
variety  of  very  different  compounds  which  will  be  set  free  either 
in  the  state  of  a  permanent  gas,  or  a  condensible  vapor,  and 
leave  fixed  carbon  as  a  residue.  The  same  takes  place  whether 
wood,  coal,  bituminous  schists.  Boghead  coal,  ashphalte,  peat, 
resin,  oils  or  animal  matters  be  distilled  ;  but  it  is  evident  that 
the  original  composition  of  the  material  submitted  to  dry  distil- 
lation must  powerfully  influence  the  nature  and  composition  of 
the  products.  In  those  which  like  wood  are  rich  in  oxygen  and 
poor  in  nitrogen,  the  pyrogenous  products  contain  much  acetic 
acid  and  but  little  ammonia,  and  consequently  have  an  acid  re- 
action ;  on  the  contrary  the  matters  containing  much  nitrogen, 
and  but  little  oxygen,  like  coal  and  animal  matters,  give  rise  to 
the  formation  of  much  ammonia,  and  the  products  have  an  al- 
kaline reaction. 
We  intend  in  this  article  to  confine  our  attention  to  the  pro- 
ducts obtained  by  the  distillation  and  rectification  of  the  coal 
tar  from  gas  works.  Considerable  differences  are  noticed  in  the 
composition  of  the  tar  procured  from  different  qualities  of  coal 
and  schists,  according  to  the  rapidity  with  which  the  distillation 
has  been  conducted.  Some  tars,  for  instance,  contain  but  little 
benzole  and  much  naphthaline  ;  Boghead  tar  is  rich  in  paraffine  ; 
others  contain  a  preponderating  quantity  of  phenol  and  ben- 
zole. 
Table  of  the  Products  obtained  by  the  Distillation  and  Rectification  of  Coal  Tar. 
Solid  Products. 
Carbon. 
Naphthaline. 
Paranaphtha- 
line,  or 
Anthraceine. 
Paraffine. 
Chrysene. 
Pyrene. 
Liquid  Products. 
Acids. 
Neutral. 
Bases. 
Graseous 
Products. 
Rosolic. 
Water. 
Ammonia. 
Hydrogen. 
Brunolic. 
Essence  of  tar. 
Methylamine. 
Carburetted 
Phenic,  or 
Light  oil  of  tar. 
Ethylamine. 
hydrogen. 
Phenol. 
Heavy  oil  of  tar. 
Aniline. 
Bicarburetted 
Acetic. 
Benzole. 
Qiiinoline. 
hydrogen. 
Butyric. 
Toluole. 
Picoline. 
Various  hy- 
Cumole. 
Toluidine. 
drocarbides. 
Cymole. 
Lutidine. 
Carbonic 
Propyle. 
Cumidine. 
oxide. 
Butyle. 
Pyrrhol. 
Sulphide  of 
Amyle. 
Psetinine. 
carbon. 
Caproyle. 
Carbonic  acid. 
Hexylene. 
Hydrosul- 
Heptylene. 
phuric  acid. 
Hydrocyanic 
acid. 
Whatever^may  be  the  composition  of  the  different  kinds  of  tar, 
