DISTILLATION  OF  PEAT,  BROWN  COAL,  &C. 
531 
inches  diameter,  and  the  retort  was  closed  by  an  iron  plate,  co- 
vered with  clay  and  fixed  by  a  screw.  The  discharge  pipe  of 
the  retort  was  six  inches  long  and  somewhat  inclined.  This  pipe 
was  covered  with  packing  cloth,  kept  moist  during  the  distilla- 
tion, and  was  connected  with  two  two-necked  cylindrical  vessels 
of  sheet  iron  cooled  in  the  same  way  as  the  discharge  pipe. 
By  this  means  the  gas  was  separated  from  the  condensible 
products,  and  was  then  passed  through  some  twenty  feet  of  con- 
densing pipes  before  being  collected  in  the  gasometer. 
After  charging  a  retort,  the  distillation  was  commenced  at  a 
gentle  heat  in  the  first  instance,  and  terminated  at  a  red  heat. 
At  first,  large  quantities  of  water-vapor  were  disengaged,  to- 
gether with  a  little  empyreumatic  oil,  and  it  was  not  until  the 
greater  part  of  the  mechanically  combined  water  was  separated, 
and  after  the  temperature  had  been  raised  to  dull  redness,  that 
a  copious  evolution  of  vapor  took  place,  which,  when  condensed, 
flowed  in  a  thin  stream  into  the  receiver. 
The  gas  that  appeared  during  the  first  stage  of  the  operation 
was  not  combustible ;  consisting  chiefly  of  carbonic  acid.  Af- 
terwards, at  a  higher  temperature,  it  became  combustible,  burn- 
ing with  a  bright  clear  flame,  and  afterwards  with  a  pale  blue 
flame,  being  in  fact  then  carbonic  oxide. 
Sulphuretted  hydrogen,  which  is  produced  in  such  large 
amount  in  the  distillation  of  brown  coal,  &c,  does  not  appear 
among  the  distillation  products  of  peat ;  but  at  the  end  of  the 
operation  a  sensible  amount  of  cyanide  of  ammonium  was  dis- 
engaged. 
The  volatile  liquid  products  of  distillation  collected  in  the 
several  condensation  vessels  were  mixed  together.  The  tar,  be- 
ing of  less  density  than  the  water  liquid,  was  separated  with 
great  ease  by  means  of  a  funnel.  According  to  the  way  in  which 
the  distillation  is  managed,  this  tar  has  a  density  of  from  0.870 
to  0.895. 
The  Hanoverian  peat  was  found  to  yield  on  the  average — 
Tar,   9.0630 
Ammoniacal  water,  .  .  .  40.0000 
Charcoal,  ....  35.3120 
Gas  and  loss,        ....  15.6250 
100.0000 
