GAS  FROM  PEAT. 
71 
GAS  FROM  PEAT. 
There  is  much  discussion  in  connection  with  the  renewal  of 
the  engagements  of  the  city  of  Paris  with  the  gas  companies. 
Attention  has  thus  been  called  to  the  gas  from  peat,  which  for 
some  time  has  been  manufactured  in  Paris.  M.  Leon  Foucault 
has  been  charged  with  measuring  the  comparative  illuminating 
powers  of  coal  and  peat  gas ;  and  the  result  is  in  favor  of  that 
from  peat,  its  power  being  342,  while  that  of  coal  is  100. 
The  manufacture  of  peat  gas  is  more  simple  than  that  of  coal. 
The  peat,  if  put  into  an  iron  retort,  heated  to  a  low  red  heat,  af- 
fords immediately  a  mixture  of  permanent  gases,  and  vapors 
which  condense  into  an  oleaginous  liquid,  which  two  products 
separate  on  cooling.  The  oil  is  collected  in  a  special  vessel,  and 
the  gas  passes  into  a  gasometer.  This  carburetted  hydrogen  is 
wholly  unfit  for  illumination,  it  giving  a  very  small  flame,  nearly 
like  that  from  brandy.  The  oil  from  the  peat  is  a  viscous  black- 
ish liquid,  of  strong  odor  ;  it  is  subjected  to  a  new  distillation, 
and  resolved  wholly  into  a  permanent  gas  and  hydrogen  very 
richly  carburetted.  This  mixture  is  strongly  illuminating,  giving 
a  flame  six  or  eight  times  brighter  than  the  first  and  of  more 
lively  brilliancy.  The  two  are  mixed,  and  a  gas  of  intermediate 
character  obtained,  which  is  delivered  over  for  consumption. 
M.  Foucault  has  made  his  trials  with  a  photometric  method 
which  will  soon  be  made  known.  Its  unit  was  not  a  single  wax- 
candle,  but  a  collection  of  seven  candles,  arranged  in  a  hexago- 
nal manner  with  spaces  of  one  centimeter.  A  single  candle  is 
liable  to  too  much  variation,  a  compensation  for  which  is  secured 
when  a  number  is  employed. 
By  this  method,  a  mean  of  five  determinations  gave  for  a 
burner  of  peat  gas  a  light  equivalent  to  23J  candles;  and  the 
same  burner  with  coal  gas  6,30  candles. 
The  illuminating  power  of  pure  oil  from  peat  the  illuminating 
material  "par  excellence" — has  been  found,  at  equal  pressures, 
705,  the  intensity  for  coal  gas  being  100  ;  and  with  equal  vol- 
umes their  numbers  are  756:  100. — Sillirnans  Journal. 
