301 
FUEL 
Is Manu- 
t 
Now i 
It was originally a by-product 
the manufacture of illuminating gas. 
factured expressly for metallurgical purposes, the ovens 
being so constructed that the inflammable gases driven off 
smokeless fuel is required. 
in 
are made to serve largely as a source of heat in the process. 
PAN \\\ vi 
My 
sn 
cale- 
go 
) 
illon 
ron sp 
(Ba 
iod 
(Lepidodend 
Ss 
s 
om the coal per 
-mo 
Fr 
giant club 
a 
of 
tree Family, Lepidodendracee) 
Fic. 278.—Fossil remains 
g coal or wood to a 
igh temperature in a retort, and collecting and purifying the 
ubjectin 
Q 
» 
ff. For obvious reasons coal-gas has proved to be 
a most convenient fuel especially adapted for household use 
Illuminating-gas is made by 
gas given o 
large cities. 
The study of fuels leads one to th 
in 
not only of the forests 
ink 
