Evening star., 1921-12-25

u
by train, trolley or auto,
" or that humblest way of
travelling, afoot, you will
see d group of structures of stone,
brick and sheet iron. Some of these
are built of old and hard-burnt brick
and are in the form of giant hogs
heads bound with massive iron hoops.
These are ore roasters. or ore ovens.
You know that ores are sometimes
roasted, or calcined, to eNpel sui
phur and some other minerals. the
| heat volatilizing them. The tall
sheet-iron structure is the elevator
shaft, through which the ore, char
of the stack" The heavy, tower
like structure of brick is the stack" !"
Perhaps, my reader. your notions
concerning melting iron out of rock
are as hazy as mine were until l
explored and hung around the old
Muirkirk furnace, got instruction
from a man who knows as much
about furnaces and charcoal irons
as anybody in the United States and
then did some reading up" on IRON
making. 1t is very big subject
and to understand it is a mans job.
am going to administer bit Of
education to you by explaining the
stack" and the easiest way to give
you a little picture of it is to read
this from the Encyclopedias Britain
MICA: "The iron blast furnace, a
crude but very efficient piece of ap-
paratls. is an enormous shaft usu-
ally about eighty feet high and
twenty feet wide at its widest part.
1t is at all times full from top to
of fuel, ore and limestone, which
are charged through a hopper at the
top. and descend slowly as the lower
end of the column is eaten on
through the burning away of its
coke by means Of very hot air or
blast blown through holes, or
'tuyeres,' near the bottom. or HEARTH
and through the melting away. by
the heat thus generated. both of the
iron itself, which has been deoAid-
ized in its descent, and Of the other
minerals of the ore, called the
'gangue,' which united with the lime
of the limestone and the ash of the
fuel, form d complex molten stlicate
called the 'cinder' or Stag"
I. = !: x
THEN follows an account of the ac-
ton of gases, which We will omit
because one must be up In chemis-
try to understand it. and then this:
The solid column gradually sinks to-
ward the hearth till at the fusion
lever the solid matter has become so
hot that the now deoxidiZed iron
melts, as does the Stag as fast as 1t
is formed by the union Of its three
constituents-the gangue, the lime
from the decomposition Of the lime
stone and the ash OF the fuel. Hence
from this level down is the coke. in
Jumps which are burning rapidly and
hence shrinking. while between them
the molten iron and molten Stag
trickle to collect in the hearth in two
layers, as distinct as water and oil.
the iron below. the Stag above. AS
they collect the molten iron is drawn
off at intervals through hole tempo
rarily stopped with clay, at the very
bottom. and the Stag through another
hole a little higher up called the
'cinder NOTCH"
That describes furnace where
coke is the fuel instead of charcoal.
but for our rough and ready purpose
it ought to give a conception of the
old furnace which stands about four
teen miles from Washington, and of
the hundred or SO other old furnaces
which have made" iron in this Ticin-
ity since the United States was a set
of colonies.
Near the stack is great cistern
built of stone. and there is maze of
water pipes connected with well
and pump. Without knowing it as a
fact, the Rambler assumes that this
water plant was used for cooling the
outside of the stack to aid in the
preservation of the walls, for the
combined fuxing and abrading action
of the descending charge tends to
wear the lining of the furnace where
it is hottest, which, of course, is near
it's lower end, lessening its efficiency