South Bend news-times. (South Bend, Ind.) 1913-1938, 1916-12-19
Building Chimneys
Ancient, Exact and
Difficult Science
By Garrett p. Scryiss.

why is it when you light up a kero-
sene lamp IL burns with bright name
when fl has the glass over, but it smokes
when the glass is removed "A. W.
Newark
If you hold your hand a foot
above the bare flame Of your lamp
before the glass is put on you will
feel no great heat, but when the
glass is on the heat becomes intense.
This shows you that the glass acts
as a chimney. combining the air
heated by the flame. and guiding il
in a narrow current upward.
The Chimney Makes the Hot Air As
IL Rises Draw Cold Air In.
The heated air rises because II
is lighter than the surrounding air,
and. as il rises, colder air comes
in at the bottom, from all sides, TO
take its place. If you study the
construction Of your lamp you will
see that openings are left around the
flame. under the bottom of the glass
chimney. for the purpose of admit
ting the air that rushes in below 70
replace the heated air that is go
ing up and out of the chimney.
Now, combustion. or burning, can
not be maintained without a con-
tinual supply Of oxygen. which com
bines chemically with the heated
gases from the OIL and the needed
oxygen comes from the air, about
one-fifth of which consists Of pure
oxygen If the same air is contin-
ually exposed 20 the flame, the oXy-
gen will quickly be all burnt out Of
il. and then the flame will expire.
If the supply of oxygen is too
small the combustion of the car
bon-charged gases arising from the
oil will be incomplete and the flame
will be choked with smoke, which
consists of only partially burned
particles of carbon.
Thus the Chimney Keeps Current
of Air Flaming Through 1t.
That is the situation when you
have lighted the lamp but have not
yet put on the chimney, for then
the air from the surrounding at
mosphere does not flow in fast
enough TO maintain the needed sup
plv of oxygen. But the moment the
chimney = set in place a draught,
or current. of heated air begins 10
ascend through il, leaving room at
the bottom for fresh air TO come in,
loaded with oxygen, and the fresh
air will come in because of the
pressure TO which il is subjected by
the surrounding atmosphere.
Thereupon the flame brightens
and steadies because now there is
constantly enough oxygen on hand
10 produce complete combustion Of
the gases. The brilliancy of the
flame is principally due TO minute
particles of carbon, derived from
the oil and heated TO a bright in
candescence.
Chimneys are one OF the most use
ful and interesting inventions that
man has ever made. They are of
wider and more essential import
ance than anything that Edison. or
any other great modern inventor,
has contrived, but we do not know
who made she first chimney. In a
primitive form they must be almost
as old as the human race, for fire
could not be made to burn with any
regularity without a draught to
keep up the supply Of oxygen. The
first chimneys may have been nat
uraI ere ices in the walls and roofs
OF caverns which were gradually i'm
proved. artifcially. as men per-
ceived. without thoroughly under
standing. how they acted.
Then. probably. stones were piled
together 10 form rude chimneys. as
a s.lilful camper piles them today
10 cook his food on the seashOre,
or in the forest. Indian wigwams
were turned into very smoky and
ineffective chimneys by making an
opening in the center OF the roof.
IL Takes An Engineer TO Make a
Good Chimney. Whatever the size
II takes an engineer 10 make a
good chimney. and he must under
stand many OF the laws OF nature.
Modern factory chimneys are tri-
umphs OF scientific construction.
They have 10 be made tall in order
To maintain a large. hot IRE. and