The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1873-05-31
FARM AND GARDEN.
by AN OLD MASTER-BUuDER
How to Build u Chimney

Having read lately, in He0rM and Home
several articles on the construction OF chin
neys, which fail to give II full and correct ac-
count of the principles involved | want to
give, in brief terms as may be, the m0tius up
eraAdj and rationale of building II chimney
that will draw My remarks apply to all
chimneys, but more particularly to those
with fire place, where wood or coal is to be
used as fuel.
Regard should be had to the proportion ex,
isting between the size of the room and fire
place, and have found in my experience
that, for a room 1920 the fireplace if for IA
kitchcn) should be feet six inches wide in
front between the jambs, and 3 feet high to
mantelbar, and 10 to Is inches deep, with
flare of about inches to each jamb, 50 as to
leave the back Oft the fireplace about feet 6
inches wide; and this should be carried up
plumb feet, and then inclined gradually for
ward inches, to a level with the mantel-b bar,
then plumb two courses of brick; at which
point make an offset AS far back as the depth
of the chimney will allow, and leave inches
thickness for its back. This offset should not
be the full width, but about "a inches will
answer and the tlue which begins at this
point 12y24 inches may be gradually reduced
to 12Xl6 inches, and carried up of this size, to
within IL inches of the top, when it must be
gradually reduced to 12xl2 inches, and well
pargeted throughout. Thus constructed, q
chimney will draw" and serve its purpose
WELL although it is better, where practicable,
TO have an additional offset, or even two or
three of them formed in the tlue-these offsets
lying at right angles, and forming shelf
about inches wide, the tluc being gradually
reduced again to its former size. These OH
sets are usually made at that point where the
course of the flue is changed for the purpose
Of, Il, all rnl fro t,lan 10. fhp
case in building of two or more stories. When
a building is carried to the height of several
stories, the opening at the top of the chimney
may be reduced to 1Oy10 inches. Fireplace
for parlor, or sitting room of usual size,
should not be more than 2 feet 10 inches or
feet between jambs, and feet 8 inches
to mantelbar; and tluc proportionately less.
Our chimney being built in the manner pre-
scribed, we start fire upon the hearth and as
combustion proceeds, the column of air in the
tue, hitherto inert, or nearly 80, becomes
rareticd by the heat and seeks to rise, smoke
laden; and were the column of air in the fiue
larger, or of greater volume in the upper than
the lower portion, the resistance would be too
great, and were there no offsets, the cold air,
seeking to restore an equilibrium disturbed
by the heat below, would rush unimpeded
towards the disturbing element and fill the
room with smoke, presenting all the unpleas
ant phenomena of IA smoking chimney" but
our chimney, not being built wrong. end-up,
the column of cold air is gradually overcome
and the smoke rises beautifully, and whatever
struggles there may be between the heated
and cold columns of air, take place at the off.
sets, where the cold air, in its course striking
upon the shelf, forms an eddy, and the hot
and cold air and smoke intermingle, and
soon the whole column is sufficiently rarefied
to find its way to the chimney-top and es-
cape.
Where houses are not we'll supplied with
atmospheric air, it should be brought by a
pipe to a convenient point and regulated by |
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