The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1915-01-14
HEAT VALUE OF WOOD
AND COAL COMPARED
VALUABLE INFORMATION RE.
suit OF EXPERIMENTS BY
FOREST SERVICE.

iHe luei Fdluc OF TWO pounds OF
wood is roughly equivalent 10 that O
one pound ot coal This is given as
the result of certain calculations now
being made in the forest service lab.
oratory, which show also about how
many cords Of certain kinds of WOOD
are required to obtain an amount O.
heat equal to that in ton Of coal.
Certain kinds Of wood, such as HE.
kory, oak, beech, birch, hard maple
ash, elm, locust longleaf pine ant
cherry, have fairly high heat values
and only one cord of seasoned WOOD
OF these species is required to euua
one ton of good coal.
! 1t takes a cord and a half of short.
leaf pine, hemlock, red gum, Douglas
FIR, sycamore and soft maple to eauaI
a ton Of coal and two cords of cedar
redwood, poplar catalpa, Norway pine
cypress, Eastwood, spruce and white
pine.
Heavier the Wood the More Heat.
Equal weights of dry, -resinous
woods, however, are said to have prac-
tically the same heat value regardless
OF Species and as a consequence II
can be stated as a general proposition
that the heavier the wood the more
heat to the cord. Weight for weight
however, there IS very little difference
between various species the aver.
age heat for all that have been calcu-
lated is 1900 calories, or heat units
per kilogram. A kilogram of resin
will develop 94O0 heat units or about
twice the average for wood. As a CON
sequence, resinous woods have 9
greater heat value per pound than non
resinous woods. and this increased
value varies, Of course, with the resin
content.
The available heat value of a cord of
wood depends on many different fac
tors. 1t has a relation not only to the
amount Of resin it contains but to the
amount Of moisture present Further
more, cords vary as to the amount Of
solid wood they contain, even when
they are Of the standard dimension
and occupy 12S cubic feet of space. \
certain proportion of this space is
made up of air spaces between the
sticks, and this air space may be con-
siderable in a cord made of twisted,
crooked and knotty sticks. Out of the
l2S cubic feet, fair average of solid
wood is about 50 cubic feet.
Hickory Heads List.
1t is pointed out, however that heat
value is not the only test of usefulness
in fuel wood and since 95 per cent of
all wood used for fuel is consumed for
domestic purposes, largely in farm
houses, such factors as rapidity Of
burning and ease of lighting are i'm
pOrtant. Each section of the country
has its favored woods and these are
said to be in general, the right ones to
use. Hickory, Of the -resinous
woods, has the highest fuel value per
unit volume of wood, and has other
advantages. 1t burns evenly, and, as
housewives say, holds the heat The
oaks come next, followed by beech,
birch and maple. Pine has a relatively
low heat value per unit volume, but
has other advantages. 1t ignites read
lily and gives out a quick, hot flame,
but one that soon dies down. This
makes it a favorite with rural house
keepers as a summer wood. Because
it is particularly adapted for hot days
in the kitchen.
The fuel qualities of chestnut adapt
it particularly to work in brass foun-
deries where it gives just the required
amount Of heat and it is therefore in
favor Coastwisc vessels in Florida
pay twice as much for Florida button
wood as for any other because it
burns with an even heat and a mini
mum amount of smoke and ash.
The principal disadvantage of the
resinous pines is their only black
smoke.
Ny Auto-'Tis Of Thee.
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