Evening star. [volume] (Washington, D.C.) 1854-1972, 1917-01-28
Measuring the Fuel Content of Coal With Teaspoon

ture of one kilogram of water one de-
gree c.
While the same principle has been
used in other laboratories, no device
like that of the bureau of mines has
been constructed elsewhere. although
some of the great institutions have re-
Gently been examining this with view
to making one like it. 1t is called a
calorimeter. or heat measure. On en-
tering the room where it is. the first
thing one sees is a tank about ten feet
long. lighted from within by electric
bulbs. filled with water actively agi-
tated. and within 1t what looks like
half dozen small ice cream freezers
whose covers just reach the surface.
From A steel frame over the tank rods
revolving appear to enter the freezers.
Electric wires attached to glass tubes
hang about in an interesting way and
connect with the cans, for, of course,
they are not really freezers. Nothing
would freeze in that water, for most all
this fuss is for the express purpose Of
keeping the water at constant tenn
perature-S6 degrees +.
When the freezer. which, is nothing but
heavy copper can with a non-leakable
cover. is opened it is found to contain a
number of things. There is definite
quantity about four pounds) of water. a
little propeller blade. which is run by the
vertical revolving rod. TO keep that water
in constant motion. the thermometer at
tached to the electric wire and an cleo
trio thermometer connection, by which
the temperature of the water in tho can
is recorded.
But the interesting thing in it is called
a bomb, hollow steel cylinder with
walls thick and strong that they can
stand an internal pressure of 500 pounds
to the inch. To prepare this bomb for
immersion in the pail. the laboratory as
sistant. having opened it, places in tho
bottom a little cup containing exactly n
gram of sixty-mesh undried coal: across
and through it is a delicate fuse wire
connected between two posts. The top OF
the bomb is then screwed down with all
the strength of a good man on the END OF
a five-foot bar Pure oxygen, more than
enough to insure the combustion OF the
COAL is then forced into the bomb until
there is a pressure of 400 pounds.
The bomb thus charged is carefully
dropped into the ice cream freezer can.
the cover is clamped down, the Their
1nometer falls into the water content OF
the can and an electric spark is flashed
through the little wire in the coal dust.
There is an instant glow and then the
oxygen produces a combustion within tho
bomb which develops the last iota or heat
in the gram of coal, leaving within moth
ing tangible but the ash
But the intense heat of that little fre
passes through the walls of the bomb
into the water of the can. Calculations
have established the corrections to be
made for the heat retained in the bomb
the tank. The result of the readings
which are made by telescope of the
thermometer is the ascertainment OF
the exact amount of heat given out by
the gram of coal taken from the SAM
pie under test; and from that CAL
culation of the number of British Their
NAL units to the ton of coal under test
is simple.
The results of the separate tests for
moisture, ash, fixed carbon, volatile
matter and thermal units are returned
to the desk. Each bears the serial
number of the sample. and the results
are placed with the data furnished with
the sample The whole is collected into
certificate, which shows with scien-
tic accuracy the result of each test.
Coal, to give the best results, should
be low in moisture, low in ash. high in
fixed carbon. but need not he extremely
rich in volatile matter. Such coal will
/ necessarily be high in thermal units.
Unless coal be low in ash and moisture
it will not give first-rate results. even
if high in thermal qualities, unless
burned in suitable furnace.
The quantity of coal used in the test
may seem small, but the result is big.
1t has brought a saving of many hun
dreds of thousands of dollars, not yet
tabulated, to the government.