Evening star. [volume] (Washington, D.C.) 1854-1972, 1917-01-28

IN HE bureau of mines. from half
teaspoonful of powdered coal
tells the government how much
q heat there is in the bargeload
of black diamonds delivered at the
wharves of some federal station. 1t
burns in it's own way another pinch
of the black powder and tells its in
spectors that the delivery is high or
low in worthless moisture, baleful ash,
rich carbon or in infammable volatile
matter
1t. gives buyer and> seller square
deal by adding bonus for coal that
will heat and fixing a penalty on coal
which is below the standard, without
the loss to both parties of a rejection.
1t enables the producer of low-grade
coal to find market for it on such a
basis as it's quality deserves.
There are number of commercial
laboratories where big purchasers and
progressive producers can have their
coal tested, but the laboratory or the
bureau of mines, which makes tests OF
the coal used by the federal govern
ment and by some states and munic-
qualities (by law it cannot make tests
for individually takes the lead in TINS
unique work Its report determines the
cry. the price per thermal unit having
been agreed upon.
For instance coal-about 100 tons
is needed for the federal buildings in
New Orleans-the custom house, post
office, etc This is to be paid for ac-
cording to moisture. ash. volatile mat
ter and the thermal units it contains.
Thesce are determined, according to the
contract, either on the coal as re-
ceived or on the basis of dry coal
that is. coal as delivered less the mols-
ture, which adds weight without value.
The first thing is to secure sample
of the coal as delivered, which is done
by taking 1000 pounds of coal from all
parts of the delivery. breaking it to
one-inch size. coming 1t. spreading 1t
out in long pile a shovelful at time,
halving it by throwing one shovelful
into the discard and the next into
pile. and repeating this operation with
some variations until there are lett ten
hounds of finely crushed coal. Half of
this is retained and the other half sent
by mail in galvanized containers to the
bureau of mines.
wrapped about the can, which has
serial number is a sheet giving the
details of the delivery from which the
sample was taken. Upon its receipt at
the laboratory, this sheet is detained
at the desk and the sample is known
only by it's laboratory number to those
who conduct the tests.
The first test is for moisture. sam
pie is chewed up in chipmunk- jaw
breaker and then crushed in roll
.crusher until it will pass through
twenty-inch mesh-that is. sieve
whose meshes are one-twentieth of an
inch square.
Five grams are weighed into tiny
crucible and placed for an hour and a
half with dozens of similar test charges
in an oven heated to los degrees cent?
grade (221 degrees FahrenheiO This
temperature. which is SO low that none
of the volatile matter is driven off, is
kept steady by means of a mixture of
glycerine and water, which is kept con-
slant at los degrees, Superheated air.
which, lest it contain grease or other
matter, is purified by passing through
sulphuric acid, circulates through the
ovens and drives off the moisture lib
Grated by the heat.
After standingf in a desictor-a por-
celain tablet above sulphuric acid.
which absorbs moisture-the sample Is
weighed and from the loss the per
centage of moisture in the entire lot of
coal Is directly determined. This Is
checked by second run made in the
same way from the same sample.
This operation is further checked in