Evening star., 1914-07-26

10 De used. opens the cars dumping gates
ana the fifty tons shoot into the vessel's
hoid in a great deal less than that many
seconds. He not only drops il into the
nesseiS mold. hut he distributes il with
little waste and little brcakage iron, one
point to another by moving the chute
ABOUT 1t means that the men in the
noid can level the coal off in easy time
10 get ready for the next carloa6 When
this car has performed its work it speeds
rapidly away and returns upon another
track to await ITS next load.
Although there arc thousands OF tons
OF hard coal shipped through Uncle Sa.u's
coal ports to various parts of the world.
the demand for tse soft coal for steamine
use causes the rush. Most vessels car
ryins such coal in cargo take out from
..'Nhp TO iNn tons. and they want their
bunkers filled to get away in the shortest
possible time. 1t takes only abou. one
hour. and fifteen minutes to coal the
smaller vessels. and recently a vessel
!ihs '.2'n tons was loaded in three
houfs. an almost phenomenal soeed
The cause of fire in the interior of great
quantities of coal has been much dis
cussed question. Scientists agree that il
is que to spontaneous combustion, but a.
10 ITS action they do not agree. The mos
accepted of the theories however. is thar
Que TO molecular action.
FOR instance. when coal is piled I'd in n
great heap and subject to the eefect or
the suns rays as it would be in a closed
bin or in the hold of a shin. there !. br,
httie circulation OF air. In time the coaI
becomes heated and the be., .xo;. a..
molecules into rapid vibration Wi,b ,o
iieuia'ioh OF air in the center of the pile
'"e 'no!eeular vibration becomes NOR.
rapid thus causing intense friction and
the generation OF still greater hear
men the point OF combustion is reached
the hner particles begin to burn and
nhaiis the whole interior of the nil. =.
affected.
III hiooefn methods of storing and shin
pihg coal this emergency is partially nro-
'ided against by inserting a system or
pipes through the coal pack in the hold
OF tne vessel. Being connected with tba
deck' they cause circulation Of air
t+ Uushout the interior Of the coal pack,
heeping the temperature down to a noint
Hlucn below that Of combustion
IN these days when such great uuanti
..es OF coal are shipped at one time pre-
CAUTIONS are necessary. Fire in a coal
pack means the hardest Kind Of a 6oht
10 food 4 hold filled with burning coal ix
an exceedingly dangerous operation. be-
cause IT means the generation OF gas thar
would cause an explosion big enough to
blow the vessel to pieces Steaminr tha
hold and causing enough ventilation to
larry OF the gas is mostly resorted to.
but even that has its drawbacks The
moment ventilation is provided the coal
fire takes advantage of the draueht and
burns more fercely.
Uncle Sam assists this work in still
another way. All of the coal that il
shipped must be graded. and to secure
these grades the different coal mines
must be analyzed. Samples of each min
ing are therefore collected and sent to
the laboratory of the Bureau of Mines,
where their constituent parts are
out and listed. These samples
are then forwarded to the coal ports.
where an inspector sees that each ship
nent agrees with the samples.