Martinsburg herald. [volume] (Martinsburg, W. Va.) 1881-1920, 1902-11-22
HOW COAL WAS FORMED.


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Some interesting ana mysterious
points in the history Of coal formation
are discussed by DR.. j. Il. Hoffmann.
Of Berlin. in the Zetschrift fur Ange-
wandte Chemie Although authorities
are agreed that coal is fossiled vegeta-
ton, the details OF the process bv
which it came to be what it is are by
no means clear. DR.. Hoffman believes
that spontaneous combustion was an
important factor. According to con-
tributor to London engineering, who
discusses DR.. Hoffman's paper the
popular view of the formation of coal
may be summarized as follows: Certain
plants or trees grow in morasses; they
decay and sink, more plants grow on
the first laver, and sink in their turn.
The weighted down residue decompose
through the influence of microbes,
with the generation Of methane and
carbonic acid and when the decom-
posed mass is afterward exposed TO
high pressure we find, according 10
the age of the deposit, peat, Ignite,
coal or anthracite. Graphite does not
appear to have the same genesis as
coal. He goes on to say
Some weak points Of tine popular
view are pretty apparent II time and
pressure be the main factors which de-
eide the oliaractee o. the cosl. then we
sbould find .nt eite "a lie oldest
geologic ! ofae lions aad peat in tie
Deyonlau, and we know Historically
OF Tie eFiange Of "a so nbee ilto lfa-
uite, While we have no EXAMPLES Of
peat passing into coal Further am
thracite forming the bottom LAYER,
should contain most ashes. aud. so far
as actual experiments can teach us,
the verv highest pressures of 20, 600 at
mospheres 90 not cause vegetable fl
Der to become coal. =
Dr. Hoffman raises some other
points He would distinguish three
periods i'll the formation of coal.
First, period OF microbe activity. a
fermentation, so to say; then a period
of decay, aud, finally, the carboniza-
ton period proper. Mere heat does not
change wood into cool, though we can
| finally obtain a substance like anthra
cite when we gradually raise the tenn
perature above 400 degrees. G. Hoff
man draws attention to the sponta-
neous heating, and ignition often OBJ
Sc we'd III vegetable products, and he
stodies the ID oblem the mechanically.
Hay is very apt TO heat in warm,
damp condition and to burst into
flames when air gains access. Wet fax
is notori ously dauge gous, aud so are
oiled rags.
A mill containing grain and -four
was barned down in Berlin some years
ago; the fire was ascribed to sDonta-
neous combustion. and IN some big
Jumps efismuoldering grain which had
been thrown into the livet Hoffman
discovered LAYERS resembling Ignite,
coal aud anthracite? IN this sequence.
In all these cases moisture faYors the
combustion o. the fungoas growth
starting it. With coal this is not so,
because there is no o organized fiber ami
no fungous growth. The writer in
Engineering says in concluding his re-
view of the German article:
Geologically we have reason to be-
lieve that the formation of the coal
beds was followed by violent titanic
commissions, during which heat and
pressure may have coacted. Bv spon-
taneous combustion some seam would
become charred the heat would be
communicated to another seam and so
on, so that coal beds of considerable
extent would be Produced. But Hoff-
man himself sees that we do not un-
derstand. on these lines, how it is that
coal beds consist OF fal ~ uniform coal
coal, anyhow. not lignite--all
through down to their extreme veins
We do not arrive at any final conclo-
sions as to the genesis OF coal. there.
fore, aud the chief interest of Dr.
Hoffmann's pane lies in the fact that
he draws attention 10 the influence of
! spontaneous combustion. -
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