The Republican. [volume] (Oakland, Md.) 1877-current, 1902-12-25
HOW COAL WAS FORMED.
Consideration of One of the Great Process
es of Nature-DetaiIs of the Fossil
ization of Coal.

es of Nature-DetaiIs of the Fossil
| ization of Coal.
Some interesting and mysterious
points in the history of coal forma-
ton are discussed by j. F. Hoffman,
of Berlin, in the ''Zeitchrift fur Ange-
wandte Chemie." Although authori-
ties are agreed that coal is fossilized
vegetation, the details of the process
| by which it came to be what it is are
by no means clear, says the Literary
! Digest. DR.. Hoffman believes that
spontaneous combustion was an i'm
portant factor. According to a con-
tributor to London Engineering, who
discusses DR.. Hoffman's paper, the
popular view of the formation of coal
may be summarized as follows: Ger
tain plants or trees grow in morasses;
they decay and sink in their turn.
| The weighted down residue decom-
poses through the influence of mi
crobes, with the generation of me-
thane and carbonic acid; and when
the decomposed mass is afterward ex-
posed to high pressure we find, accord
ing to 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 the popular
view are pretty apparent. If time and
/ ha 1,o 4. II,
decide the character of the coal, then
we should find anthracite in the old
est geological formations and peat in
/ the most recent. But Ignite occurs
in the Devonian, and we know his
/ toTically of the change of mine timber
/ into Ignite, while we have no exam
pies OF reat passing into coal. Fur
ther, anthracite forming the bottom
layer, should contain most ashes and,
so far as actual experiments can teach
us, the very highest pressures of 90
900 atmospheres do not cause vegeta-
BILE fiber to become coal"
! DR.. Hoffman raises some other
points. He would distinguish three
| periods of the formation of coal. First
a period Of microbe activity, fer
! mentation, so to say; then period of
decay, and, finally, the carbonization
period proper. Mere heat does not
change wood into coal, though we
can finally find substance like an
thracite when we gradually raise the
! temperature above 400 degrees. G.
Hoffman draws attention to the spon-
taneous heating and ignition often
observed in vegetable products, and
he studies the problem thermo-chem-
ically. Hay is very apt to heat in
warm, damp condition and burst into
flames when air gains access. Wet
flax is VIGOROUSLY dangerous, and so
are oiled rags.
A mill containing grain and flour
was burned down in Berlin some
wears ago; the fire was ascribed to
spontaneous combustion, and in some
big Jumps of smouldering grain which
had been thrown into the river Hoff-
mann discovered layers resembling
| Ignite, coal and anthracite, in this
| sequence. In all these cases moisture
favors the combustion or the flung
GUS growth starting it. With coal
this is not SO, because there is no Or
gained fiber and no fungous growth.
The writer in Engineering says in
concluding his review of the German
article:
Geographically we have reason to
! believe that the formation of the coal
beds was followed by violent titanici
commissions. during which heat and
pressure may be coacted.
By spontaneous 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 produc-
ed. But Hoffman himself sees that
we do not understand, on these lines,
how it is that coal beds cannot ignite
all through down to their extreme
veins. We do not arrive at any final
conclusion as to the genesis of coal,
therefore, and the chief interest of
DIR. Hoffmann's paper lies in the fact
that he draws attention to the influ-
ence of spontaneous combustion.
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| DaVmentS ADnly TO Ju1iuS G. Rem