Evening star. [volume] (Washington, D.C.) 1854-1972, 1893-01-21

'%I AHEE was not SO very long
<1S fsfES ago that fossil stores of
VIZ m as fuel were first drawn
upon for the use of man
kind. That they cannot last forever is q pain
full fact to contemplate. Only a few centuries
from now, as it is reckoned, the coal mines of
the world will be practically exhausted. Hap
ply, the present generation will not be called
on to solve the melancholy problem thus pre-
sented.
YEARS AND YEARS AGO.
As the reluctant householder shovels its regu-
lar stint of food into the greedy NAV of the
ogre in the cellar, otherwise known as the fur
mace, it is marvellous thing for him to con-
slder that he is keeping his dwelling warm By
the heat OF the suns rays which fell upon the
earth millions of years ago. The solar orb of
that vanished epoch bigger than it is today and
tropical vegetation of a wonderful luxuriance.
piants OF strange kinds grew up richly from the
clayey soil and formed dense jungles in the vast
marshes which covered large areas of the sur
face OF this planet. Ferns. moses and the
leaves, branches and trunks of trees tell and de-
eayed where they grew, only to make the soil
more fertile aud the next growth richer and
more luxuriart. Year after year. century after
century. this process of growth and decay went
on, until the beds of vegetable matter thus de-
pOSIteu nau reached great thickness.
But the earth body WAS still shrinking, and
in consequence her crust at times contracted
and fell in. When it did 80 the land sank
throughout vast areas these beds of vegetable
matter went down and over the great marshes
the water swept again. bringing drift Of vege-
tation from higher levels to add to that already
| buried. Then over these deposits the sand and
mud and gravel were laid up anew, and the
clayey soil from which the next rich growth
would spring was spread out on the surface.
This process was repeated again and again-as
often. indeed. az seams of coal in any coal bed.
Thus the conditions for the formation of coal
were made complete, atmospheric air being en-
tirely excluded while the vegetable beds under
went the processes of decomposition. These pro-
cesses went on under the water of the ocean,
under the sands of the shore, under the new
deposits OF succeeding ages, Transforming the
wood OF the carboniferous era into the coal of
today.
NATURE rs STILL MAKING COAL,
though, unfortunately, not at q rate ANYTHING
like fast enough to make up for the consump-
ton of this product. The processes may be
watched from beginning to end For this pur-
pose one must first go to peat bed which is
simply an accumulation of the remains of plants
that grew and decayed on the spot where they
are now found. When the upper layer of this
material is removed one finds peat with SO to &c
per cent OF carbon, and the deeper one goes the
better in quality it gets. 1t may be cut out in
| blocks with sharp spades, the water NAV be
pressed from the blocks, and they may be
stacked up. covered and dried and used for
fuel. There is certain kind of moss called
| "sphaSnnm. which in large part makes up the
| reproducing vegetation. Its roots die annu-
ally, but from the living top new roots are sent
out each year. The workmen who dig peat I'M
derstand that if this surface is DESTROYED the
| growth Of the bed must stop; SO commonly they
| removed the sod carefully replacing il after
ont 81 tim, of
! Is little doubt that il these beds of peat could
| lie undisturbed and covered over through many
| ages they would take on all the characteristics
| OF mineral coal.
| THE VEGETABLE STRUCTURE OF COAL.
| The substance of coal has been 80 compressed
that the forms of the plants composing it cannot
usually be seen. But when piece Of it is made
go thin that it will transmit light, and is then
subjected to powerful microscope, it's vegeta-
bic structure may readily be distinguished.
| immediately under every separate seam of coal
there Is a stratum Of what is known as fire CLAW
! This stratum Is always present and contains in
| great abundance the fossil impressions of roots
and stems and twigs, showing that it was once
the soil from which vegetation grew luxuri-
! antly. 1t ls common also TO find fossil tree
stems ly ing mashed fiat between the layers of
black slate which form the roofs of coal mines "a
| well as the impressions of the leaves. nuts and
seeds which fell from these trees while they
| were living In some beds of camel coal whole
| trees have been found with roots, branches.
leaves and seeds complete. and all converted
| into the same quality of coal as that by which
| they were surrounded.
BrrUMINoUs AND ANTHRACITE.
biologists are Of the opinion that bituminous
and anthracite Goals were formed during the
same period and under like conditions. Origin
| ally they were all bituminous but during the
violent contortions and upheavals of the earth 6
| crust at the close OF the carboniferous age the
| bituminous Goals involved in that disturbance
were changed by heat and pressure, and the
| consequent expulsion Of volatile matter from
bituminous to Anthracite. Camel coal is a
| variety of bituminous coal which burns
with great freedom. the flame OF it afford
ing considerable light 1t was called candle
| coal by the English people who first used it,
g. a., 1t OFTEN served as substitute for candles.
| The name became corrupted to camel and
has SO remained. 1t is more COMPACT than
ordinary bituminous coal and it can be wrought
| in lathe and polished certain variety OF il
found in Yorkshire. England, is manufactured
into kind OF jewelry known as '.jet."
PENNSYLVANIA DURING THE coAL-FoRM1NG EPOCH
| DIR. Homer Greene gives an interesting de-
scription Of the climate of PENNSYLVANIA
during the conforming epoch. The most
remarkable features Of the vegetation of
that period were the size and abundance of it's
| pIahts frees OF that time whose trunks were
from one to three fe"t in diameter and which
| grew to height Of from forty to a hundred
feet are represented at the present day by SIM
liar species whose stems only fraction of
| an inch in diameter and but one or two feet
high. But at that time all conditions were
favorable for rapid and enormous vegetable
growth. The air was laden with carbon, which
is the principal food of plants-so laden indeed,
that man could not have lived in it. The great
| humidity Of the atmosphere was another ele-
ment favorable to growth. Vegetation never
| lacked an abundance Of moisture either at root
or leaf. Then. too, the climate was universally
warm. Over the entire surface of the earth
| the heat was greater than it is today at the
| torrid zone. With all these circumstances in
its favor vegetation could not help fourishing.
The fossil impressions of more than 500 differ
emit species Of plants that grew at that time
| have been found in the coal beds.
| FOSSIL BEMAIxs OF FERNS.
The most abundant Of the plants Of the coal
forming era were the ferns. Their fossil re-
mains are found in great profusion and variety
in most Of the rocks of the coal-bearing strata.
There was also the plant known as the .'tree
fern" which attained q height Of twenty or
thirty feet and carried q single great tuft Of
leaves at its top. Next in importance to the
/ Ferns were gigantic moses resembling in kind
the low "club" moses Of the present. but vastly
magnifed. They doubtless contributed the
greatest proportion Of woody material to the
4 cQmpositiOn of coal They vera forest traS>a