The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1873-08-02

rs not soluable in water until it combines with
an additional proportion Of carbonic acid, by
which it's transformed into the bioarbonate Of
lime. In this way the process of excavation
was conducted, until Communications were
established with running water, by which the
mechanical agency of that fluid was made to
assist the chemical. The little inches and re.
cesses which are observed in various parts of
the Cave, and which seem to have been chise.
ed out and polished by artificial means, were
formed IN this manner for when these points
are closely examined crevice will BE- observed
at the top or back Of them, through which
water issued at the time of their formation,
but which has been partially closed by crys.
tails OF carbonate OF lime, or gypsum. AT the
time these inches were forming, water flowed
through the avenues in which they are found.
Examples of the action we have beea describ.
ing, may be seen in Sparks Avenue, leading
to the Mammoth Dome.
The grooves which are observed in rock
over which water is, or has been flowing, are
also formed by the solvent action of water
containing carbonic acid for in all such in
stances, the water has no solid matter in sus-
pension. Examples of this kind of action
may be seen in operation in Mammoth and
Gorin's Domcs and evidences of its former
action may be observed in Luey's Dome.
what are termed the pigeon.hOles, in the
Main Cave, are cut out of the solid rock in
the same manner.
When water, holding the bicarbonate Of
lime in solution, drops slowly from the cell.
ing, by which tits exposed to the air sufficient
ly long to allow of the escape of one equiva-
lent of carbonic acid gas, the lime is deposited
m the form of.the proto- carbonate OF lime. If
the deposit occur in such n manner that the
accumulation takes place from above, down
ward, IN the form of an icicle, it constitutes
what is termed stdldctite; but if it accumu-
late from below, upward, it is called daldg-
mite. Stalactites and stalagmites frequently
meet in the centre, and become cemented, by
which column of support is formed. Many
instances Of this kindNre to be found in Goth.
ic Arcade and Fairy Grotto.
II the limestone which forms the stalaetite
is perfectly pure, it will be white or semi
transparent; if it contain oxyd of iron, it
will be of a red or yellowish color. When n
stalactite is black, it contains the black oxyd
OF iron. The stalagmitc cinders in Vplcan's
Smithy, and the grapes in Marthas Vineyard
are colored with black oxyd Of iron.
Another agency which contributes in part to
change the appearance of the Cave, is the
efilorescence OF the sulphate Of soda or Glau-
ber.salts, and the capitalization of sulphate
of lime or plaster of Paris
The sulphate of lime, which is known UNI
der the names of gypsum, plaster of Paris,
selenite, alabaster, etc, eXerts n much greater
influence in dsintegrating the rock than the
sulphate of soda. The avenues in which gyp-
sum occurs are perfectly dry; difieringln that
respect from those which contain stalsctites.
When rosettes Of alabaster are formed in the
same avenue with stalactites, the water which
formed the latter has for ages ceased TO flow,
or they are situated far apart, as the former
cannot form in II damp atmosphere, The
force exerted by gypsum in the act Of crystal.
izing, is about equal to that of water when
freezing, for when it crystalizes between ledg.
es, or strata of rock, they are fractured in
every direction, az instanced in Pensacola
Avenue and Rhoda Arcade.
The formation of inter is due, in part, to
the decomposition of remains of bats and
other animals, but it must not be forgotten
that limestone rocks are never entirely desti-
tute of nitrihnble matter. The nitric acid
which enters into its composition NAV. in some
measure, be derived from the atmosphere.
The kind of inter that is found in the Cave is
nitrate of lime, which, when reacted upon by
the carbonate of potash, is transformed into
nitrate OF potash or common saltpeter. This
was the course pursued By the saltpeter mi
ners, when that substance was manufactured
in the Cave in lSl2-l4. The nitrate Of lime
is found in dryer parts Of the Cave, but is not
discoyerable till the earth which contains it is
lixiviated.
The mechanical agencies concerned in the
excavation of the Mammoth Cave are trihing
when compared to the chemical.
They are instanced in the transportation of
gravel, sand, and clay, from one part of the
Cave to another, and in the abraded appear
ance presented by the rock composing certain
avenues. Thus, it is possible to tell the direc-
ton which the water ran in most of the
avenues, and the rapidity Of its motion, by
observing the points ut which gravel, sand,
and clay are deposited, and the order in
which they come. For example, the points at
which gravel is deposited indicate a rapid
current where sand is found the movement
was almost or quite stationary.
At one time water rushed with great force
through Fat Mans Misery, for in Great Relief,
which is just beyond, washed gravel occurs !;
still farther sand is found, which is succeeded
by clay: showing that the current was in the
direction of Echo River. Before the mechani-
cal agency could have exerted any appreciable
influence, the chemical must have been in
operation thousands of ages.
The loose rocks that IRE scattered on the
floor of many of the avenues, have fallen from
the walls and ceiling, but in many instances
the points from which they were detached are
indistinct, from the fact that the rugged sur
face from which they have fallen is either
smoothed by the action Of water, or covered
by crystals of the carbonate or sulphate OF
lime. In those parts of the Cave where no
rocks have fallen, the floor presents the APP
pearance of the bed of river, and is covered
with gravel, sand, or clay, according to the
rapidity ofthe flow of water at the time of the
deposit. No rocks have fallen since the dis
covery ofthe Cave.
There is an interesting relation subsisting
between Mammoth Cave and Green River.
Thus, there can be no doubt but that Green
River has cut out the bed or channel through
which it runs, for on ascending its banks on
either side for distance of not less than three
hundred feet, plain is reached, which is not
succeeded by a valley; establishing conclu-
sively that it has worn its bed to its present
level by the mechanical and chemical agency
of water, and that the avenues of the Cave
were cut through with nearly equal pace :
those near the surface of the earth being
formed first, and the others in regular order
from above downward the avenues through
which Echo and Roaring rivers run being the
lowest and last formed. Both of these rivers
are on level with Green River, with which
there is subterraneous communication. As
Green River continues to deepen the valley
through which it runs, the avenues of the
Cave will continue to descend, until the springs
which supply Echo and Roaring rivers cease
to flow, when the avenues through which they
run will become as dry as Marion's Avenue,
which at an early period in the history of the
Cave, contained the most beautiful subterra-
mean river in the world.
After leaving small archway near the
mouth of the Cave, the sides OF which are
walled with rock, which the salpeter manufac.
turers obtained from the floor ut this point,
and which is called the Narrows, the visitor
enters the Main Cave, which is six miles in
length, and which varies from forty to one
hundred feet in hight, and from sixty to three
hundred feet in width.
The Rotunda is entered on leaving the Mar.
rows The ceiling is about one hundred feet
high, and its greatest diameter one hundred
and seyenty.fve feet
The floor is strewn with the remains of watts,
water-pipes, and other materials used by the
salpeter miners, in 1872. The wood Of which
they are made shows no indications of decay.