If the earth were transparent as the atmosphere we should see many
things of wonderful interest and beauty beneath its surface. If we could
see the mineral gems that lie beneath the earth’s surface they would
rival in beauty the jeweled firmament above us. We should also see
rivers and rivulets of crystal clearness and lakes of broad expanse. I
can almost hear my young readers saying, “I wish we could look beneath
the surface of the earth and see the wonderful and beautiful things it
contains, just as we look up to the stars, or out of the window upon a
landscape.” But let me remind them that nature has been very generous in
furnishing rare and wonderful things for them to study and admire to
which they can have easy access almost every day. The longest life is
too short to study and admire more than a few of the things we may see
upon the surface of the earth. Nature has opened a few doors so that we
may walk in, study and admire the work she is carrying on in the
darkness where the light of the sun never penetrates. Nature makes a
free use of sunlight to perfect her most beautiful work upon the surface
of the earth, but her most delicate and beautiful work beneath the
surface of the earth is wrought by other agencies. Caves have been
entered and explored by natural openings, and springs and rivers gush
out at the surface of the earth, telling us plainly that they are fed by
subterranean fountains and lakes.
Following the order of our topic, let us see what we can find out about
underground streams and lakes, and why we know they exist when we seldom
see them. We know that large rivers after flowing miles upon the surface
of the earth suddenly drop into subterranean channels and reappear after
running miles underground. Springs which are always flowing must be
constantly fed from some source beneath the surface of the earth. In
boring wells the augers, after going down to various depths, suddenly
drop several feet, showing that they have reached a cavity in the earth
or a fountain of water; if the water gushes up it is evident a fountain
has been struck.
Where does the water come from to fill the underground lakes and
reservoirs and keep the rivers constantly flowing? Geologists tell us
that all the land surface of the earth was for vast ages under water;
that the great oceans that now roll between the continents once covered
them entirely, but after long ages mighty internal forces of the earth
raised them above the ocean’s level. For a long time after the hills and
mountains were raised above the surface of the ocean, where the valleys
and prairies now are there were lakes and inland seas. The water in
these lakes and seas did not all evaporate or find its way to the ocean
by the rivers that flowed from them. Deep down into the earth much of it
found its way, along the fissures and porous strata, until it reached
some impervious stratum, as clay or granite. But as this first
underground supply would in time become exhausted, by flowing into the
ocean through the rivers they fed, nature has made further provision for
keeping up the supply. Everywhere upon the surface of the earth where
there is water or moisture evaporation is going on. The sun raises
enormous quantities of water in the form of vapor, which forms clouds
and descends in rain. A part of this water is soon restored to the sea
by the rivers, but by far the largest portion penetrates the earth’s
surface, as water would penetrate cloth or a sponge when poured upon it.
Rain penetrating the earth goes down until it comes to some substance
that it cannot penetrate. Then, in trying to find its level, it will
distribute itself just as it does upon the surface of the earth. It will
find its way into cavities, large and small, or following some
underground channel or stratum, it may burst forth a clear and sparkling
spring, or it may flow on a rivulet, or river, and perhaps enter into a
great subterranean lake. The underground fountain or lake that keeps an
artesian well spouting from year to year may be fed by a stream or lake
in the heart of some distant mountain. Some artesian wells cease to flow
after a while, showing that the fountain that supplies them is at least
partially exhausted. We do not know to what depth water penetrates the
earth. Artesian wells have been bored in recent years to the depth of
four thousand feet. The temperature of springs and artesian wells is
regulated by the temperature of the strata through which the water
percolates. The geysers of Iceland send up enormous jets of hot water in
the midst of Arctic cold.
[Illustration: OLD FAITHFUL GEYSER.
(Yellowstone National Park).
PHOTOGRAPH BY F. J. HAYNES, ST. PAUL.]
The earth is nature’s great filter, cleansing and purifying the water
from the impurities of the soil. As it passes through strata of gravel
or clay, it becomes pure and wholesome to drink. Sometimes water passes
through a stratum containing sulphur, iron or magnesia, and so we have
mineral wells and springs. There is in Brown County, Illinois, an iron,
a sulphur, and a magnesia spring within a few feet of each other.
Having considered underground streams and lakes, artesian wells, and
geysers in a general way, we will now proceed to notice some of the most
remarkable of each. Of underground lakes we know but little. We cannot
enter them as we do a cave, and if we could now and then find an
entrance to them, we should find little room between their surface and
the strata above it for navigation. We infer their existence, because
they are necessary to supply many underground rivers and smaller streams
that come to the surface and discharge their waters into the ocean.
Another proof of their existence is found in the large areas of country
where deep water is struck at a uniform depth measuring from the ocean
level. The bogs of Ireland are floating upon underground lakes.
Springs are gems of the first water, as the dealer in precious stones
would say of a perfect diamond. They do not impress us with their size
so much as the way they minister to our comfort. But few wells equal
them in the variety and purity of their waters. I remember a spring back
in New England, which burst forth from a bed of gravel at the side of a
hill with such force that it seemed to fairly boil, though icy cold and
clear as crystal. So violent was the ebullition that the gravel and
pebbles were continually thrown to the surface. Then it ran leaping,
gurgling and sparkling down a steep declivity, and was joined on the way
by rivulets from three smaller springs, so that when it reached the
level of the valley it became a quiet, well-behaved brook, the home of
the speckled trout. In places where it spread out over a gravelly bed
the birds would light upon the stones and sip the water, and fly away
singing joyous notes for so exquisite a luxury. A half mile from its
source this brook became quite broad and deep. It ran through a pasture,
and cattle came and slaked their thirst.
Hot springs are numerous in all parts of the world. The water of most
hot springs has decided mineral properties, for the reason that hot
water passing through mineral strata will dissolve more of the mineral
substance than cold water. Many hot springs are great resorts for
invalids because of their curative properties. The famous Silver Spring
in Florida has the dimensions of a small lake, and boats sail over it,
and a small river continually flows from it. The inhabitants of Chaudes
Aigues, France, use the water of the hot springs to cook their food, to
wash their clothes, and warm their houses. The heat from these springs
is worth about $30 per day, as it is equal to the heat produced by five
tons of coal.
Few things in nature are more beautiful and impressive than a river
bursting from the hillside, its clear water sparkling in the sunlight,
seeming joyous at being free from its captivity. Among the most
celebrated and beautiful of subterranean rivers is the Sorgues of
Dauclûse, in France. It flows for miles through a cave, and discharges
thirty cubic yards per second. Soon after it issues from the cave it
divides into numerous irrigating channels, and spreads fertility over an
area of more than eighty square miles. Echo River in Mammoth Cave is
navigated by boats for nearly a mile, and in some places is two hundred
feet wide. The Poik River in Austria flows through the famous cave of
Planina. The cave can only be explored by a boat. Professor Schmidt,
with three companions, navigated the river for more than a mile. Along
the continental shores many outlets of subterranean rivers may be seen.
In 1857 all that part of the sea adjacent to the southern point of
Florida received an immense eruption of fresh water. Intelligent
observers estimated that for more than a month this remarkable
inundation of a subterranean river discharged as much water as the
Mississippi, and spread all over the strait, thirty-one miles wide, that
separates Key West from the mainland of Florida.
Among the wonders of Yellowstone Park the geysers are the most noted.
One of them is called Old Faithful, because he always spouts on time. He
gives a grand exhibition every hour, whether he has an audience or not.
He spouts, and sputters, and hisses and throws a huge column of hot
water into the air, and then quiets down and gets ready for another
performance. Another geyser in Yellowstone Park is called the Beehive,
being cone-shaped like the old-fashioned beehive. It throws up a column
of water more than two hundred feet. Castle Geyser is another that
throws up a larger column of hot water than either of the above. The
falling water has built up a huge crater that resembles a castle, hence
its name. But the largest geyser in Yellowstone Park is called the
Giantess. The well or orifice through which it sends up its column of
water is more than twenty feet in diameter. The steam arises after the
water has been ejected. A body of water more than twenty feet in
diameter ascends in one gigantic column to the height of ninety feet.
Then from the apex of this column five jets shoot up, radiating slightly
from each other to the height of two hundred and fifty feet from the
ground. The earth trembles under the descending deluge of this vast
column of water, a thousand hissing sounds are heard in the air,
rainbows encircle the summits of the jets with a halo of celestial
glory. The falling water plows up and bears away the shelly strata, and
a seething flood pours down the slope into the river. It is the grandest
and most terrible fountain in the world. Visitors have to wait hours and
sometimes days before the geyser will entertain them with an exhibition
of its power and beauty.
Commander Ford, of the British Navy, says that one of the geysers of
Iceland, called the Stroker, can be excited to action by throwing stones
and turf down into the pit, and that the geyser resents the insult by
throwing them up. He found that it usually took about forty minutes
after throwing in the stones before they were thrown up. It occurred to
him that he might send his dinner down and have it sent back to him well
cooked. So he wrapped a leg of mutton and a fowl in a cloth and threw
them into the boiling caldron, where he would never see them again
unless they were thrown up. After waiting the usual forty minutes he
began to regret his venture, but the geyser was only seven minutes
behind time, and up came his leg of mutton and fowl done to a turn.
Aside from the beauty of the columns of water, vapor and steam geysers
send up, the waters are all the time depositing carbonate of lime and
silica, and building up craters of many interesting forms.
The principle on which artesian wells act is very simple and can be
understood by any schoolboy. Though this principle is very simple, there
are so many varying conditions that many expensive failures result.
Millions of dollars have been spent to get pure wells of flowing water,
with nothing to show but holes in the ground or a flow of useless
mineral water, but sometimes a good quality of mineral water is
obtained. At Henry, Illinois, a flowing well of sulphur water is highly
valued by the people, who come many miles to obtain it, while a few
miles north of Henry, at Bureau Junction, there is a well of soda water
which is very palatable.
Some of the best authorities say that only flowing wells should be
called artesian. I will refer to a few of the many flowing wells. The
hot springs in many parts of the world are natural artesian wells, the
water being forced up from great depths. It is estimated that there are
more than fifty thousand wells east of the Mississippi River from one to
two thousand feet in depth, drilled to obtain petroleum oil or the
inflammable gas which accompanies it. These are as strictly artesian
wells as those that send up water.
Among the most noted artesian wells is the one at Grenelle, in Paris. In
boring this well, after going down one thousand seven hundred and
ninety-seven feet and passing through a stratum of rock over a
subterranean fountain, the drill suddenly fell fourteen feet and the
water soon rose above the surface. The temperature of the water coming
from this well is eighty-two degrees, Fahrenheit. It is conducted by
pipes to the hospital in the town, for heating purposes. The bore in
most artesian wells is from three to six inches in diameter, but the one
at Passy, near Paris, is twenty-eight inches in diameter and one
thousand nine hundred and twenty-five feet deep.
In town and country a pure water supply is of the utmost importance to
the health of the people and in many countries it can only be obtained
by deep and expensive boring. Various uses are made of water flowing
from artesian wells. In many places it is used to propel machinery. In
the desert of Sahara artesian wells have become of great value in making
the country near them habitable, as the flow is sufficient to irrigate
large areas of land. Two new villages have been built in the desert and
two hundred thousand palm trees have been planted about these wells. In
the Western part of the United States, where the rainfall is limited,
many artesian wells have been bored, the water being largely used for
irrigation. In California more than forty thousand acres are irrigated
from flowing wells. The average depth of these wells is about two
hundred and fifty feet and the average discharge eighty thousand gallons
per day.