Among the Forces | Page 9

York.
How can man combat part of the continent on the move, driven by the
ceaseless powers of the air? By a humble plant or two. The movement
of the sand hills that threaten to destroy the marvelous beauty of the
grounds of the Hotel del Monte at Monterey is stopped by planting
dwarf pines. The sand dunes that prevent much of Holland from being
reconquered by the sea are protected with great care by willows, etc.,
and the coast sands of parts of eastern France have been sown with sea
pine and broom.
The tract of a thousand acres on Cape Cod had been protected by
humble beach grass. Some careless herder let the cows eat it in places,
and away went part of a township. It is now a punishable crime on
Cape Cod to destroy beach grass.

GAS HELP
This refers to more than stump speech-making. The old Romans drove
through solid rock numerous tunnels similar to the one for draining
Lago de Celano, fifty miles east of Rome. This one was three and a half
miles long, through solid rock, and every chip cost a blow of a human
arm to dislodge it. Of course the process was very slow.
We do works vastly greater. We drive tunnels three times as long for
double-track railways through rock that is held down by an Alp. We
use common air to drill the holes and a thin gas to break the rock. The
Mont Cenis tunnel required the removal of 900,000 cubic yards of rock.
Near Dover, England, 1,000,000,000 tons of cliff were torn down and
scattered over fifteen acres in an instant. How was it done? By gas.

There are a dozen kinds of solids which can be handled--some of them
frozen, thawed, soaked in water, with impunity--but let a spark of fire
touch them and they break into vast volumes of uncontrollable gas that
will rend the heart out of a mountain in order to expand.
Gunpowder was first used in 1350; so the old Romans knew nothing of
its power. They flung javelins a few rods by the strength of the arm; we
throw great iron shells, starting with an initial velocity of fifteen
hundred feet a second and going ten miles. The air pressure against the
front of a fifteen-inch shell going at that speed is 2,865 pounds. That
ton and a half of resistance of gas in front must be much more than
overcome by gas behind.
But the least use of explosives is in war; not over ten per cent is so used.
The Mont Cenis tunnel took enough for 200,000,000 musket cartridges.
As much as 2,000 kegs have been fired at once in California to loosen
up gravel for mining, and 23 tons were exploded at once under Hell
Gate, at New York.
How strong is this gas? As strong as you please. Steam is sometimes
worked at a pressure of 400 pounds to the inch, but not usually over
100 pounds. It would be no use to turn steam into a hole drilled in rock.
The ordinary pressure of exploded gas is 80,000 pounds to the square
inch. It can be made many times more forceful. It works as well in
water, under the sea, or makes earthquakes in oil wells 2,000 feet deep,
as under mountains.
The wildest imagination of Scheherezade never dreamed in Arabian
Nights of genii that had a tithe of the power of these real forces. Her
genii shut up in bottles had to wait centuries for some fisherman to let
them out.

NATURAL AFFECTION OF METALS
"Sacra fames auri." The hunger for gold, which in men is called
accursed, in metals is justly called sacred.

In all the water of the sea there is gold--about 400 tons in a cubic
mile--in very much of the soil, some in all Philadelphia clay, in the
Pactolian sands of every river where Midas has bathed, and in many
rocks of the earth. But it is so fine and so mixed with other substances
that in many cases it cannot be seen. Look at the ore from a mine that is
giving its owners millions of dollars. Not a speck of gold can be seen.
How can it be secured? Set a trap for it. Put down something that has
an affinity--voracious appetite, unslakable thirst, metallic affection--for
gold, and they will come together.
We have heard of potable gold--"potabile aurum." There are metals to
which all gold is drinkable. Mercury is one of them. Cut transverse
channels, or nail little cleats across a wooden chute for carrying water.
Put mercury in the grooves or before the cleats, and shovel auriferous
gravel and sand into the rushing water. The mercury will bibulously
drink into itself all the fine invisible gold,