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.