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.