es to haul the cars.

I noted also that most of the buildings are built against a hillside or
surrounded by heavy mounds of earth, so that if one of them blows up,
the others may be protected against the flight of debris. Without such
barricade the shattered walls and rocks would be hurled in all
directions with the energy of cannonballs, and a single explosion would
probably mean the destruction of the entire works.

At one place I saw a triangular frame of timbers and iron supporting a
five-hundred-pound swinging mortar, that hung down like a great gipsy
kettle under its tripod. In front of this mortar was a sand-heap, and
here, I learned, were made the tests of dynamite, a certain quantity of
this lot or that being exploded against the sand-heap, and the mortar's
swing back from the recoil giving a measure of its force. The more
nitroglycerin there is in a given lot of dynamite, the farther back the
mortar will swing. It should be understood that there are many different
grades of dynamite, the strength of these depending upon how much
nitroglycerin has been absorbed by a certain kind of porous earth.

In a little white house beyond the laboratory I found the superintendent
of the works, a man of few words, accustomed to give brief orders and
have them obeyed. He did not care to talk about dynamite--they never do.
He did not think there was much to say, anyhow, except that people have
silly notions about the danger. He had been working with dynamite now
for twenty-five years, and never had an accident--that is, himself. Oh,
yes; some men had been killed in his time, but not so many as in other
occupations--not nearly so many as in railroading. Of course there was
danger in dealing with any great force; the thing would run away with
you now and then; but on the whole he regarded dynamite as a very well
behaved commodity, and much slandered.

"Then you think dynamite-workers have no great need of courage?" I
suggested.

"No more than others. Why should they? They work along for years, and
nothing happens. They might as well be shoveling coal. And if anything
does happen, it's over so quick that courage isn't much use."

Having said this, he hesitated a moment, and then, as if in a spirit of
fairness, told of a certain man at the head of a nitroglycerin-mill who
on one occasion _did_ do a little thing that some people called brave.
He wouldn't give the name of this "certain man," but I fancied I could
guess it.