e carriage, I will listen."

"Because of my friendship for you, I will make it as brief as
possible. In the first place, you must know that before oil is struck,
the operator finds either a rock formed of sand or of gravel. This is
the strata just above the deposit of petroleum.

"Of course this must be bored through, if possible, and in the pebbly
rock there is no trouble about it. The drills will go through, and the
gravel will be forced to the surface without much difficulty. But when
the sand-rock is met, it clogs the drills, making it almost impossible
to bore through. A heavy charge of nitro-glycerine makes short work of
this rock, and out comes the oil.

"Now, this method of blasting in oil wells has been patented, or, at
least, the cases for the glycerine and the manner of exploding it has,
and the company, which has its office in Bradford, use every effort to
discover infringements of their patent. Like all owners of patent
rights, they charge an extra price for their wares, and the result is
that there are parties who will, for a much smaller amount of money,
shoot a well and infringe the patent at the same time. These people are
called moonlighters, and the risk they run of losing their lives or
their liberty is, to say the least, very great. The lecture-hour has now
been fully, and I hope I may say profitably, employed."

"If it profits one to learn of your friends, the moonlighters, then your
lecture has been a success. But how do you find excitement in anything
they do? Surely they do not make public their unlawful doings."

"Oh, everything save the shooting of the well is done legally, and with
many even that is questionable! The cases are to be tried, and many
believe that the owners of the patent have really no rights in the
premises. The owners or prospective owners of the land whereon the wells
are to be sunk, employ me to survey their tracts, and by that means I
frequently make the acquaintance of those people who, for the almighty
dollar, will peril their lives driving around the country with
nitro-glycerine enough to blow an entire town up."

"Let me trespass once more on you for dry detail, and then I will learn
anything else I may want to know from observation. What is
nitro-glycerine?"

"I will answer your question by quoting as nearly as I can from what I
read the other day. It is composed of:

Aqueous vapor 20 parts.
Carbonic acid 58 "
Oxygen 3.5