"
Nitrogen 18.5 "

"Until 1864 it found no practical application, except as a homeopathic
remedy for headache, similar to those which it causes. In that year,
Alfred Nobel, a Swede, of Hamburg, began its manufacture on a large
scale, and, though he sacrificed a brother to the terrible agent he
had created, he persevered until in its later and safer forms
nitro-glycerine has come into wide use and popularity. It is a clear,
oily, colorless, odorless, and slightly sweet liquid, and can, with
safety, only be poured into some running stream if one wishes to be rid
of it. Through the pores of the skin, or in the stomach, even in small
quantities, this oil causes a terrible headache and colic, while
headaches also result from inhaling the gases of its combustion. It has
thirteen times the force of gunpowder, exploding so much more suddenly
than that agent does, that in reality it is much more powerful, and it
is this same rapid explosive power that prevents it from being used in
fire-arms."

"You would make a first-rate professor, George," said Ralph, laughing,
"and you may refer to me in case you should desire to procure such a
position. Now I think I am armed with sufficient knowledge to be able to
meet your oily friends, the moonlighters, and have some idea of what
they mean when they speak."

"If I am not mistaken we shall meet some of them very soon, without
trying hard; but if we do not, I will take you to one of their cabins as
soon as we may both feel inclined to go."

"Don't think that I have come here to spend my vacation simply with the
idea that I am at liberty to make drafts at sight on your time," replied
Ralph, as an unusually rough portion of the road necessitated his
exerting all his strength to prevent being thrown out of the wagon. "I
intend to be of every possible assistance to you, and when I cannot do
that, if you are still obliged to labor, I will extract no small amount
of enjoyment out of your farm-house and its surroundings. But at any
time that you have a few hours to spare, I will be only too well pleased
to meet with any adventure, from nitro-glycerine blasts to the perils of
trout-fishing."

By this time the conversation ceased, owing to Ralph's interest in the
scenery around him, and the curious combination of oil-tanks and
derricks with which the landscape was profusely dotted. From Bradford to
Sawyer the road winds along at the base of the hills through a lovely
valley, th