ome trepidation.

"Now smell it."

I did so.

"What odor do you perceive?"

"Potassium," I replied.

"Of course," he added, "you are familiar with the chief characteristic
of that substance. It ignites instantly when brought in contact with
water. Within that little globule of potassium, I have imbedded a pill
of my own composition and discovery. The moment it is liberated from the
potassium, it commences the work of decomposing the fluid on which it
floats. The potassium at once ignites the liberated oxygen, and the
conflagration of this mighty globe is begun."

"Yes," said I, "begun, if you please, but your little pill soon
evaporates or sinks, or melts in the surrounding seas, and your
conflagration ends just where it began."

"My reply to that suggestion could be made at once by simply testing
the experiment on a small scale, or a large one, either. But I prefer
at present to refute your proposition by an argument drawn from nature
herself. If you correctly remember, the first time I had the pleasure
of seeing you was on the island of Galveston, many years ago. Do you
remember relating to me at that time an incident concerning the effects
of a prairie on fire, that you had yourself witnessed but a few days
previously, near the town of Matagorde? If I recollect correctly, you
stated that on your return journey from that place, you passed on the
way the charred remains of two wagon-loads of cotton, and three human
beings, that the night before had perished in the flames; that three
slaves, the property of a Mr. Horton, had started a few days before to
carry to market a shipment of cotton; that a norther overtook them on
a treeless prairie, and a few minutes afterward they were surprised by
beholding a line of rushing fire, surging, roaring and advancing like
the resistless billows of an ocean swept by a gale; that there was no
time for escape, and they perished terribly in fighting the devouring
element?"

"Yes; I recollect the event."

"Now, then, I wish a reply to the simple question: Did the single spark,
that kindled the conflagration, consume the negroes and their charge?
No? But what did? You reply, of course, that the spark set the entire
prairie on fire; that each spear of grass added fuel to the flame, and
kindled by degrees a conflagration that continued to burn so long as
it could feed on fresh material. The pilule in that vial is the little
spark, the oceans are the prairies, and the oxygen the