unset," I exclaimed.

"And why shouldn't it appear so?" said the matter-of-fact doctor.
"Twilight is the commonest phenomenon of refraction with which we are
acquainted, and sunrise and sunset are merely a mixture of refraction
and reflection. There is nothing new about it."

"Now, Doctor, we must remain friends, but you shall not continually
tarnish my poetry with your accursed science! I thank my Creator that
He made me ignorant enough to admire the beauties of nature. You are
continually peeping behind the scenes, and pointing out the grease
paints, the lime-lights and the sham effects. Let me enjoy the beauty of
the tableau, no matter how it is produced. I would give all of your pat
knowledge for that feeling of profound awe which rises in the untutored
breast at beholding the magnificent grandeur of unfamiliar nature."

"When your ecstasy has quite passed, I shall appreciate a little cold
mutton and biscuits, and then we must pump out again," he replied.

CHAPTER XI

Telling the Time by Geography

After supper I went up into his compartment, and having arranged the
bulkhead, began the tedious operation at the pump handle. It was a
matter of pure muscular strength, as the effort had to be made to lift
the handle, which snapped back sharply when released. I was working
vigorously when I was suddenly struck dumb at seeing the handle break
off just at the point of leverage, so that it was quite impossible to
operate it. The doctor heard the handle fall, and looked around in great
vexation.

"That means asphyxiation within twenty-four hours!" he exclaimed.

"Which is plenty of time to think it over," I answered.

After all, why was this pumping necessary? If a way could be devised to
open a valve, all the air would rush out of my compartment as easily as
beer runs out of a bung-hole. In fact, it did rush out a little at a
time, which is what made the handle go down of itself. But any such new
valve would have to be automatically closed, as it would be manifestly
impossible to enter and shut it. I kept on thinking, and finally began
examining the partition between the compartments. There seemed to be
several long screws that went quite through it.

"Doctor, did you ever hear of those wise people who, after every
freshet, shipped the surplus water down the river in boats? Well, it
strikes me this air-pumping is just about as useless labour. Help me
pull in the bulkhead and I will show you something."