-like spectacle lasted for a short time only,
however; the golden flashes vanished one by one; the yellow became
orange, the orange deepened into crimson, and the crimson in its turn
slowly merged into a cold cobalt blue as the light died out of the
western sky; and finally the stars came out one by one until the entire
firmament was thickly studded with them. It was "nightfall on the sea."

Enthralled by the surpassing witchery of the scene, some time elapsed
before either of the travellers cared to break the silence. At length,
however, the baronet turned to the professor and said:

"I owe you a debt of never-dying gratitude, professor, for having been
the means of introducing me to a scene of such indescribable beauty as
that which we have just witnessed; I have looked upon many a fair scene
during the course of my wanderings, but never upon anything to equal
this. We must have been exceptionally fortunate to-night, have we not?
for surely the Polar world can have no spectacle more enchanting than
the one which we have just witnessed?"

"We _have_ been fortunate; there is no doubt about that," was the reply.
"But you have not yet seen the midnight sun nor the aurora borealis,
both of which sights far exceed in beauty what we have looked upon to-
night. But it grows chilly and an insidious fog is gathering round us;
we must take measures for passing the night in safety, for, were we by
chance to be caught between two icebergs of even ordinary size, not even
the enormous strength of the _Flying Fish_ would save her from
destruction."

"And what do you propose to do, then, professor, in order to ensure our
safety?"

"There are two courses open to us. One is to sink to the bottom of the
sea, which is here deep enough to secure us from all danger of being
struck by floating bergs. And the other is to ascend into the calm
belt, where the night can be passed in a state of absolute safety."

"Very well, then; let us ascend into the `calm belt,' by all means,"
said the baronet. "And, by the way, I should feel extremely obliged if
you would kindly explain to us what the `calm belt' is; I for one never
heard of it before."

"I will do so with pleasure," replied the professor. "You must know,
then, in the first place, that there are certain atmospheric currents as
regular and precise in their action as those of the ocean, both being
created by the same cause--namely, the tendency of a warm fluid to rise
and of a