"Night time is the best and offers the only slender chance we have, for then men sleep, and only a dozing watch nods in the tops of the battleships. No watch is kept upon the cruisers and smaller craft. The watchers upon the larger vessels see to all about them. It is night now."

"But," I exclaimed, "it is not dark! How can it be night, then?"

He smiled.

"You forget," he said, "that we are far below ground.

The light of the sun never penetrates here. There are no moons and no stars reflected in the bosom of Omean.

The phosphorescent light you now see pervading this great subterranean vault emanates from the rocks that form its dome; it is always thus upon Omean, just as the billows are always as you see them--rolling, ever rolling over a windless sea.

"At the appointed hour of night upon the world above, the men whose duties hold them here sleep, but the light is ever the same."

"It will make escape more difficult," I said, and then I shrugged my shoulders; for what, pray, is the pleasure of doing an easy thing?

"Let us sleep on it to-night," said Xodar. "A plan may come with our awakening."

So we threw ourselves upon the hard stone floor of our prison and slept the sleep of tired men.