But the examination ended only in discouragement. Smooth almost as glass the walls were, and the floor as well, perhaps worn down by countless prisoners.
The iron door, cleverly let into the wall, lay flush with it, and offered not the slightest irregularity to the touch. So nicely was it fitted that not even Stern's finger-nail could penetrate the joint.
"Nothing doing in the escape line," he passed judgment unwillingly. "Barbarians these people certainly are, in some ways, but they've got the arts of stone and iron working down fine. I, as an engineer, have to appreciate that, and give the remote descendants of our race credit for it, even if it works our ruin. Gad, but they're clever, though!"
Discouraged, in spite of all his attempted optimism, he sought the girl again, there in the deep and velvet dark. To himself he drew her; and, his arm about her sinuous, supple body, tried to comfort her with cheering speech.
"Well, Beatrice, they haven't got us yet! We're better off, on the whole, than we had any right to hope for, after having fallen one or two hundred miles--maybe five hundred, who knows? If I can manage to get a word or two with these confounded barbarians, I'll maybe save our bacon yet! And, at worst--well, we're in a mighty good little fort here. I pity anybody that tries to come in that door and get us."
"Oh, Allan--those skeletons, those headless skeletons!" she whispered; and in his arms he felt her shudder with unconquerable fear.
"I know; but they aren't going to add us to their little collection, you mark my words! These men are white; they're our own kind, even though they have slid back into barbarism. They'll listen to reason, once I get a chance at them."
Thus, talking of the abyss and of their fall--now of one phase, now another, of their frightful position--they passed an hour in the stifling dark.
And, joining their observations and ideas, they were able to get some general idea of the conditions under which these incredible folk were dwelling.
From the warmth of the sea and the immense quantities of vapor that filled the abyss, they concluded that it must be at a tremendous depth in the earth--perhaps as far down as Stern's extreme guess of five hundred miles--and also that it must be of very large extent.
Beatrice had noted also that the water was salt. This led them to the conclusion that in some way or other, perhaps intermittently, the oceans on the surface were supplying the subterranean sea.
"If I'm not much mistaken," judged the engineer, "that tremendous maelstrom near the site of New Haven--the cataract that almost got us, just after we started out--has something very vital to do with this situation.