He would have brought the lantern with him when he first came, but they had no oil except what it contained, and this they had husbanded for emergencies.

But now the captain wanted light--he cared not what might happen afterwards.

In a very short time, with the lantern in his hand, which lighted up the cave for a considerable distance about him, the captain again stood at the foot of the subterranean dome.
He walked around it.

He raised and lowered his lantern, and examined it from top to bottom.

It was one half a sphere of masonry, built in a most careful manner, and, to all appearances, as solid as a great stone ball, half sunken in the ground.