"No ship would fire cannon here, even if wrecked.

There wouldn't be one chance in ten thousand of its being heard by another vessel." _Boom!_ "Hark! did you not hear that splashing noise that followed the explosion ?" demanded Kit.
We had all heard it; for, by this time, the sailors who were below had come on deck.

The heavy rumbling noise began afresh, and sounded louder than before.

We were completely mystified, and stood peering off from the bulwarks into the stormy obscurity of the night.
"Are there volcanoes on these straits, suppose ?" Wade asked.
No one had ever heard of any.
"There were none in my geography," said Raed.

"But there may be one _forming_." Indeed, we were so much in doubt, that even this improbable suggestion was caught at for the moment.
"But where's the fire and smoke ?" replied Kit.