She vibrated from one end to the other, and stopped for a moment in her course.

Felix sprang up alarmed.

At the same instant a bellowing noise reached him, succeeded by a frightful belching and roaring, as if a volcano had burst forth under the surface of the water; he looked back but could see nothing.

The canoe had not touched ground; she sailed as rapidly as before.
Again the shock, and again the hideous roaring, as if some force beneath the water were forcing itself up, vast bubbles rising and turning.
Fortunately it was at a great distance.

Hardly was it silent before it was reiterated for the third time.