He knew that Trot was right, though.

To remain in the cavern, where they now were, could only result in slow but sure death.
It was nighttime up on the earth's surface, so the little girl became drowsy and soon fell asleep.

After a time the old sailor slumbered on the sands beside her.

It was very still and nothing disturbed them for hours.

When at last they awoke the cavern was light again.
They had divided one of the biscuits and were munching it for breakfast when they were startled by a sudden splash in the pool.