During the 15th, 16th, 17th and 18th of July, in the midst of a more fertile country, the boat drifted on the silvery waters of the river. They still took the same precautions, and it was always a mass of herbs that the current seemed to carry on its surface.
A few days more, and no doubt the survivors of the "Pilgrim" would see the termination of their miseries. Self-sacrifice had been shared in by all, and if the young novice would not claim the greater part of it, Mrs. Weldon would demand its recognition for him.
But on the 18th of July, during the night, an incident took place which compromised the safety of the party. Toward three o'clock in the morning a distant noise, still very low, was heard in the west. Dick Sand, very anxious, wished to know what caused it. While Mrs. Weldon, Jack, and Cousin Benedict slept in the bottom of the boat, he called Hercules to the front, and told him to listen with the greatest attention. The night was calm. Not a breeze stirred the atmosphere.
"It is the noise of the sea," said Hercules, whose eyes shone with joy.
"No," replied Dick Sand, holding down his head.
"What is it then?" asked Hercules.
"Wait until day; but we must watch with the greatest care."
At this answer, Hercules returned to his post.
Dick Sand stood in front, listening all the time. The noise increased.
It was soon like distant roaring.
Day broke almost without dawn. About half a mile down the river, just above the water, a sort of cloud floated in the atmosphere. But it was not a mass of vapor, and this became only too evident, when, under the first solar rays, which broke in piercing it, a beautiful rainbow spread from one bank to the other.