As soon as the belated meal was over and the "camp fire" fairly in swing, Atherton called Simpson aside.
"What do you say to keeping watch all night?" he asked. "It may be a useless job, but there is something not quite right. I want to find out who the mysterious visitor to the Island is, and what he comes here for."
"I'm game," answered the Leader of the "Wolves." "We'll pick one fellow from each patrol and take two hours each; that will carry us through till sunrise, and I don't fancy any night prowler will be knocking about after that."
"Beastly rotten night to keep watch, though," commented the "Otters" Leader. "The mist is turning to rain. Tell those fellows to pile on more wood, make sure the tent pegs are firm and the guy-ropes eased off. They had better get into the tents before they get drenched."
With the rain the wind rose. At first it was content with moaning fitfully, but before nine o'clock it was literally howling, the explosive fog-signals still maintaining their accompaniment every five minutes.
"What's that noise?" asked Armstrong, in the interval between two stirring choruses.
The Scouts listened. Above the roar of the wind and the loud tattoo of the rain upon the drum-like canvas of the tents came a weird screech, like the shriek of a human being in agony.
"There it is again!" exclaimed Baker. "Perhaps some one has fallen over the cliff."
"It's too loud for a man's voice," said Simpson.
"All the same I don't like it," remarked Reggie Scott, in a subdued voice.