Frank shuddered slightly.

“I heard it,” he said, “and I would have thought it supernatural, so like my uncle’s voice it was, had it been possible for a spirit to knock me down and bind me.”

“Strange,” she murmured. “I also thought it was your uncle calling, though I had never seen or heard him.”

“It struck me to the marrow,” said Webster, “and I fired at the sound out of sheer terror.”

They all sat silent for some time pondering over the mystery.

“It is beyond me,” said Hume wearily. “When I left you last night I expected to find some black, perhaps a woman, from the terror in the sound of her cry, fallen into the river, or caught by a crocodile, and I ran down to the bank, making noise enough to inform anyone of my whereabouts. On reaching the river I stood still, and without the slightest warning was felled to the ground. On recovering consciousness I found myself bound to a tree and gagged. It all happened within the space of ten minutes after leaving the waggon.”

“The cry was a decoy, then?”

“It must have been.”

“You saw no one?”

“No, nor heard the step of my assailant, though at the time I was listening intently.”