"A man," said the captain.
They both listened again. The mysterious whistle was suddenly repeated, and something like a report followed it, but almost inaudibly, for the storm just then broke forth with renewed violence. They could not hear themselves talk, and took their stations to leeward of the cart.
At this moment the leathern curtains were raised, and Glenarvan joined his two companions. He likewise had heard the suspicious whistle, and the report.
"From what direction?" he asked.
"Yonder," said the captain, pointing to the dark line, towards which Mulready had gone.
"How far?"
"The wind carried it," was the reply. "It must be three miles distant at least."
"Let us go!" said Glenarvan, throwing his rifle over his shoulder.
"No," interposed the major; "it is a decoy to entice us away from the cart."
"But if Mulready has fallen beneath the shots of these wretches!" continued Glenarvan, seizing MacNabb's hand.