Once more their voices rose in such stentorian chorus that it left them breathless and Connie’s head was throbbing as from a blow.
“Hark!” said Doc. “Shhh.”
From somewhere far off came a sound, thin and spent with the distance, which died away and seemed to mingle with the voice of the breeze; then absolute silence.
“Did you hear that?”
“Nothing but a tree-toad,” said Garry.
They waited a minute to give the answering call a rest, if indeed it came from human lips, then raised their voices once again in a long Helloo.
“Hear it?” whispered Connie. “It’s over there to the east. That’s no tree-toad.”
Whatever the sound was, the distance was far too great for the sense of any call to be understood. The voice was impersonal, vague, having scarce more substance than a dream, but it thrilled the four boys and made them feel as if the living spirit of that footprint at their feet was calling to them out of the darkness.
“Even still I think it must be near the stream though it sounds way off there,” Tom pointed; “we might head straight for the sound or we might follow the stream up. It may go in that direction up a ways.”
They decided to trust to the brook’s guidance and to the probability of its verging in the direction of the sound. It wound its way through intertwined and over-arching thickets where they were forced to use their belt-axes to chop their way through. Now and again they called as they made their difficult way, challenged almost at every step by obstructions. But they heard no answering voice.