For some time, now, the boys had been dully conscious of a peculiar
sound in the distance, just as one sometimes is of the ticking of a
clock which he takes no distinct note of. But now this mysterious sound
became more pronounced, and forced a recognition. The boys started,
glanced at each other, and then each assumed a listening attitude. There
was a long silence, profound and unbroken; then a deep, sullen boom came
floating down out of the distance.
"What is it!" exclaimed Joe, under his breath.
"I wonder," said Tom in a whisper.
"'Tain't thunder," said Huckleberry, in an awed tone, "becuz thunder--"
"Hark!" said Tom. "Listen--don't talk."
They waited a time that seemed an age, and then the same muffled boom
troubled the solemn hush.
"Let's go and see."