The pursuer carried in his hand a canvas bag filled with sand.

This, though Joe did not know it, was a dangerous weapon in the hands of a lawless human.

Brought down heavily upon the head of an unlucky traveler, it often produced instant death, without leaving any outward marks that would indicate death from violence.
Though Joe didn't comprehend the use of the sand-bag, his own recent experience and the stealthy movement of the man behind convinced him that mischief was intended.

He would have been excusable if, being but a boy and no match for an able-bodied ruffian, he had got out of the way.

But Joe had more courage than falls to the share of most boys of sixteen.