"It is the man in black!"
At the same moment, the unknown sprang forward and clutched the lad, snarling:
"Give me that ring! I will have it! Give it up peaceably, or I will choke the breath out of your body! Don't shout! It will be the worse for you if you do!"
Right there and then the man in black met with a great surprise.
Frank grappled with the stranger, and, for some moments, they engaged in a fierce struggle. At length the boy got the best of it, and, as he threw the man, he gave his assailant a terrible upper-cut blow.
Having freed himself Frank took to his heels and ran down the road toward the academy.
CHAPTER XXVIII.
THE MARKS ON THE BLACK STONE.
Frank fancied he heard pursuing footsteps behind him, but the mysterious man might have spared himself the effort if he tried to overtake the lad, for Merriwell almost flew over the ground.