Merriwell saw them and shouted something to them, but they could not understand what he said.
“Turn! turn!” screamed Jack. “You must fight that man, or he will stab you in the back! He is going to strike you!”
Frank seemed to hear and comprehend, for he suddenly wheeled about and made a stand. In a moment the man with the knife had rushed upon him and struck with that gleaming blade.
A groan escaped Jack’s lips as he saw that blow, but it turned to a gasp of relief when Frank stopped it by catching the man’s wrist.
“Give it to him! Give it to him!” shrieked Diamond, dancing around in a wild frenzy of anxiety and fear.
Then the boys below witnessed a terrific struggle on the heights above them.
The man seemed mad with a desire to plunge the knife into Frank, and it was plain that Merriwell did not wish to harm the unknown, but was trying to disarm him.
“What folly! what folly!” panted Diamond. “He’ll get his hand free and stab Merry sure! Beat him down, Frank—beat him down!”
Once Frank slipped and fell to his knees. A fierce yell of triumph broke from the man, and it seemed that he would succeed in using the knife at last.
With a groan of anguish Diamond covered his eyes that he might not witness the death of the friend he loved. For Jack Diamond did love Frank Merriwell, for all that he had complained against him of late.