“No,” he decided, “I will see that he is cooked in advance.”

He went into town, and was seen talking with some lads who seemed rather disreputable in appearance.

Friday came. Among the first to reach the park for practice was Merriwell and Hodge. Frank was going to pitch to Bart a while before all the team assembled on the field.

It happened that Bart and Costigan were the first to get out of the dressing room, and Frank was left putting on his shoes. He finished his task, and rose to his feet. As he did so, the door opened and a rough-looking chap dodged in.

“Hello!” exclaimed Frank, in surprise. “Who are you, and what are you doing here?”

The fellow caught up a bat and swung it aloft.

“Shut up!” he hissed. “If you holler, I’ll split your head open!”

Then he gave a sharp whistle.

Frank knew that whistle was a signal, and he instantly realized crooked work was a-foot. With his eyes he measured the distance to the intruder. An instant later, he made a catlike spring, caught hold of the bat, twisted it from the fellow’s hand, and had him by the collar.

“You infernal sneak!” he cried. “What is your game? I am onto you!”