He held up his left hand to glance at his wrist watch.

Just as he turned the hand, to let it fall at his side, something dropped out of the air, falling squarely in his hand.

Instinctively Prescott's fingers closed over the missile.

He glanced, quickly, at the enclosure, but not one of the men on the other side of the wire was looking his way.
Then the young captain, keeping briskly on his way, opened his hand to glance down at his unexpected catch.

It was a piece of manila paper, wrapped around a stone.
Waiting only until he was some distance from the bull-pen, Dick unwrapped the paper.
In printed characters, used undoubtedly to disguise handwriting, was this message: "Watch for all you're worth the carpenter who talks with Mock!" "Now, why on earth should I interest myself in the affairs of Greg's busted sergeant ?" Dick wondered.