"Most ghosts, I'm told," chuckled Joe, "prefer to walk when there's someone about, for what's the good of a ghost-walk when there's no one to see. So our radio ghost may show up after all."

Curlie lapsed into silence. He was reviewing the events which led up to this thrilling moment. When the message on 600 came banging to his ears with great power on that first night, he had carefully platted the various locations of the person who had sent the messages. There had been some criss-crosses shown but, in the main, a line drawn through these points had formed an oblong which on the actual surface of the ground must have been some ten miles in length by six in width. One interesting point was that the first and last messages of that night had been sent at points not a quarter of a mile apart.

"Which goes to show," he reasoned, "that this fellow started from a certain point and made his way back to that point, just as a rabbit will do when chased by a hound. And those two points, the start and the finish, are close to the driveway into the million dollar estate. But of course that doesn't prove that the car came from there. Any person could drive to that point, begin operations, race over the square and return to the point."

Coles Masters had platted the points for the second night. A line drawn through these points made a figure quite irregular in form, which was, however, composed of rectangles.

"Which proves," he told himself, "that our friend, the lawless radio fan, drives an auto and not an airplane. An auto follows roads, which for the most part in this section form squares. He passed along two or three sides of these squares and this makes up the figure.

"There's only one thing in common in the two night journeys," he continued. "The start and finish are at almost exactly the same spot, near the entrance of that great estate."

He tried not to allow these facts to cause him to hold undue suspicion against the inhabitants of that mansion, but in this he experienced some difficulty.

"The thing for us to do," he had said to Joe, "is to run out there and back our car into an unfrequented, wooded road running into the forest preserve. We don't dare go too near the original starting place. If we're seen with this load of junk it will give us dead away. Thing is to be ready to move quickly when he lets loose with his message. Ought not to be more than a mile away, I'd say. He's got a powerful car. You can tell that by the fact that he sent a message at this corner, then raced over here, four miles distant, and got another message off in eleven minutes, which is quick action."

They backed into the grass-grown road of the Forest Preserve, then settled down in their places to wait.

The night was dark. There was no moon. Clouds were scurrying overhead. Only the rustle of leaves and the startled tweet-tweet of some bird surprised in his sleep disturbed the utter silence of the woods.