"Where did the call come from?" went on McGlory, mystified.
"It seemed to come from everywhere, and from nowhere," replied Matt. "Look into the menagerie tent, Joe."
While McGlory was lifting the canvas and taking a look through the animal show, Matt rounded the outside of the lean-to, searching every place with keen eyes.
Carl was nowhere to be found. As Matt drifted back toward the door of the calliope tent, McGlory emerged and joined him.
"He's not mixed up with the animals," reported the cowboy.
"And I can't get any trace of him out here," said Matt. "Let's walk over to the aëroplane. Carl and Ping were to watch the machine, and I'm pretty sure neither of them would leave it without orders unless something pretty serious had gone wrong."
Vaguely alarmed, the two chums pushed their way through the crowd toward the place where the Comet had been left.
[CHAPTER IX.]
BLACK MAGIC.