Dick paused suddenly, listening keenly.

"Do you fellows hear that?" he whispered.

"I hear a rumble of wheels off in the distance," replied Greg. "The air is so wonderfully still that sound carries a long way this evening."

Dick ran into the tent, returning with an envelope and a pad of paper.

"Come along, Dave," Dick requested. "And you'd better bring Tom's flashlight. It will be dark before we get back."

The battery of the flashlight having had a good rest, now furnished an excellent light again.

As the two chums set off at a trot Greg inquired:

"Now what are that pair up to?"

"Being one of the four pin-heads belonging to this outfit," Tom made solemn reply, "I can only guess."

"Then what's your guess?" quizzed Danny Grin.