“In your mind!” returned Carl.
“Watch me!” advised Jimmie.
The boys went back to the camp-fire and stood for some moments watching the changing lights on the mountain.
“I’d like to know if some one is really talking back to that fellow,” Jimmie said, turning to Mr. Havens.
“I presume some one is answering the signals,” the millionaire answered, “only we can’t see the answers given.”
“Perhaps we could learn what they’re saying if we could see the answers. They may be talking in a code we could get next to.”
“Well, you don’t see anything that looks like a return signal, do you?” asked Ben. “They’ll take good care that we don’t see both ends of the conversation.”
“Look here,” proposed Jimmie, “why don’t we send Ben up in a machine to look over the landscape. The return signals may come from some point not to be seen from this end of the valley.”
“That’s the idea!” exclaimed Carl, understanding in a minute why his chum had suggested that Ben make the midnight flight.
“Not for me!” answered Ben. “I don’t care about going up into the sky refrigerator this time of night!”