“Northern lights,” was his exclamation; and then, as he stood and watched the mysterious beams, he realized that his first impression was wrong. For the lights seemed to reach from the earth to the sky, and did not emanate from the heavens. Nor did they have the usual characteristics of Northern lights. They were more like the beams from some searchlight. They were six in number, and seemed to wave to and fro.
“That’s odd,” remarked the lad. “Guess I’ll call Bob and Ned, and see what they think of ’em.”
He awoke his chums, and the three gazed at the flickering lights.
“Electricity, I guess,” remarked Ned.
“That’s it,” agreed Bob. “Probably there’s a storm somewhere in the mountains.”
“Those lights are not from electricity, nor are they the reflection of some storm,” spoke a voice at the side of the boys, and they turned to see Professor Snodgrass standing beside them. “See how the lights wave to and fro regularly,” he added. “The color, too, is not natural. It is like the reflection from some fire, in which smoke is mingled.”
“What do you suppose causes them?” inquired Jerry.
“Human beings,” was the quick answer. “I think those are signal lights.”
“You’re right,” came another voice, and Mr. Bell, who, like the professor, had been awakened by the boys, came to the window. “Those are signal lights,” went on the aged man.
“Where from?” asked Jerry.