All at once Glen saw another light, apparently on the edge of the opposite bluffs. It showed yellow and steady for a second, and then disappeared. Was it an Indian signal, or a newly risen star suddenly obscured by clouds? This was a question calculated to keep even a sleepy boy wide awake. Perhaps if he watched closely he would see it again. He had heard a great deal about Indian signals lately, and knew that, by flashes of fire at night, smokes, waving blankets, and mirror flashes by day, they could transmit intelligence across the plains almost as readily as white men could do the same thing by telegraph. How he wished he understood their signals, and how he would like to see them using them.