He halted to study the manifestation, for to say the least it was out of the usual order of things. All lights at that time of night ought to be stationary. If it came from an emigrant camp or the window of a cabin, it would glow steadily, but a glance showed that it was moving. It had a rhythmic rise and fall, slight of itself, but distinct, such as is made by a person carrying a lighted lantern as he walks, or possibly by a horseman whose animal is on the same stride.