Fox fire

"There is still another method of night hunting by the salt lick. [...] When night approaches, the hunter finds a piece of phosphorescent wood or "fox fire," and places it on the ground, at a point which he has previously determined to be on a direct line of the aim of his gun. The "fox fire" is plainly seen from the tree, and as soon as it is darkened he knows that it is obscured by the deer, and he pulls the trigger and kills his game."