"There's only one thing I don't understand," said the superintendent, when Allan had finished, turning back to Jim, "and that is how you came to have that fusee." Jim reddened. "I found it, sir," he explained. "You remember when the caboose of Number Ninety-seven was derailed about a month ago, near the bridges, and rolled down the bank and was smashed to pieces?" "Perfectly," answered the superintendent, dryly. "Well," Jim continued, "I suppose the box of fusees in the caboose must have been broken open and scattered about. Anyway, I found this one the next day in some bushes at the foot of the embankment. I suppose I should have returned it to the company--but--well--I thought I'd keep it for the Fourth of July." His voice trembled and stopped, and he stood with hanging head, like a criminal waiting his sentence. Let it be explained here that a fusee is a paste-board tube filled with powder--the same sort of powder which produces the red fire which forms a part of every exhibition of fire-works. At one end of this tube is a spike which can be thrust into the ground. The other end of the tube is closed by a cap containing a piece of emery-paper. To light the powder it is only necessary to remove the cap and scrape it on the end of the tube till a spark falls into it. A fusee burns with a bright red light for exactly ten minutes, and no train may run past one which is burning. Its uses are manifold. It makes a brilliant danger signal, and one which no engineer can fail to see, which no mist nor snow can obscure, and which no wind can extinguish. But it is usually used by night--as torpedoes are by day--to protect the rear of a train which has been temporarily disabled and delayed between stations. If a train is stopped by a hot-box, for instance, a brakeman is at once sent out to protect the rear. He walks to a distance of two or three hundred yards, carrying a flag in the daytime or a lantern by night, with which to stop any train which may happen to come along before his train is ready to proceed. Ordinarily, there is no danger to be apprehended from in front, because the dispatcher will permit no train coming toward them to pass the next station until the train which is in trouble arrives there.