"If he sees a force advancing he must gallop back at full speed to his comrade, and light the fire. Have a gun always loaded on the keep, and have a brazier burning hard by, with an iron in it, so that the piece may be fired the instant smoke is seen. It might be two or three minutes before the beacon would give out smoke enough to be noticed, and every minute may be of the greatest importance to the vassals. As soon as you return from setting the posts see that everything is in readiness here. I myself will make sure that the drawbridge works easily and the portcullis runs freely in its groove. I have already sent off John Harpen to warn the tenants, and doubtless many of them will be in this afternoon. Send Pierre with four men, and tell them to drive up a number of the cattle from the marshes. They need not trouble to hunt them all up today. Let them bring the principal herd, the others we will fetch in to-morrow, or let them range where they are until we have further news."