When a party is sufficiently strong, a picket guard should be stationed during the night some two or three hundred yards in advance of the point which is most open to assault, and on low ground, so that an enemy approaching over the surrounding higher country can be seen against the sky, while the sentinel himself is screened from observation. These sentinels should not be allowed to keep fires, unless they are so placed that they can not be seen from a distance. During the day the pickets should be posted on the summits of the highest eminences in the vicinity of camp, with instructions to keep a vigilant lookout in all directions; and, if not within hailing distance, they should be instructed to give some well-understood telegraphic signals to inform those in camp when there is danger. For example, should Indians be discovered approaching at a great distance, they may raise their caps upon the muzzles of their pieces, and at the same time walk around in a circle; while, if the Indians are near and moving rapidly, the sentinel may swing his cap and run around rapidly in a circle. To indicate the direction from which the Indians are approaching, he may direct his piece toward them, and walk in the same line of direction. Should the pickets suddenly discover a party of Indians very near, and with the apparent intention of making an attack, they should fire their pieces to give the alarm to the camp. These telegraphic signals, when well understood and enforced, will tend greatly to facilitate the communication of intelligence throughout the camp, and conduce much to its security. The picket guards should receive minute and strict orders regarding their duties under all circumstances, and these orders should be distinctly understood by every one in the camp, so that no false alarms will be created. All persons, with the exception of the guards and herders, should after dark be confined to the limits of the chain of sentinels, so that, if any one is seen approaching from without these limits, it will be known that they are strangers. As there will not often be occasion for any one to pass the chain of pickets during the night, it is a good rule (especially if the party is small), when a picket sentinel discovers any one lurking about his post from without, if he has not himself been seen, to quietly withdraw and report the fact to the commander, who can wake his men and make his arrangements to repel an attack and protect his animals. If, however, the man upon the picket has been seen, he should distinctly challenge the approaching party, and if he receives no answer, fire, and retreat to camp to report the fact.