605. A patrol is a detachment sent out from a command to gain information of the country or of the enemy, or to prevent the enemy from gaining information. In special cases patrols may be given missions other than these. 606. The commander must have clearly in mind the purpose for which the patrol is to be used in order that he may determine its proper strength, select its leader, and give the latter proper instructions. In general, a patrol should be sent out for one definite purpose only. 607. The strength of a patrol varies from two or three men to a company. It should be strong enough to accomplish its purpose, and no stronger. If the purpose is to gain information only, a small patrol is better than a large one. The former conceals itself more readily and moves less conspicuously. For observing from some point in plain view of the command or for visiting or reconnoitering between outguards two men are sufficient. If messages are to be sent back, the patrol must be strong enough to furnish the probable number of messengers without reducing the patrol to less than two men. If hostile patrols are likely to be met and must be driven off, the patrol must be strong. In friendly territory, a weaker patrol may be used than would be used for the corresponding purpose in hostile territory. 608. The character of the leader selected for the patrol depends upon the importance of the work in hand. For patrolling between the groups or along the lines of an outpost, or for the simpler patrols sent out from a covering detachment, the average soldier will be a competent leader. 609. For a patrol sent out to gain information, or for a distant patrol sent out from a covering detachment, the leader must be specially selected. He must be able to cover large areas with few men; he must be able to estimate the strength of hostile forces, to report intelligently as to their dispositions, to read indications, and to judge as to the importance of the information gained. He must possess endurance, courage, and good judgment. His instructions should be full and clear. He must be made to understand exactly what is required of him, where to go and when to return. He should be given such information of the enemy and country as may be of value to him. He should be informed as to the general location of his own forces, particularly of those with whom he may come in contact. If possible, he should be given a map of the country he is to traverse, and in many cases his route may be specified. Besides his arms and ammunition, the patrol leader should have a compass, a watch, a pencil, a note book, and, when practicable, field message blanks and a map of the country.