“They will be informed as to the points to which the roads and trails lead, and, if practicable, the names of important topographical points in sight. “They will be given the countersign, if one is used. The method of challenge and identification of persons approaching the outpost sentinels at night should be changed from time to time so that there will be less chance for the enemy to know just what system is being used on a particular night. On one occasion a countersign using the name of a battle or general may be used; on another night the system of tapping the knuckles on the rifle stock may be employed. “The mistake of giving sentinels too many orders and instructions should be carefully avoided. If their minds are burdened with too many details, they are likely to become hesitating, timid and confused. The controlling idea is that they should know where to look for the enemy and what to do if they see him.” Solution _The Director_: “Captain Hall, having in mind what I have just said, what orders would you give your sentinels?” _Captain Hall_: “I would give them the following orders: “‘You have all the information of the enemy and our own troops. “‘You are double sentinel post No. 1 of outguard No. 2 of support No. 1. Outguard No. 1 is —— (point out location). Outguard No. 3 is —— (point out location). Information of the exact location of the sentinel posts will be given to you later. “‘This road leads to ——. That trail leads in the direction of ——. That —— is known as the ——. (Note—Locate and name other important topographical features in view.) “‘If you see the enemy, signal to me at the outguard. “‘The countersign will be given to you later.’” _The Director_: “I think that covers the orders for your sentinel very well. The big idea is that we should not burden them with too many things to think about. We will omit the written solution of this part of the problem.” Explanation _The Director_: “There are certain rules for the guidance of a sentinel on post with which all officers and soldiers should be familiar. They must be scrupulously observed under all circumstances. They are: “1. He must watch and listen without betraying his presence. Observation is the first consideration and concealment of secondary importance. “2. He must not smoke, and matches must not be lighted at night. “3. Such conversation as is absolutely necessary must be conducted in subdued tones. “4. He must not have any arms or accoutrements that will glitter in the sunlight. “5. Except at night and in foggy weather, the bayonet must be kept in the scabbard. “6. Persons arrested are ordinarily held at the post until a patrol comes out to take charge of them. “7. He will not allow his vigilance to be disturbed by the requirements of military etiquette. He pays no compliments and does not salute officers unless addressed by them.