A man with a red flag indicates the position of a hostile battery, or, if the battery is concealed, a position that can be seen and is in the general direction of the battery. When the flag is waved rapidly it indicates a rafale or violent burst of fire; waved very slowly, it indicates slow fire by battery. In most exercises no flag is necessary; the instructor can give verbally the direction from which the artillery fire is coming in stating the problem; but in practicing the attack formation, under combined artillery and infantry fire, the flags should be used to practice platoon leaders in the rushes under such conditions. [Sidenote: Infantry as an artillery support] Infantry is sometimes detailed to support batteries that are somewhat separated from the rest of the troops and liable to attack by a rush of infantry or cavalry. Officers on this duty must thoroughly understand their mission. They must protect the artillery. Artillery can generally take ample care of itself if the attack comes directly from the front. The infantry commander must never mask the fire of the guns. Where he will place his men and what his general dispositions will be is a problem in tactics and the solution will vary with each case. These general propositions may be stated: his position must be such that from it he can effectively meet the attack; it should not be where he will get too much of the fire directed on the batteries; the command must be well in hand and the reconnaissance and observation groups so employed that he will have timely warning of the hostile approach and be prepared to meet it. His position will generally be to a flank and probably somewhat to the rear, never in front of the guns. An occasional exercise in this work should be carried out as a maneuver. Something should be placed to represent the guns and a battalion or company assigned as their protection while another force is given the mission to capture them. This exercise should always be carefully umpired to see that the guns get credit for what they could do if fire is not masked. A problem of this kind is a small part of the work of infantry in war and when it comes it is a tactical problem like any other attack or defense. The reason for recommending it is that it affords excellent practice in security and information service and in combat when one position must be avoided. Combat exercises should be as varied as possible, here is another variety. [Sidenote: Fire superiority] The importance of fire superiority has already been dwelt upon as well as how much the effectiveness of hostile fire falls off as the effectiveness of our own increases. Infantry alone does not gain this fire superiority but it gains it by the help of our powerful ally and sister arm, the artillery. [Sidenote: Artillery fire over infantry]