The bugler with the captain assists by observing the enemy, the target, and the fire effect, and by watching for and transmitting commands. The effect of fire and the influence of the ground in relation thereto, and the individual and collective instruction in marksmanship are treated in the =Small-Arms Firing Manual=. =659.= =Volley fire= has limited application. It has a moral effect both on the troops employing it and on those subjected to it. It may be employed to restore control. In defense it may be used in the early stages of the action if the enemy presents a large compact target. It may be used by troops especially posted on the flank or in a dominant position in rear of an attacking force for the purpose of aiding the advance by so-called _fire of position_. When the ground near the target is such that the strike of bullets can be seen from the firing line, ranging volleys may be used to correct the sight setting. In combat, volley firing, if used, is executed habitually by platoon. =660.= =Fire at will= is the class of fire normally employed in attack or defense. =661.= =Clip fire= has limited application. It is principally used (_a_) in the early stages of combat to steady the men by habituating them to brief pauses in firing; (_b_) to produce a short burst of fire. FIRE DIRECTION. =662.= When the troop is large enough to be divided into platoons, it is impracticable for the captain to command it in combat. His efficiency in managing the firing line is measured by his ability to enforce his will through the platoon leaders. Having indicated clearly what he desires them to do, he avoids interfering except to correct serious errors or omissions. The captain directs the fire of his troop or of designated platoons. He designates the target and, when practicable, allots a part of the target to each platoon. Before beginning the fire action he determines the range, announces the sight setting, and indicates the class of fire to be employed and the time to open fire. Thereafter he observes the fire effect, corrects material errors in sight setting, prevents exhaustion of the ammunition supply, and causes the distribution of such extra ammunition as may be received. FIRE CONTROL. =663.= In combat the platoon is the _fire unit_. From 20 to 35 rifles are as many as one leader can control effectively.