=Fix bayonets.= =Charge.= =Assemble, march.= These signals are used only when intended for the entire firing line; hence they can be authorized only by the commander of a unit (for example, a regiment or brigade) which occupies a distinct section of the battlefield. Exception: =Fix bayonet.= (See par. 355.) The following bugle signals are used in exceptional cases on the battlefield. Their principal uses are in field exercises and practice firing. =Commence firing:= Officers charged with fire direction and control open fire as soon as practicable. When given to a firing line, the signal is equivalent to =fire at will=. =Cease firing:= All parts of the line execute =cease firing= at once. These signals are not used by units smaller than a regiment, except when such unit is independent or detached from its regiment. (41) Whistle Signals =91. Attention to orders.= A =short blast= of the whistle. This signal is used on the march or in combat when necessary to fix the attention of troops, or of their commanders or leaders, preparatory to giving commands, orders, or signals. When the firing line is firing, each squad leader suspends firing and fixes his attention at a =short blast= of his platoon leader's whistle. The platoon leader's subsequent commands or signals are repeated and enforced by the squad leader. If a squad leader's attention is attracted by a whistle other than that of his platoon leader, or if there are no orders or commands to convey to his squad, he resumes firing at once. =Suspend firing.= A =long blast= of the whistle. All other whistle signals are prohibited. (42) Arm Signals =92.= The following arm signals are prescribed. In making signals either arm may be used. Officers who receive signals on the firing line "repeat back" at once to prevent misunderstanding. [Illustration] =Forward, MARCH.= Carry the hand to the shoulder; straighten and hold the arm horizontally, thrusting it in the direction of march. This signal is also used to execute quick time from double time. [Illustration] =Halt.= Carry the hand to the shoulder; thrust the hand upward and hold the arm vertically. =Double time, MARCH.= Carry the hand to the shoulder; rapidly thrust the hand upward the full extent of the arm several times. [Illustration] =Squads right, MARCH.= Raise the arm laterally until horizontal; carry it to a vertical position above the head and swing it several times between the vertical and horizontal positions. [Illustration] =Squads left, MARCH.= Raise the arm laterally until horizontal; carry it downward to the side and swing it several times between the downward and horizontal positions. [Illustration] =Squads right about, MARCH= (if in close order) or, =To the rear, MARCH= (if in skirmish line). Extend the arm vertically above the head; carry it laterally downward to the side and swing it several times between the vertical and downward positions. [Illustration]