43. 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.
_Forward, march._ Carry the hand to the shoulder; straighten and hold the arm horizontally, thrusting it in direction of march.
This signal is also used to execute quick time from double time.
_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.
_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.
_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.
_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.
_Change direction_ or _Column right (left), march._ The hand on the side toward which the change of direction is to be made is carried across the body to the opposite shoulder, forearm horizontal; then swing in a horizontal plane, arm extended, pointing in the new direction.
_As skirmishers, march._ Raise both arms laterally until horizontal.
_As skirmishers, guide center, march._ Raise both arms laterally until horizontal; swing both simultaneously upward until vertical and return to the horizontal; repeat several times.
_As skirmishers, guide right (left), march._ Raise both arms laterally until horizontal; hold the arm on the side of the guide steadily in the horizontal position; swing the other upward until vertical and return it to the horizontal; repeat several times.
_Assemble, march._ Raise the arm vertically to its full extent and describe horizontal circles.
_Range_, or _Change elevation._ To announce _range_, extend the arm toward the leaders or men for whom the signal is intended, fist closed; by keeping the fist closed battle sight is indicated; by opening and closing the fist, expose thumb and fingers to a number equal to the hundreds of yards; to add 50 yards describe a short horizontal line with forefinger. _To change elevation_, indicate the _amount of increase_ or _decrease_ by fingers as above; point upward to indicate increase and downward to indicate decrease.