Fundamental to any movement is turning the soldiers within their files and ranks, and by turning they orient themselves to specified directions in relation to their original direction. For turning, Colonel Barriffe details: "...every man is to turn upon the ball or center of the left foot, & move from the ground onely with the right: The left foot being the keeper of rank...."* Sergeant Subtlelus says: Direction provided in any command is by the unit's orientation.  In particular, "By the left hand" and "By the right hand" refer to the left and right sides of the unit.  For an officer or sergeant facing the unit, "Face to the left" is to his right and "Face to the right" is to his left.  Even in the heat of engagement, the officer must always keep in mind his reference point to his unit.  That these persons do not become confused and disoriented by such seeming contradictions is why they are officers and sergeants.   *Chapt 9, The Young Artilleryman...