"By use of an instrument called a map measurer, set the hand on the face to read zero, roll the small wheel over the distance; now roll the wheel in an opposite direction along the graphical scale, noting the number of yards passed over. A map measurer is valuable for use in solving map problems in patrolling, advance guard, outpost, etc." — Moss, 1914

Map measurer

"By use of an instrument called a map measurer, set the hand on the face to read zero, roll the small…