*waywiser*

n. [ Cf. G. wegweiser a waymark, a guide; weg way + weisen to show, direct. ] An instrument for measuring the distance which one has traveled on the road; an odometer, pedometer, or perambulator. [ 1913 Webster ]

The waywiser to a coach, exactly measuring the miles, and showing them by an index. Evelyn. [ 1913 Webster ]