Point of Reference

Bench mark on the former Methodist Church in East Street

Bench marks were used during the period of 1912 to 1921 as a point of reference for a measurement by Ordnance Survey surveyors.  These chiseled horizontal marks that surveyors made in walls, or permanent stone structures, consisted of an arrow below a horizontal line into which an angle iron could be placed for a leveling rod. These marks were introduced to record the height above their standard reference point of sea level at Newlyn in Cornwall.  If the exact height of a Bench mark is known, it follows that the exact height of a neighbour can be established, by measuring the difference in height with the process of spirit levelling. This all happened before the GPS satellite system took over.

The photograph above is of a Bench mark on the corner of a wall on the former Methodist Church in East Street.  There are two more known in the town.  One is chiseled into the wall of 38 High Street (Lamberts Yard) and another can be found on the wall of 10 Bordyke.

Is anyone is aware of further Benchmarks in Tonbridge?