Description

FALMOUTH

843-1/0/10016 FALMOUTH HOSPITAL
09-JUL-08 MERIDIAN STONE

II
Meridian stone erected in 1837 by the Royal Cornwall Polytechnic Society. Large dressed block of granite with narrow chamfered step. The stone has four principal faces and a flat top with a small central hole. Each face bears an inscribed letter representing the principal points of the compass.

History: The stone was positioned on the meridian leading through St Keverne Church tower to provide a calibration tool for miners' surveying compasses known as dials. Magnetic north varies through time and therefore any surveys generated using only magnetic readings would be subject to an increasing degree of error, which in a mining context could be fatal. As a measure to reduce the inaccuracies, the Society erected this stone. Mining surveyors placed their dials in or over the hole in the centre of the stone and aligned the device precisely on St Keverne Church tower. By this means the difference between true and magnetic north could be measured and the dial calibrated accordingly. In subsequent years it was discovered that there were also difference between magnetism at the surface and underground and the stone may therefore have been used for a relatively short period.

A plaque formerly attached to the western face read "This pillar was erected in the Meridian of St Keverne by The Royal Polytechnic Society of Cornwall in the year 1837".

SOURCES
Williams, J.B., Practical Geodesy, (1855), 193-205.
Hoskold, H.D., A practical treatise on mining, land and railway surveying, engineering, &c., (1863), 1-7.
http://gge.unb.ca/PhotoAlbum/1996/Jack/JackPillar.gif Accessed 28th May 2008
http://gge.unb.ca/MT/Events/Commemoration.pdf Accessed 28th May 2008

REASONS FOR DESIGNATION DECISION
The Falmouth Meridian Stone, is designated at Grade II for the following principal reasons:
* The stone survives well in its original position
* The stone retains its line of sight to St Keverne Church tower
* The stone played an important role in the development of compass calibration
* It may be the earliest surviving survey related base station
* It is associated with the internationally important C19 Cornish mining industry
* It represents tangible evidence of scientific philanthropy

Reasons for Listing

The Falmouth Meridian Stone, has been designated at Grade II for the following principal reasons:
* The stone survives well in its original position
* The stone retains its line of sight to St Keverne Church tower
* The stone played an important role in the development of compass calibration
* It may be the earliest surviving survey related base station
* It is associated with the internationally important C19 Cornish mining industry
* It represents tangible evidence of scientific philanthropy

External Links

• Historic England Listing
• Wikidata Q26671852

External links are from the relevant listing authority and, where applicable, Wikidata. Wikidata IDs may be related buildings as well as this specific building. If you want to add or update a link, you will need to do so by editing the Wikidata entry.

Recommended Books

• 
  Listed Buildings: The Law and Practice of Historic Buildings, Ancient Monuments and Conservation Areas
• 
  Sussex: West (Pevsner Architectural Guides: Buildings of England)
• 
  Oxfordshire: North and West (Pevsner Architectural Guides: Buildings of England)
• 
  Suffolk: West: The Buildings of England (Pevsner Architectural Guides) (Pevsner Architectural Guides: Buildings of England)
• 
  London 4: North: North v. 4 (Pevsner Architectural Guides: Buildings of England)
• 
  Harrow on the Hill: A photographic portrayal of listed buildings and structures (Historic Buildings Picture Guides)