I have always been fascinated by the odd and the obscure. And most especially the lost and forgotten. So when I learnt that there was a very unusual relic from the past hiding on the grounds of Falmouth Hospital I was determined to find out more.

I first came across the Meridian Stone in a book about the history of Falmouth . . .

“1836 – Meridian Stone placed in field near Beacon”

– Old Falmouth, Susan Gay, 1903

Initially I presumed that it must have been destroyed because it was erected when Falmouth was a very different town from the one we know today. Not only was it a bustling harbour with ships from across the globe coming and going but in the 1830s the hilltop on which it now stands was still a field on the outskirts of the town, devoid of houses.

In fact, its elevated location was chosen because it once afforded a clear line of sight all the way to St Keverne Church on the Lizard some twenty miles away. And this view was the reason for the stone’s position.

Eliminating Inaccuracy

In 1836 the Royal Cornwall Polytechnic Society, ever the hub of industrial innovation and inquiring minds, announced their intention to provide a means for the “accurate determination of the true meridian”.

The plan was not just for show, science just for the sake of science, knowing this information was of particular importance to mine surveyors, it enabled them to calibrate their compasses and dials. This accuracy had the potential to save lives.

Magnetic north varies through time and location and therefore any surveys generated using only magnetic readings would be subject to an increasing degree of error, which in a mining context could prove fatal.

The Society planned to eliminate such inaccuracies, which could result in accidents and costly mistakes, by creating a means by which all such tools could be regularly checked against a fixed point or line.

“Before this Report shall be the hands of the public, your Committee hope to have supplied desideratum long wanted, by the accurate determination of the true meridian. Thus will furnished standard by which the variation of the magnetic, from the true meridian, may readily and any change in the declination of the needle easily detected. By it compasses and other mathematical instruments may accurately adjusted ; and Mine Agents and Surveyors will enabled to laydown their plans the true meridian.—The spire of St. Keverne Church has been fixed on, as the southern extremity of the line and it is intended to erect a granite pillar in field to the westward of Beacon Hill, to mark its other extremity near Falmouth. This will give a base line of about 40,000 feet, and it hoped that it will be continued through the County to the Bristol Channel.” – Royal Cornwall Gazette, 16th June 1837

The Stone

The four-sided pillar of dressed granite was to be erected on the westward side of Beacon Hill, positioned on the meridian, an imaginary north – south line, leading through St Keverne Church tower thus providing a calibration tool. In June 1837 the Royal Cornwall Gazette wrote that the Meridian Stone would “give a base line of about 40,000 feet”. Each side of the stone was engraved with one of the letters of the principal points of the compass and the flat top had a hole drilled into it.

Mining surveyors would then come to Beacon Hill, place their dials in or over the hole in the centre of the stone and align their devices precisely on St Keverne Church tower in the distance.

By this means the difference between true and magnetic north could be measured and the dial recalibrated accordingly. They could then return to their work safe in the knowledge that their equipment was giving an accurate reading.

Subsequently however it was discovered that there was also a difference between magnetism at the surface and magnetism underground and so the stone may have only been in use for a relatively short period.

There are other similar stones – The Altenberg meridian stones in Germany were set up in 1852 by surveyor Fr. J. Weiß for the same purpose as the one in Falmouth but some 15 years after the RCPS erected theirs.

Since the Meridian Stone was conceived the landscape around it has changed completely and the stone itself is now surrounded by development and undergrowth. However amazingly it still remains in its original position and it became a scheduled monument in 2008. The reasons for its designation highlight this humble monument’s national importance. It represents a tangible example of the scientific philanthropy of the 19th century, the importance of the mining industry in this part of the UK and it is thought to be the earliest surviving surveying stone (or base station) in the country, possibly the oldest of its kind anywhere in the world.

So the Falmouth Meridian Stone may have lost its view, its purpose may have become obsolete and it may now be hidden away in bushes but it appears to be entirely unique. And that, to my mind, makes it rather special!

Visiting the stone – Directions

The stone lies beside a footpath that runs alongside the hospital grounds. If you enter the path from Trescobeas Road the stone is roughly 25m up on the right hand side behind a metal fence.

Further Reading

The Mystery of Wheal Trewavas Mine

Falmouth’s Mystery Pyramid – the Killigrew Monument

Little Dennis Fort – Pendennis Point, Falmouth

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