Just a guess scouse smurf, but the space beneath the "ft in" letters, it looks like a panel for sliding a plaque into? Maybe the depth in feet and inches to the cable was recorded there - which would vary from sign to sign.Originally Posted by scouse smurf
My best guess anyway?
It's an ordnance survey benchmark.
So its a marker to say theres a joint in the telephone line ...
Cheers all, Mart
A permanently affixed mark that establishes the exact elevation of a place; used by Surveyors in measuring site elevations, or as a starting point for Surveys.
Obviously not used in the modern day anymore, but the slot was where they positioned their instrument. (ooer missus)
http://benchmarks.ordnancesurvey.co....663779::NO:3::
Its round the corner from you Mark !
I've seen a fair few around and about. There's an OS benchmark etched on the obelisk by Doddy's house too.
East Prescot Road by the Knotty Ash Medical Centre?
On Liverpool Docks - they used to use ODS [Old Dock Sill] as an established datum. Wiki here.
I wonder whether any of these ODS datum markers remain?
ps. the Old Dock site is open to the public from today.
Its on E Prescot Rd behind the Aldi.
Thanks for these links.
If the symbol isn't exactly a benchmark, it's something similar.
The space is for the location for whatever this stone refers to.
I'm still mystified.
Hope somebody can supply the answer
It's definately an OS benchmark. Here's a bit more info...
http://en.wikipedia.org/wiki/Benchmark_(surveying)
Here's a snippet of how they measure the tides using a benchmark and it started in Liverpool...
The main bench mark is near Tolcarne School and frequent checks are made to determine if there is the slightest shrinkage between the observatory and the main bench mark. By deducting 9.9 feet from the Ordnance Datum the recordings on the admiralty chart for Mount's Bay can be arrived by. Newlyn was chosen as the base for the tidal observatory because, after many years of constantly monitoring the tides, it was found to be the most constant. The first O.S. selected datum point in 1840 was 100 feet below a bench mark on St. John's church, Liverpool, and a few years later at the Victoria Docks where tidal observations were taken every five minutes. From 1844 the approximate sea level was adopted from the Liverpool datum and was the accepted reading form 80 years.
Ha,Ha, it's for the little people like A.D.W.
What made me wonder if it wasn't exactly a benchmark was one of your earlier links which mentions a horizontal line above the arrow, on a benchmark.
Your link above says what the horizontal line was for (which I didn't know).
Quote:
The term benchmark originates from the chiseled horizontal marks that surveyors made in stone structures, into which an angle-iron could be placed to form a "bench" for a leveling rod, thus ensuring that a leveling rod could be accurately repositioned in the same place in future. These marks were usually indicated with a chiseled arrow below the horizontal line.
The height of a benchmark is calculated relative to the heights of nearby benchmarks in a network extending from a fundamental benchmark, a point with a precisely known relationship to the level datum of the area, typically mean sea level. The position and height of each benchmark is shown on large-scale maps.
The terms "height" and "elevation" are often used interchangeably, but in many jurisdictions they have specific meanings; "height" commonly refers to a local or relative difference in the vertical (such as the height of a building), whereas "elevation" refers to the difference from a nominated reference surface (such as sea-level, or a mathematical/geodetic concept known as the geoid).
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