BrownhillsBob's #365daysofbiking

On a bike, riding somewhere. Every day, rain or shine.

Posts tagged ‘Flush bracket’

#365daysofbiking Feeling flush



March 11th – I had time to spare so hopped onto the restored canal at Droitwich for a mooch. Just under the railway bridges in the last entry, I noticed this relic of the Ordnance Survey.

Flush Bracket 480 is one of a range of such brackets intended as mapmaker’s datums, the slots in which were for mounting surveying equipment at a known datum – in this case 28.7490m above sea level (the Newlyn Datum).

Now redundant as cartographer’s aids, these are more a historical curiosity than anything else, but I still get a buzz from spotting them in the wild.

You can find out more about this one here.

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from Tumblr

August 30th – Out for an afternoon spin, I came through Wall, just south of Lichfield. Just as I was approaching the junction of the old Watling Street and Wall Lane, I noticed that on the side of the old barn at Manor Farm, there was an Ordnance Survey Flush Bracket. This is a type of benchmark that was used for map surveying – in the notches on the plate, surveying equipment could be mounted at a height known to the surveyor, called a Datum, or benchmark. The flat tip of the arrow indicates the precise height  point, and this is benchmark reference S8958. 

I must have passed this wall hundreds of times and have never noticed this feature.