Ordnance Survey Flush Bracket
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- Опубликовано: 10 сен 2022
- This is a video is of a home made OS Flush Bracket and how it was used by the surveyors for the 2nd and 3rd (England and Wales) Geodetic Levelling Periods from 1912-21 and 1950-60 plus on triangulation pillars from 1936-62.