Levelling Homepage Ordnance Survey's
Levelling
of Great Britain		 [1GL, 2GL Abstract]
[1GL, 2GL Transcription]		 [Timeline]
[FBM List]		 TrigTools

Files Held at Kew

'Levelling' Files

[General Levelling Files - 1GL - 2GL] (All | Viewed)

[Summary of Records of the Ordnance Survey of Great Britain]

Filter: (+) to show results from that Record Series, (-) to hide details from that Record Series
RefSourceDateNotes
+ - OS 45Ordnance Survey of Great Britain: Director General: Manuals and Instructions1882-1978
OS 45/82Levelling handbook: 2nd edition1963-1974
+ - OS 1Ordnance Survey: Central Registry: Registered Files (SO and CR Series)1959-1988
OS 1/131Levelling of the Ouse Catchment Area1940-1942
OS 1/134Re-levelling of Greater London1927-1948Some interesting maps and abstracts
OS 1/182Levelling: errors.1932-1944
OS 1/260Standard Tests for Triangulation and Levelling trades.1946 - 1951
OS 1/280Adjustment of the third geodetic levelling of Great Britain.1956 - 1961
OS 1/281Geodetic levelling: Scotland1926 - 1949
OS 1/315Levelling1931 - 1953
OS 1/323Investigation by Treasury Organisation and Methods Division - Trig and Levelling Division1945 - 1947
OS 1/535Island of Jersey: miscellaneous levelling records1912-1935
OS 1/907Hydrostatic levelling Bacton to North Sea gas rig1967-1972
OS 1/908Hydrostatic levelling Bacton to North Sea gas rig: second1969
OS 1/912Levelling: Cyprus1968-1969
OS 1/913Levelling: Isle of Man1968-1971
OS 1/969Levelling instruments: theodolites, etc1954-1956
OS 1/1086Levelling1953-1958
OS 1/1087Levelling1958-1967
OS 1/1139Third geodetic levelling: Scotland1956-1964Very Interesting Maps, of E&W too!
OS 1/1143Levelling: systematic errors1958-1965
OS 1/1144Levelling: standard line1958-1966
OS 1/1202Oceanographic Meteorological Research Committee: fixed station; tide gauge in relation to third geodetic levelling1961-1963
OS 1/1218International Association of Geodesy: European levelling net1960-1963
OS 1/1246Tertiary levelling: second cycle computing and adjustment1961-1963
OS 1/1254Third geodetic levelling: publication1958-1970Some interesting Stuff
OS 1/1270International Association of Geodesy: European Levelling Network1962-1963
OS 1/1311Adjustment of third geodetic levelling1956-1960
OS 1/1336Hydrostatic levelling1965-1970
OS 1/1406Adjustment of 3rd geodetic levelling of Great Britain1967-1972
OS 1/1482International Association of Geodesy : European levelling net1970 Jan 01-1974 May 01
OS 1/1589International Association of Geodesy: European Levelling Networks1959 Oct 01-1959 Oct 31
OS 1/1590Review of basic scale surveys and levelling service - Consultative questionnaires: responses and correspondence1973 May 03-1973 Nov 12
OS 1/1603Publication of professional paper on 3rd geodetic levelling of Great Britain (not published)1973 Dec 17
OS 1/1658Review of basic scale survey and levelling service policy1980 Jul 28
OS 1/10/1Levelling and contouring: notes1867
OS 1/10/2Secondary system of levelling report
OS 1/10/3Initial levelling: revision1911-1921
OS 1/10/4Whewell's levelling: Bristol Channel to English Channel1924-1927IanR
+ - OS 11Ordnance Survey: Central Registry: Policy Paper Files (PP Series)1947-1982
OS 11/37Levelling1950-1969
+ - OS 14Ordnance Survey: Central Registry: Experiment Files (E Series)1950-1988
OS 14/54Minor experiments : trigonometry and levelling including reports1968 Feb 01-1969 Nov 24
OS 14/60Hydrostatic levelling1965 Dec 01-1972 Mar 31
OS 14/62Levelling equipment :field tests and reports of various automatic setting levels1968 Dec 01-1977 Mar 31
OS 14/68Fourth geodetic levelling : correspondence and reports1971 Jun 01-1977 Oct 31
OS 14/81Fourth Geodetic Levelling: proposed Ordnance Survey and Institute of Oceanographic Sciences experiment to compare geodetic and hydrodynamic levelling techniques1977 Oct 14-1980 May 21
OS 14/82Geodetic levelling techniques: includes National Geodetic Survey paper 'Refraction Errors in Levelling - NGS Test Results'; report on a visit to the National Survey of Sweden to view a motorised geodetic levelling production unit in operation1980 Jul 01-1981 Sep 16
+ - OS 13Ordnance Survey: Directorate of Field Survey: Branch Files1960-1981
OS 13/99Levelling Investigations and Coastal Geodesy1960 Sep 01-1977 Aug 01
+ - OS 16Ordnance Survey: Trigonometrical and Levelling Divisions: Second Geodetic Levelling, Specimen Record ...1943-1950
OS 16/1Forward and back levelling1950
OS 16/2Forward levelling1950
OS 16/3Back levelling1950
OS 16/4Forward levelling1950
OS 16/5Forward levelling1950
OS 16/6Forward levelling1950
OS 16/7Forward levelling1950
OS 16/8Forward levelling1950
OS 16/9Forward levelling1950
OS 16/10Forward levelling1950
OS 16/11Forward levelling1950
OS 16/12Forward and back re-levelling1950
OS 16/13Forward levelling1950
OS 16/14Forward levelling1950
OS 16/15Forward levelling1950
OS 16/16Forward levelling1950
OS 16/17Forward re-levelling1950
OS 16/18Forward re-levelling1950
OS 16/19Forward and back re-levelling1950
OS 16/20Forward and back re-levelling1943
OS 16/21Forward and back re-levelling1943
OS 16/22Forward and back re-levelling1943
OS 16/23Forward levelling1943
OS 16/24Forward levelling1943
OS 16/25Forward and back re-levelling1943
OS 16/26Forward levelling1943
OS 16/27Forward re-levelling1943
OS 16/28Forward and back levelling1943
OS 16/29Forward and back levelling1943
OS 16/30Forward levelling1943
OS 16/31Forward levelling1943
OS 16/32Forward and back re-levelling1943
OS 16/33Forward levelling1943
OS 16/34Forward levelling1943
OS 16/35Forward and back re-levelling1943
OS 16/36Forward levelling1943
OS 16/37Forward and back re-levelling1943
OS 16/38Forward and back re-levelling1943
+ - OS 17Ordnance Survey: Trigonometrical and Levelling Divisions: Liverpool Levelling Books and Abstracts1862-1925
OS 17/1Place: Hampshire Type of levelling: Detail1865
OS 17/2Place: Hampshire Type of levelling: Detail1866
OS 17/3Place: Hampshire and Wiltshire Type of levelling: Detail1866
OS 17/4Place: Nottingham Type of levelling: Town1879
OS 17/5Place: Winchester, Dorking, Chertsey and Petersfield Type of levelling: Town1869
OS 17/6Place: Hampshire Type of levelling: Branch[1863]
OS 17/7Place: Bridgewater to Tavistock Type of levelling: Initial1883
OS 17/8Place: Lyme Lyme Regis to Southampton Type of levelling: Initial and Branch1862
OS 17/9Place: Cornwall Type of levelling: Initial[1878-1879]
OS 17/10Place: Hampshire Type of levelling: Initial[1864]
OS 17/11Place: Somerset Type of levelling: Branch1887
OS 17/12Place: TavistockTavistock, Dartmouth, Bideford, Barnstaple and Totnes Type of levelling: Town1882-1886
OS 17/13Place: Merioneth and Montgomery Type of levelling: Branch1885
OS 17/14Place: Yorkshire Type of levelling: Initial1888
OS 17/15Place: Yorkshire Type of levelling: Initial1888
OS 17/16Place: Darlington and environs Type of levelling: Town/InitialUndated
OS 17/17Place: Darlington and environs Type of levelling: Town/InitialUndated
OS 17/18Place: Hartlepool and environs Type of levelling: Town/InitialUndated
OS 17/19Place: Scarborough, Middlesbrough Type of levelling: Town1891-1892
OS 17/20Place: Stockton-on-Tees Type of levelling: Town1891-1892
OS 17/21Place: Cornwall, Devon Type of levelling: Branch1883
OS 17/22Place: Devon, Somerset Type of levelling: Initial1883-1884
OS 17/23Place: Devon Type of levelling: Branch1883-1884
OS 17/24Place: Devon Type of levelling: Branch1883-1884
OS 17/25Place: Devon, Somerset Type of levelling: Branch1884-1885
OS 17/26Place: Montgomery, Radnor and Cardigan Type of levelling: Branch1884-1885
OS 17/27Place: Devon Type of levelling: Branch1864-1867
OS 17/28Place: Carmarthen Type of levelling: Branch1884-1885
OS 17/29Place: Towns in Dorset and Somerset Type of levelling: Town/Branch1885-1887
OS 17/30Place: Devon Type of levelling: Branch1885-1886
OS 17/31Place: Devon, Somerset Type of levelling: Branch1885-1886
OS 17/32Place: Dorset Type of levelling: Branch1885-1886
OS 17/33Place: Dorset and Devon Type of levelling: Branch1886-1887
OS 17/34Place: Towns in Devon and Somerset Type of levelling: Town1886
OS 17/35Place: Dorset Type of levelling: Branch1886-1887
OS 17/36Place: Hampshire Type of levelling: Sectional1895
OS 17/37Place: Newcastle-upon-Tyne and environs Type of levelling: Town1895
OS 17/38Place: Sunderland, Durham Type of levelling: Sectional1895-1896
OS 17/39Place: Durham, Northumberland Type of levelling: Branch1895
OS 17/40Place: Durham Type of levelling: Branch1895
OS 17/41Place: Northumberland Type of levelling: Branch1895
OS 17/42Place: Durham Type of levelling: Branch1895-1896
OS 17/43Place: Hampshire Type of levelling: Sectional1896
OS 17/44Place: Military sites Type of levelling: Tidal/Special1896-1924
OS 17/45Place: Durham Type of levelling: Branch1896-1901
OS 17/46Place: Roxburgh and Berwick Type of levelling: Sectional1897
OS 17/47Place: Berwick and Northumberland Type of levelling: Sectional1897
OS 17/48Place: Berwick and Dumfries Type of levelling: Sectional1898
OS 17/49Place: Staffordshire Type of levelling: Revisional/Initial/Branch1897-1900
OS 17/50Place: Wiltshire Type of levelling: Sectional1900-1901
OS 17/51Place: Aberdeen and Banff Type of levelling: Sectional1900-1901
OS 17/52Place: Dorset Type of levelling: Sectional1900-1901
OS 17/53Place: Devon Type of levelling: Sectional1903-1904
OS 17/54Place: Norfolk, Suffolk Type of levelling: Sectional1903-1904
OS 17/55Place: Devon Type of levelling: Sectional1904
OS 17/56Place: Devon Type of levelling: Sectional1904-1905
OS 17/57Place: Devon Type of levelling: Sectional1904-1905
OS 17/58Place: Devon, Cornwall Type of levelling: Sectional1905
OS 17/59Place: Cornwall Type of levelling: Sectional1905-1906
OS 17/60Place: Haddington, Berwick and Peebles Type of levelling: Sectional1906-1907
OS 17/61Place: Hampshire Type of levelling: Sectional1906-1907
OS 17/62Place: Cheshire Type of levelling: Initial/Branch1907
OS 17/63Place: Cheshire Type of levelling: Branch1907
OS 17/64Place: Hampshire Type of levelling: Sectional1907
OS 17/65Place: Hampshire Type of levelling: Sectional1907-1908
OS 17/66Place: Hampshire Type of levelling: Sectional1908
OS 17/67Place: Hampshire Type of levelling: Sectional1908-1909
OS 17/68Place: Hampshire Type of levelling: Sectional1909-1922
OS 17/69Place: Berkshire Type of levelling: Revisional1910-1911
OS 17/70Place: Durham Type of levelling: Branch1914-1915
OS 17/71Place: Yorkshire, North Riding Type of levelling: Sectional1910
OS 17/72Place: Warwickshire, Staffordshire Type of levelling: Branch1912-1913
OS 17/73Place: Nottinghamshire Type of levelling: Revisional1912-1913
OS 17/74Place: Yorkshire, Durham Type of levelling: Revisional1913
OS 17/75Place: Northumberland, Durham Type of levelling: Branch1913
OS 17/76Place: Northumberland Type of levelling: Revisional1915
OS 17/77Place: Coastal erosion Type of levelling: Special1919-1920
OS 17/78Place: Staffordshire, Warwickshire and Worcestershire Type of levelling: Tertiary1912-1915
OS 17/79Place: Staffordshire Type of levelling: Tertiary1912-1914
OS 17/80Place: Staffordshire Type of levelling: Tertiary1912-1915
OS 17/81Place: Shropshire Type of levelling: Tertiary1875-1902
OS 17/82Place: Shropshire Type of levelling: Tertiary1880-1902
OS 17/83Place: Shropshire Type of levelling: Tertiary1881-1902
OS 17/84Place: Shropshire Type of levelling: Reclosing1874-1901
OS 17/85Place: Shropshire Type of levelling: Reclosing1883
OS 17/86Place: Suffolk Type of levelling: Reclosing1873-1903
OS 17/87Place: Shropshire Type of levelling: Reclosing1875-1925
OS 17/88Place: Shropshire Type of levelling: Reclosing1874-1901
OS 17/89Place: Shropshire Type of levelling: Reclosing1874-1902
OS 17/90Place: Yorkshire Type of levelling: Reclosing1905-1918
OS 17/92Place: Yorkshire Type of levelling: Reclosing1908
OS 17/93Place: Dorset, Hampshire Type of levelling: Tertiary (reclosing)1866-1908
OS 17/94Place: Suffolk Type of levelling: Reclosing1880-1903
OS 17/95Place: Suffolk Type of levelling: Reclosing1898-1903
OS 17/96Place: Yorkshire, East Riding Type of levelling: Reclosing1890-1908
+ - OS 18Ordnance Survey: Directorate of Field Survey: Cambridge Radio Telescope Observations1969-1970
OS 18/6Geodetic levelling book: forward1969
OS 18/7Geodetic levelling book: back1969
OS 18/8Geodetic levelling book: forward and back1969
OS 18/9Geodetic levelling book: forward; metric1969
OS 18/10Geodetic levelling book: back; metric1969
OS 18/11Geodetic levelling book: forward1969
OS 18/12Geodetic levelling book: back1969
OS 18/13Geodetic levelling book: back1969
OS 18/14Geodetic levelling book: forward1969
OS 18/15Geodetic levelling book: forward and back; third series1970
OS 18/16Geodetic levelling book: forward and back1969
OS 18/17Geodetic levelling book: forward and back1970
OS 18/18Geodetic levelling book: forward; metric1970
OS 18/19Geodetic levelling book: back; metric1970
OS 18/20Geodetic levelling book: forward and back1970
OS 18/21Geodetic levelling book: forward and back1970
OS 18/22Geodetic levelling book: forward and back; staff comparison readings1970
OS 18/23Geodetic levelling book: forward and back1970
OS 18/24Geodetic levelling book: back; third series1970
OS 18/25Geodetic levelling book: forward; third series1970
OS 18/26Geodetic levelling book: forward and back; third series1970
OS 18/27Geodetic levelling book: forward and back1970
OS 18/28Geodetic levelling book: forward and back1970
OS 18/29Geodetic levelling book: forward and back1970
OS 18/30Geodetic levelling book: forward and back1970
OS 18/31Geodetic levelling book: back1970
OS 18/32Geodetic levelling book: forward; metric, third series1970
OS 18/33Geodetic levelling book: back; metric, third series1970
OS 18/34Geodetic levelling book: forward and back, stock bracket experiment1970
+ - OS 54Ordnance Survey: Trigonometrical and Levelling Divisions: Levelling Books and Abstracts1874-1954
OS 54/239A 577 Special levelling (Wigton 1949) (Wiltshire 1949)1949 Jan 01 - 1949 Dec 31
OS 54/246A 584 Special levelling (Chatham - Dunkirk 1950) (Sheffield 1950) (Yorkshire 1950)1950 Jan 01 - 1950 Dec 31
OS 54/258A 596 Special levelling (Eskmeals 1952) (Aberporth 1952)1952 Jan 01 - 1952 Dec 31
+ - OS 3Ordnance Survey: Miscellanea1755-1993
OS 3/76The levelling system of Great Britain1950
OS 3/79Matters arising from the completion of the third geodetic levelling of Wales by Major J. Kelsey, RE: prepared for Commonwealth Survey Officers' Conference 19591959
OS 3/422'Levelling Instrument WILD NII: Description and Instructions for use': Author and publisher Surveying Instruments Supply Company Limited, Henry Wild, Heerbrugg SwitzerlandUNDATED-UNDATED
OS 3/437'Report on the Levelling Network of London and Kent': Author and publisher Ordnance Survey1932 Jan 01-1932 Dec 31
OS 3/439'Report on the Levelling Network of Wales': Author and publisher Ordnance Survey1932 Jan 01-1932 Dec 31
OS 3/281Draft report on the work of the Levelling Division, 1921-1926[1926]
+ - OS 5Ordnance Survey: Maps and Plans1777-1971
OS 5/188Geodetic levelling: state of work 8 Aug 19141914
OS 5/189Geodetic levelling: stations1914
OS 5/191Geodetic levelling: state of work 31 Mar 19191919
OS 5/192Geodetic levelling: lines in London area1932Basic Map
OS 5/193Index map on initial levelling in Scotlandundated
+ - OS 51Ordnance Survey: Photographs and Pictorial Images1950-1969
OS 51/90Ridgeway Base 1937 short levelling staff: baseline measurement - photograph showing a short levelling party1950 Jan 01-1968 Dec 31
OS 51/176Plane mirror: photograph showing the mounting, central stop and levelling screws1950 Jan 01-1968 Dec 31
OS 51/402First Geodetic Levelling England and Wales 1840-1860: map showing the levelling. Mean date January 1950 based on a tidal pole fixed at the entrance to Victoria Dock in London 1844. Plate I in the book 'Second Geodetic Levelling of England and Wales 1912-21' by Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/403First Geodetic Levelling Scotland 1844-1859: map showing the levelling. Mean date January 1950 based on a tidal pole fixed at the entrance to Victoria Dock in London 1844. Plate I in the book 'Second Geodetic Levelling of England and Wales 1912-21' by Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolf and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/404Second Geodetic Levelling England and Wales 1912-21: map showing the levelling. Mean date January 1916. Tidal stations were fixed at Newlyn (Cornwall), Felixstowe (Suffolk) and Dunbar and 115 fundamental bench marks laid across the country. Subsequent flush brackets also added to the primary lines.1950 Jan 01-1968 Dec 31
OS 51/405Second Geodetic Levelling Scotland 1936-52: map showing levelling (View) (View)1950 Jan 01-1968 Dec 31Second Geodetic Levelling Scotland 1936-52: map showing levelling
OS 51/407Second Geodetic Levelling showing difference between Newlyn and Liverpool: map showing the differences of level throughout England between the old levels based on the old Ordnance Survey Datum and the new geodetic levels based on mean sea levels at Newlyn (Cornwall).1950 Jan 01-1968 Dec 31
OS 51/408Third Geodetic Levelling: map showing levelling of Great Britain showing tidal stations, fundamental bench marks, the second levelling of Scotland and the third levelling of England and Wales labelled plate IV source unknown, circa 1950s (View) (View)1950 Jan 01-1968 Dec 31Third Geodetic Levelling
OS 51/409Connections of tidal stations to levelling networks: map of Britain and Europe showing the connection of tidal station to the European Levelling Network, circa 1960 (View) (View)1950 Jan 01-1968 Dec 31Very Little Detail
OS 51/412Newlyn observation: split shot showing a photograph of Newlyn (Cornwall) from the air and a map of Newlyn at 6 inches to 1 mile scale. Plate XIIa in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/413Tidal observatory Dunbar: diagram showing the plan, section and elevation and view of the tidal observatory at Dunbar (East Lothian). Plate XII in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/414Tide gauge: front view of an automatic tide gauge. Plate XIII in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/415Tide gauge: side view of an automatic tide gauge. Plate XIII in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/416Fundamental bench mark diagram: diagram showing plan and section dated 1913. Plate X in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/419Fundamental benchmark being opened up: process of Third Geodetic Levelling, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/420Fundamental benchmark checking between surface mark: process of Third Geodetic Levelling, circa 1950s. Used in the book 'OS - Mapmakers to Britain since 1791' by Tim Owen and Elaine Pilbeam 19921950 Jan 01-1968 Dec 31
OS 51/421Leveller observing height between fundamental and surface mark: process of Third Geodetic Levelling, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/422Shell deep benchmark: levelling - diagram showing a section through a shell permanent deep bench mark1950 Jan 01-1968 Dec 31
OS 51/423Flush bracket showing detachable bracket: levelling - diagram showing the section and front view of bracket, dated 1913. Plate XI in the book 'Second Geodetic levelling of England and Wales 1912-21' by Colonel Sir Charles Close 1921 with chapters written by Lieutenant-Colonel A J Wolff and Mr H L P J Jolly (View)1950 Jan 01-1968 Dec 31
OS 51/424Levelling marks and brackets: display of various marks and brackets1950 Jan 01-1968 Dec 31
OS 51/427Levelling: use of a Cooke Troughton and Sims 5400 level, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/428Geodetic levelling staff on flush bracket: use of staff on the side of a brick wall, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/429Geodetic levelling staff on shoe: levelling - staff mounted on a 'shoe' in an urban setting, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/430Geodetic levelling party at work: general view, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/431Geodetic levelling - page of levellers field book: completed in the field, dated 29 November 19501950 Jan 01-1968 Dec 31
OS 51/432Geodetic levelling - page of levellers field book completed in office: dated 1 February 19471950 Jan 01-1968 Dec 31
OS 51/433Geodetic levelling abstract: Duns Common - Kelso (Scotland), dated August 19521950 Jan 01-1968 Dec 31
OS 51/436Tertiary levelling using S400 level: use of a Cook, Troughton and Simms S400 spirit level, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/437Tertiary levelling staff holder: levelling staff mounted on a 'shoe' and staff holder, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/438Tertiary levelling party at work: showing leveller and staff holder, circa 1940s, 1950s1950 Jan 01-1968 Dec 31
OS 51/439Tertiary levelling - page of levellers field book: specimen page completed in the field, dated 24 October 19461950 Jan 01-1968 Dec 31
OS 51/440Tertiary levelling - page of levellers field book completed in office: specimen page,dated 24 October 19461950 Jan 01-1968 Dec 31
OS 51/441Tertiary levelling abstract: Oxfordshire, dated November 19521950 Jan 01-1968 Dec 31
OS 51/442Relevelling London staff holder in Oxford Street: Third Geodetic Levelling, circa mid 1950s1950 Jan 01-1968 Dec 31
OS 51/443Relevelling London leveller in Oxford Street: Third Geodetic Levelling. circa mid 1950s1950 Jan 01-1968 Dec 31
OS 51/444Relevelling London staff holder in Oxford Street: Third Geodetic Levelling, circa mid 1950s1950 Jan 01-1968 Dec 31
OS 51/452Calculating machines Facit, hand: used for triangulation and levelling computations in Survey Computations branch, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/453Calculating machines Victor Electric: used for levelling computations in Survey Computations Branch, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/454Calculating machines National Cash Register: used for levelling computations and benchmarks in Survey Computations Branch, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/455Calculating machines view of level computers: Survey Computations - general view of staff working on levelling computations, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/462Sorter: Survey Computations - view of a punch card sorter used in levelling computations, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/463420 Accounting Machine: Survey Computations - view of an IBM 420 accounting machine used in levelling computations, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/466Levelling computations flow chart 1-3: Survey Computations - diagram showing the flow chart between stages 1-3 of the work required and machinery used in levelling computations, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/467Levelling computations flow chart 4-6: Survey Computations - diagram showing the flow chart between stages 4-6 of the work required and machinery used in levelling computations, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/468Levelling computations flow chart 7: Survey Computations - diagram showing the flow chart for stage 7 of the process, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/1389Index map of initial levelling of England and Wales: levelling carried out between 1841 and 1860, used in 'Ordnance Survey Mapmakers to Britain' by Owen and Pilbeam1950 Jan 01-1968 Dec 31
OS 51/1429Staff on angle iron: levelling staff fixed onto a Bench Mark in the snow1950 Jan 01-1968 Dec 31
OS 51/1430Leveller taking reading: military surveyor levelling with level mounted on a tripod, circa 1910s1950 Jan 01-1968 Dec 31
OS 51/1433Fundamental Bench Mark: plan and section. Plate X in 'Second Levelling of England and Wales 1912 - 1921'1950 Jan 01-1968 Dec 31
+ - OS 1Ordnance Survey: Central Registry: Registered Files (SO and CR Series)1959-1988
OS 1/284Fundamental Bench Marks1927 - 1953IanR
OS 1/339Stable Bench Marks in mining areas1933 - 1955
OS 1/1407Bench mark lists: policy1968-1971
+ - OS 3Ordnance Survey: Miscellanea1755-1993
OS 3/91Origin of the broad arrow (used by the Ordnance Survey as Bench Mark which indicates the point to which levels have been observed)1964
+ - OS 51Ordnance Survey: Photographs and Pictorial Images1950-1969
OS 51/1396The Geodetic Network: showing tidal stations and fundamental Bench Marks across England and Wales1950 Jan 01-1968 Dec 31
OS 51/417Fundamental buried benchmarks: exposed benchmarks, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/418Fundamental benchmark showing railings and pillar: showing surface mark, circa 1950s1950 Jan 01-1968 Dec 31
OS 51/445Benchmark list: list of all benchmarks that fall on 1:2500 sheet SY 11881950 Jan 01-1968 Dec 31
OS 51/1201Description of Height Control Point: diagram of point 23155G, Rhyl, Wales, dated 19591950 Jan 01-1968 Dec 31

documents we have but not in list above:

RefSourceDateNotes
OS 1/1266IanR
OS 1/818IanR
OS 18/5IanR
OS 2/160Took Copies of Selected Stations
OS 2/161Took Copies of Selected Stations
OS 2/26Took Copies of Selected Stations
OS 5/187basic map
OS 51/1493Original Cover Design Only
OS 51/28 (View)Map of Secondary Triangulation blocks Scotland
OS 51/29 (View)Map of Secondary Triangulation blocks England and Wales
OS 54/127IanR (part)
OS 54/136IanR (part)
OS 54/143IanR
OS 54/144IanR
OS 54/145IanR
OS 54/148Have copy of Conway to Caernarvon
OS 54/154Have copy of Caernarvon to Trawsfynydd
OS 54/155IanR
OS 54/158Have copy of Trawsfyndd to Wrexham
OS 54/160IanR
OS 54/164IanR
OS 54/175IanR
OS 54/188IanR
OS 54/206RoyB has a full copy
OS 54/213IanR
OS 54/31IanR
OS 54/466Little of interest (no FB's)