
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1794
1795
1792
2000-100 BCE
1791
1790
1794
1792
1795
1790
1795
1795
1790
1792
1790
1794
1772 (original); 1919 (model)
1705-1737
1791
1790-1794
1795
1790
circa 1795
1790
1791-1792
1990-96
1792
4000-2001 BCE
1936
1790
300 BCE; 1905-1915
1791
1774; 1923
1642-1649 (original); 1883 (model)
1730; 1967
1793
1794-03-03
1790-1793
1850-1899
1790-1794
2000-100 BCE
3000-2500 BCE
1793
1791
1793
1676; 1840-1865
1791
1794
1794