
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
2000-100 BCE
1794
1799
1796-1797
1796-1798
circa 1800
1798
1797
1791
1800
1796
1800
1800
1794
1800
1800
1792
1795
1795
1800
1795
1795
1792
1792
1775-1799 (original); 1900-1907 (model)
1794
1772 (original); 1919 (model)
1797
4000-2001 BCE
1799
1792
1990-96
1791-1792
circa 1795
circa 1800
mid-1800s
1705-1737
1797
1800
1791
1799
1795
1800
1797
1990-95
1610; 1923
1642-1649 (original); 1883 (model)
1960-1979
1794