
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1791
1792
1792
1792
2000-100 BCE
1990-96
1705-1737
1791
1791-1792
1792
1772 (original); 1919 (model)
4000-2001 BCE
1936
300 BCE; 1905-1915
1792
1792
1792
30 CE
1791
1791
30 CE
1791
20-400
30-200
20-500
20-500
1972-3
1990-95
15/7/27
15/7/27
1840-160
circa 3000 BCE
3000 BCE
circa 3000 BCE
circa 3000 BCE
circa 3000 BCE
circa 3000 BCE
circa 3000 BCE
circa 3000 BCE
circa 2000 BCE
1792
2500 BCE
2000-1000
1792
1860-1715
circa 1800 BCE
1713-1750
1692-1730
1791