
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1642-1649 (original); 1883 (model)
1668; 1924
1990-96
1610; 1923
1772 (original); 1919 (model)
1794
2000-100 BCE
1791 - 1871
1990-95
1790
1705-1737
1790-1794
1790
1791-1792
1580-1588; 1930
4000-2001 BCE
circa 1795
300 BCE; 1905-1915
1960-1979
2050-1750 BCE
1789
1936
1789-1795
1791 - 1871
1791
2000-1001 BCE
1730-1760 (original); 1931-1939 (replica)
6000-5000BCE
100-1 BCE; 1501-1600; 1914
1600-1500 BCE (original); 1900-1914 (copy)
1795
1501-1600; 1972
1795 - 1865
1794
1976; 1776
1991-1783 BCE
1792
1795
700 BCE; 1931
1783; 1914
1794 - 1992
circa 3000 BCE
1777 (original); 1894 (model)
1789 - 1864
8500-2000 BCE
1791
1792
1790
1790