
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1775
1830 (original); 1967 (model)
1846
1815-1825
1771-1830
1801-1838
1795-1805
1829
1822
1780
1801-1830
1847-1848
1821
1775
circa 1842
1829
1801
1801-1830
1837
1794
1842
1842
1832
1845
1798
1842
1797
1805
1800
1780
1783-1800
1830
1795
circa 1808
1840
1785-1795
1771-1800
1810-1840
1810-1840
1771-1830
1835
1785
1837
1845
1776-1780
1776-1780
1776-1780
1848
1830-1840