
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1815-1825
1795-1805
1829
1822
1780
1821
1829
1801
1794
1798
1797
1805
1800
1780
1783-1800
1795
circa 1808
1785-1795
1785
2000-100 BCE
1813
1826
1808
1812
1805-1815
1783
1785
1793-1803
circa 1805
1807
1782-1793
1785-1790
1784
1815
1784
1815
1795-1810
1893-4
1863-7
1791
1808
1786
1800
1807
1787
1821
1790
1796
1794