
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1795-1805
1821
1822
1801
1793-1803
1794
circa 1805
1798
1797
1893-4
1805
1800
1812
1805-1815
1795
circa 1808
1814
1792
2000-100 BCE
1813
circa 1810
1808
1790-1820
1810-1817
1807
1815
1815
1795-1810
1863-7
1791
1808
1800
1807
1821
1790
1796
1794
1800
1800
1800
1795-1805
1807
1812
1792
1795
1800
1790
1807
1802