
Theodolite used for the Principal Triangulation of Great Britain
1791
1791
1795
1794
1798
1797
1805
1800
1783-1800
1795
circa 1808
1785-1795
1785
1808
1793-1803
circa 1805
1807
1785-1790
1784
1784
1795-1810
1863-7
1791
1808
1786
1800
1807
1787
1790
1796
1794
1800
1800
1800
1795-1805
1807
1792
1795
1800
1790
1807
1802
1795
1795
1790
1792
1792
1802
1790
1785-1795
1799-1802