Slide rule for exchange of weights and measures
1815
1815
1815
2000-100 BCE
1815
1893-4
1863-7
1775-1799 (original); 1900-1907 (model)
1990-96
1705-1737
1772 (original); 1919 (model)
4000-2001 BCE
1815
1870-10
1730; 1967
1836-02
1872-08
1816
1972-3
2500 BCE
1880-120
1816
1990-95
1818
1066; 1876
1945-50
1815
3000-1500
3000-2000 BCE
1817
2000 BCE
1817
1817
1818
1817
1818
1815
1817
1815
1816-1817
1815
1817
1817
1816
1816
1816
1816
1816
1816
1816
1816