![](https://coimages.sciencemuseumgroup.org.uk/333/916/large_thumbnail_smg00047180.jpg)
Coin checking equal-arm balance
1653
1653
1700-1710
1779
1750-1760
1800-1810
1700-1799
1680-1699
1810
1790
1820
1800-1899
1626
1763-1779
1775
1735-1779
1780-1782
1763-1779
1700-1725
1800-1810
1774
1800-1812
1770
1770-1780
1763
1768-1782
1600-1630
1611
1800-1805
1780-1799
1620-1640
1800-1810
1693-1702
1750
1693-1731
1763-1781
1727-1745
1841-1865
1768-1777
1783-1797
1600-1644
1650-1655
1770
1800-1899
1817