Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1610; 1923
1769
1763
1990-96
1772 (original); 1919 (model)
1705-1737
1761-1762
c.1750
1750-1774
1752
1750
1755
2000-100 BCE
4000-2001 BCE
1750-1770
1762
1771
1750-1766
1769
1770
1755
1755
1762
1762
1761
1750
1752
1771
1750-1760
1750-1760
before 1753
1761
1765
1761
1752
1762
1761
1762
1755
1762
1750
1752
1750
1760
1752
1770
1762
1762
1755