Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1610; 1923
1769
1735-1745
1763
1990-96
1705-1737
1761-1762
c.1750
1730-1750
1752
1750
1755
1745-1755
2000-100 BCE
4000-2001 BCE
1750-1770
1762
1750-1766
1769
1770
1745
1755
1745-1755
1755
1762
1762
1730-1770
1730
1740-1760
1740-1749
1761
1750
1752
1750-1760
1750-1760
before 1753
1761
1765
1745
1761
1752
1762
1735-60
1761
1762
1745-1755
1755
1742
1762