Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1610; 1923
1769
1763
1990-96
1761-1762
1705-1737
1755
1755
2000-100 BCE
1762
1755
1769
4000-2001 BCE
1770
1755
1762
1755
1762
1761
1762
1765
1761
1762
1761
1762
1761
1755
1762
1770
1760-1770
1761
1762
1755
1760
1762
1760
1762
1761
1764
1762
1766
1758-1769
1761
1762
1762
1761
1761
1758-1769
1758-1769