
Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1748-1763
1764
1750-1766
circa 1750
1745-1755
1752
1762
1750
1752
1770
1755
1750-1760
1755
1735-1752
1735-1753
1762
1762
1769
1745-1755
1745-1755
1735-1754.
1757
1758-1769
1758-1769
1760-1770
1758-1769
1742
1740-1753
1752
1761
1762
1762
1761
1762
1762
1762
1762
1762
1767
1740-1760
1745
1760
1755
1739
1740-1749
1750-1760
1767
1750
2000-100 BCE