
Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1744-1774
circa 1750
1752
1762
1755
1735-1752
1745-1755
1745-1755
1735-1754.
1755
1745-1755
1752
1770
1750-1760
1720
1755
1729-1753
1735-1753
1762
1762
1769
1757
1752
1761
1762
1762
1761
1762
1762
1762
1762
1762
1740-1760
1767
1715-1725
1745
1760
1715-1725
1755
1739
1740-1749
1750-1760
circa 1715
1745-1755
1750
1730
2000-100 BCE
1725-1755
c.1750