Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1610; 1923
1769
1990-96
1763
1772 (original); 1919 (model)
1705-1737
1761-1762
1752
1755
2000-100 BCE
4000-2001 BCE
1771
1762
1755
1769
1770
1755
1755
1762
1762
1761
1752
1762
1752
1771
before 1753
1761
1765
1752
1761
1762
1761
1762
1762
1755
1752
1760
1752
1762
1770
1752
1755
1762
1772-1773
1760
1760-1770
1761
1761
1764