Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1775-1785
1785
1851
1840-1850
1795
1981-1990
1786
1755
1791
1796
1776
1808
1710
1700
1740-1760
1790
1830
1823
1788
1899
1814
1780
1745
1804
1787
1708-1710
1792
1795
1801-1900
1787
1800
1815
1800
1765-1775
1730
1790
1700-1725
1820
1700-1710
1775
1807
1785-1795
1794
1767
1790
1980
1501-1600
1814
1873