
Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1851
1791
1808
1786
1776
1807
1787
1790
1796
1800
1794
1780
1767
1740-1760
1745
1830
1755
1710
1814
1795
1765-1775
1790
1700-1710
1792
1790
1785-1795
1730
1981-1990
1800
1788
1820
1823
1815
1700-1725
1840-1850
1804
1801-1900
1785
1775-1785
1700
1708-1710
1775
1795
1787
1899
1980
1814
1960-2000