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