Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1780-1850
1870
1962
1999
1680-1690
1799
1786
1755
1630-85
1791
1700-1815
1700-1725
1625
1680-1685
1640
1790
1830
1823
1700-1725
1700-1725
1801-1819
1814
1928
1675
1660
1708-1710
1800
1680
1690
1660
1650
1630
1680
1702
1640-1660
1680
1622-1628
1700
1755
1730
1790
1660
1690-1695
1807
circa 1801
1630
1650
1849
1700-1725