Marine Timekeeper known as 'H5' by John Harrison and Son 1770
1770
1770
1960
1862
1913
1936
1775-1785
1785
1926
1705-1737
1783-1800
1900-1920
1802
1701-1800
1825
1862
1685
1799
1795-1810
1711
1941
circa 1840
1786
1791
1755
1775
1910-1936
1776
1796
1740-1760
1601-1700
1823
1700
1792
1790
1788
1897
1938
1700-1725
1784
1950-1980
1882-1889
1745
1600
1708-1710
1804
1780
1785-1795
1912
1800
1790