
Telegraph block instrument; Walker's
1865
1865
1899
1901
1901
1896
circa 1920
1897
1897
circa 1880
1915
1905
1903
1890
1870
1913
1901
1895
1907
1878
1934
1875-1877
1903
1872
1901
1915
1874
1880
1893
1907
1862-1863
1865
1902
1882-1890
1839 (original); circa 1988 (replica)
1916
1864
before 1889
1705-1737
1860-1900
1879
1922
1880-1890
1905
1878
1889
1922
1888
1880-1900
1917
1880