
Midget circular slide rule by Dietzgen
1955
1955
1948-1952
1948-1952
1947
1900-1920
1944
1880-1890
1870-1875
1818-1820
1962
1955
1965-70
1942
1878-1882
1660-1680
1837-1848
1918-1921
circa 1900
circa 1940
1880-1890
1846-1880
1920-1940
1904-1907
1959-1960