
One long pear shaped vacuum tube with Maltese cross shaped anode
1879
1879
1907
1891
1905
1938-1948
1948-1950
1906
1925
1705
1855-1883
1948-1960
1955-1965
1891
1891
1936
1898
1891
1876
1898
1891
1891
1872
1907
1891
1898
1879
1891
1891