Mendeleev had not set out to reorganise the fundamental structure of chemistry ... Mendeleev’s substantive claim was not merely that these positions were empty ... It was not discovered within Mendeleev’s lifetime.
In March 1869, DmitriMendeleev presented to the RussianChemical Society a way of laying out around sixty elements then known ... What Mendeleev did with the repetition was different in degree ... Mendeleev ...