John Newlands developed the Law of Octaves in 1866 which stated that elements had similar properties every eighth element, like the octaves in music. He arranged the 56 known elements in his octave table. The Law of Octaves worked well for lighter elements but failed for heavier ones discovered later. Dimitri Mendeleev later developed the periodic table, which became the accepted system for classifying elements by properties and arranged by atomic mass. The periodic table was later corrected by Henry Moseley in 1913.