 Later, Lothar Meyer (1830–95) and Dmitrij Mendeleev (1834–1907) independently presented periodic tables covering all 63 elements known in 1869. In 1871, Mendeleev published his periodic table in the form it was subsequently acclaimed. This table was organized on the idea of periodically recurring general features as the elements are followed when sequentially ordered by relative atomic weight. The periodically recurring similarities of chemical behavior provided the basis of organizing elements into groups. He identified 8 such groups across 12 horizontal periods, which, given that he was working with just 63 elements, meant there were several holes.