Julius Lothar von Meyer (August 19, 1830 - April 11, 1895) was a German chemist. He is best known for the share he had in the periodic classification of the elements. His book on Die modernen Theorien der Chemie, published in 1864, has an early version of the periodic table containing 28 elements classified into 6 families by their valence. Mendeleev published his periodic table of all known elements in 1869. Working completely independently, a few months later, Meyer published a revised and expanded version of his 1864 table, virtually identical to that published by Mendeleev.