Julius Lothar Meyer (August 19, 1830 - April 11, 1895) was born in Varel, at that time belonging to the duchy of Oldenburg, now part of Germany. He was contemporary and competitor of Dmitri Mendeleev to draw up the first periodic table of chemical elements. Some five years apart, both Mendeleev and Meyer worked with Robert Bunsen. Meyer qualified in medicine at Zürich, Switzerland, and then studied and taught at various German universities. His first interest was the physiology of respiration, and in 1857, he recognized that oxygen combines with the haemoglobin in blood. In 1864, Meyer published an early version of the periodic table, containing 28 elements classified into 6 families by their valence-the first time that elements had been grouped and ordered according to their valence. Work on organizing the elements by atomic weight had hitherto been stymied by inaccurate measurements of the atomic weights. Mendeleev published his periodic table of all known elements (and predicted several new elements to complete the table, plus some corrected atomic weights) 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, and a paper showing graphically the periodicity of the elements as a function of atomic weight. Many chemists were doubtful about Mendeleev's periodic law, but Meyer's work provided significant support, particularly when the new elements were found as predicted and remeasured atomic weights accorded with those predicted. Meyer's contributions also included the concept that the carbon atoms in benzene were arranged in a ring, although he did not propose the alternation of single and double bonds that later became included in the structure by Kekulé.