Meyer, Julius Lothar
Julius Lothar Meyer (1830–1895) was virtually born into a scientific career. He came from a medical family of Oldenburg, Germany, and first pursued a medical degree. In medical school he became interested in chemistry, especially physiological topics like gases in the blood.
Meyer was among the young chemists attending the Karlsruhe Congress in 1860 where he was impressed with Stanislao Cannizzaro's presentation of Amedeo Avogadro's hypothesis. For Meyer, along with Dimitri Ivanovich Mendeleev, writing a textbook proved to be the impetus for developing the periodic table—that is, a device to present the more than 60 known elements in an intelligible fashion. For some time chemists had been trying to devise a logical system of classification by arranging the elements by atomic weight, but confusion over how to determine atomic weights thwarted their attempts. Soon after Karlsruhe, various new atomic arrangements were published, culminating in the work of Meyer and Mendeleev. In the first edition of Die modernen Theorien der Chemie (1864), Meyer used atomic weights to arrange 28 elements into 6 families that bore similar chemical and physical characteristics, leaving a blank for an as-yet-undiscovered element. His one conceptual advance over his immediate predecessors was seeing valence, the number that represents the combining power of an element (e.g. with atoms of hydrogen), as the link among members of each family of elements and as the pattern for the order in which the families were themselves organized. In his original scheme the valences of the succeeding families, beginning with the carbon group, were 4, 3, 2, 1, 1, and 2.
Meyer then published his classic paper of 1870 ("Die Natur der chemischen Elemente als Function ihrer Atomgewichte," Justus Liebigs Annalen der Chemie, supp. 7 ), 354–364), describing the evolution of his work since 1864. This paper is particularly famous for its graphic display of the periodicity of atomic volume plotted against atomic weight. Many chemists had their doubts about the periodic law at first, but these doubters were gradually converted by the discovery of elements predicted by the tabular arrangement and the correction of old atomic weights that the table cast in doubt. Meanwhile, Meyer and Mendeleev carried on a long drawn-out priority dispute.
Meyer continued to pursue a life of research and teaching and spent the last twenty years of his life as a professor at Tübingen.