SPUTNIK / SCIENCE PHOTO LIBRARY SPUTNIK / SCIENCE PHOTO LIBRARY
Dmitry Mendeleyev and Bohuslav Brauner. Mendeleyev (left, 1834-1907) was a Russian chemist, while Brauner (1855-1935) was a Czech chemist. Mendeleyev is famous for his work on organising trends in atomic weights and valency. From this work, he developed the first true periodic table of the elements (final version published in 1871). This contained some gaps, but new elements were later discovered to have the properties predicted by the table. Brauner worked on the same problems, and in 1902 he extended the periodic table downwards beyond lanthanum, predicting the existence of a new element between neodymium and samarium. Photographed in Prague, Czechoslovakia, on 1 April 1900.
Model release not available. Property release not required.