Welsbach, Baron Carl Auer von (1858-1929), an Austrian chemist. During the 1880's in the laboratory of Robert Wilhelm Bunsen, inventor of the Bunsen burner, he did research on rare-earth elements and their compounds. Von Welsbach noted that some of the compounds burned brilliantly, and he began to use them in gaslight appliances he invented, including the gas mantle. He discovered neodymium and praseodymium (1885), two of the rare-earth elements. In 1907, von Welsbach and G. Urbain (working independently) discovered lutetium and isolated ytterbium, two more rare-earth elements.