Welding welding was invented in 1893, and around that time another process, oxyfuel welding, became well established. Acetylene was discovered in 1836 by Edmund Davy, but its use was not practical in welding until about 1900, when a suitable torch was developed. At first, oxyfuel welding was one of the more popular welding methods due to its portability and relatively low cost. As the 20th century progressed, however, it fell out of favor for industrial applications. It was largely replaced with arc welding, as advances in metal coverings (known as flux) were made. Flux covering the electrode primarily shields the base
Kirk Johnson (scientist) a master's degree in geology and paleobotany. He received his PhD in geology and paleobotany from Yale University in 1989. While in graduate school, in 1987, he discovered an extinct species of linden leaf, which was named Tilia johnsoni in his honor. His postdoctoral work included field research in the northern Australian rainforests, while he served as a postdoctoral research associate in the department of botany at the University of Adelaide. From 1991 to 2012, Johnson worked at the Denver Museum of Nature and Science, first as a lead scientist, then the chief curator and vice president of research and