Leason Heberling Adams (January 16, 1887 – August 20, 1969) was an American geophysicist and researcher. His principal achievement was his research on the properties of materials exposed to very high pressures, which he used to derive information on the nature of the Earth's interior. He received the William Bowie Medal of the American Geophysical Union in 1950 for his work. Biography Born on 16 January 1887, Adams grew up in central Illinois, where he received his early education in a one-room school. At the age of fifteen he entered the University of Illinois at Urbana–Champaign, graduating in 1906 with a Bachelor of Science degree in chemical engineering. After completing his university studies, he worked for the Technology Branch of the United States Geological Survey, first as an industrial chemist and then as a physical chemist. In 1910 he began working at the Geophysical Laboratory of the Carnegie Institution for Science in Washington, D.C. In 1937 he became the director of the Laboratory, and during World War II he served as the director of Division I (ballistics) of the Office of Scientific Research and Development. He was elected to the United States National Academy of Sciences in 1943. Adams retired from the Carnegie Institution in 1952 but continued to carry out research, first as a consultant to the director of the National Bureau of Standards and then from 1958 until 1965 as a professor of geophysics at the University of California, Los Angeles. He died on 20 August 1969 in Silver Spring, Maryland. Research Adams performed one of his first research projects during World War I, when he produced optical glass. He helped to develop a new method for annealing glass which was effective for large blocks, and then used this technique to make a 200-inch mirror for the Hale telescope at the Mount Palomar Observatory. For this work, he received the Edward Longstreth Medal of the Franklin Institute. Geophysical work His most enduring work began in 1919, when he was working at the Carnegie Institution for Science to develop new methods for high-pressure measurement. In the late 19th century the prevailing view of the Earth was that it was made up of a thin crust floating on a molten interior. By Adams' day, this view was being challenged, especially by the findings of some seismologists who had found the wave velocities of the Earth at different depths. Wave velocities