October 30, 1893-March 27, 1977

BY JOHN S. WAUGH

Don Yost who spent his entire professional career at the California Institute of Technology, was one of the leading American chemists of the period between the two world wars. He brought to inorganic chemistry the rigor of the physical chemist's approach, following the Berkeley school and the A. A. Noyes tradition in which he had been educated. He remained in the vanguard of new developments in chemistry and physics, pioneering the exploration and applications of Raman spectroscopy, the third law of thermodynamics, chemical applications of radioactive isotopes, fast reaction kinetics, and microwave spectroscopy and magnetic resonance. He was the author of influential monographs on inorganic chemistry and on the rare earth elements.

Yost was born on a strawberry farm near the small town of Tedrow, Ohio. After a succession of moves within the middle west, the family settled permanently on a ranch near Boise, Idaho, in 1902. There Yost finished elementary and high school. In that frontier environment no formal courses in chemistry, physics, or any other science were available. However, Yost and his boyhood friends formed a radio club and designed and built working radio stations. The receivers had diode detectors made from galena crystals found in the surrounding mountains. Yost's vector to-