Day, Arthur L.

Day, Arthur L. (Louis) (1869–1960) geophysicist; born in Brookfield, Mass. While serving on the U.S. Geological Survey (1900–07), he investigated melting temperatures of igneous rocks, and developed the measurement of temperatures above 1150° Celsius. He directed the Carnegie Institution's Geophysical Laboratory (1906–36), where his research included temperature and gas measurements of volcanoes and hot springs, seismological studies, and radioactivity disintegration determinations of the age of ocean core samples. He contributed to the Corning Glass Works' large-scale manufacturing techniques for producing optical glass.