William Weber Coblentz (November 20, 1873 – September 15, 1962) was an American physicist notable for his contributions to infrared radiometry and spectroscopy. Early life, education, and employment William Coblentz was born in North Lima, Ohio to parents of German and Swiss descent. His mother (Catherine) died when Coblentz was just under three, leaving him temporarily with a family of just his younger brother (Oscar) and their father (David). However, the father remarried about 2 years later, and Coblentz appears to have admired his second mother (Amelia). Throughout Coblentz's childhood and adolescence, his family lived on farms, but apparently were never able to buy one of their own. The family's extremely modest circumstances led to a somewhat-delayed education for Coblentz, who did not finish high school (Youngstown, Ohio) until 1896, when he was 22 years old. Coblentz entered the Case School of Applied Science, now Case Western Reserve University in the fall of 1896, and received his Bachelor of Science degree in physics in June, 1900. He went on to earn MS (1901) and PhD (1903) degrees from Cornell University in Ithaca, New York, staying two years beyond his doctoral time by working as a Research Fellow with support from the Carnegie Institution. In the spring of 1905, Coblentz accepted a position with the newly founded National Bureau of Standards (now the National Institute of Standards and Technology, NIST) in Washington, DC, where he spent his entire career. In 1905 he founded the Bureau's radiometry section, and headed it for 40 years until his retirement in 1945. Scientific work During the course of a long and productive career, Coblentz made many scientific contributions both of a pure and applied nature. Bibliographies of his work show that he had hundreds of scientific publications, talks, and abstracts to his credit. He received a total of ten patents during his lifetime, the first being US Patent 1,077,219 for a solar cell invention to convert sunlight to electricity. Coblentz's first publication, "Some Optical Properties of Iodine", was based on his PhD research. On acquiring his doctorate, he soon began publishing regularly on problems related to infrared (IR) radiation, both those concerning spectroscopy and those concerning radiometry. For example, Coblentz was among the first, if not the very first, to verify Planck's Law. Infrared studies When Coblentz entered Cornell University, infrared spectroscopy was in what today would be considered an extremely primitive state. As a