TY - MANSCPT DB - Science History Institute DP - Science History Institute M2 - Courtesy of Science History Institute. Rights: No Known Copyright TI - Investigation of thermionic emission of positive ions ID - 7s75dc52b DA - 1930/01/08/ YR - 1930 AV - Travis P. Hignett Collection of Fixed Nitrogen Research Laboratory Photographs, Box 2 VL - Travis P. Hignett Collection of Fixed Nitrogen Research Laboratory Photographs, Box 2 AN - Travis P. Hignett Collection of Fixed Nitrogen Research Laboratory Photographs, Box 2 UR - https://digital.sciencehistory.org/works/7s75dc52b AB - General view of an apparatus used to investigate the thermionic emission of positive ions from platinum films sputtered on glass at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. In chemistry, the term "thermionic" is commonly used to describe a substance or value related to or operated by electrons emitted from materials at high temperatures. The individual present in the photograph is identified as Mr. Nelson. The Fixed Nitrogen Research Laboratory (F.N.R.L.) was established at American University in 1919 under the directorship of Arthur B. Lamb. Initially part of the War Department, the F.N.R.L. was the successor to several wartime initiatives to develop a secure domestic supply of nitrate compounds necessary for the manufacture of explosives during World War I. With a staff of about 110 individuals, including 35 to 50 chemists, the F.N.R.L. focused on the manufacture, production, and development of products of atmospheric nitrogen, including munitions and fertilizers. KW - Nitrogen fertilizer industry KW - Nitrogen--Fixation KW - United States. Bureau of Chemistry and Soils KW - United States. Department of Agriculture KW - Employees KW - Laboratories KW - Scientific apparatus and instruments LA - ER -