TY - MANSCPT DB - Science History Institute DP - Science History Institute M2 - Courtesy of Science History Institute. Rights: No Known Copyright TI - Ultrasonic oscillator with soil suspension ID - 0p0967046 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/0p0967046 AB - Close-up view of an ultrasonic oscillator with a soil suspension and view of the driving transformer and oil bath containing piezoelectric quartz crystal. This oscillator was used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. 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 - Oscillators, Crystal KW - United States. Department of Agriculture KW - Piezoelectricity KW - Scientific apparatus and instruments LA - ER -