Two views of an exhibition display concerning the work of the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. The display includes assorted sample jars and a photograph viewer, as well as an apparatus used to prepare potassium nitrate from potassium chloride and nitrogen peroxide. These photographs were taken in the Agricultural Hall at the Sesqui-centennial International Exposition held in Philadelphia in 1926.

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.