General view of the apparatus used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory to introduce silica gel into an arc process. In the early 20th century, the arc process, in which electric generators are used to combine nitrogen and oxygen in the high temperatures of an electric arc, was one of several processes used to "fix" or chemically combine nitrogen with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites.

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.