Two views of device used to study positive ions, presumably in the activation of nitrogen gas and hydrogen, at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. The activation of nitrogen gas and hydrogen is part of the synthesis of ammonia. The individual seen holding the device in the second photograph is identified as Dr. C.H. Kunsman.

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.