General view of an apparatus used to measure the effect of radiation on chemical reactions at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen…

General view of an apparatus used to study the relative activity of potassium ions and electrons in the synthesis of ammonia from nitrogen and hydrogen gas at the U.S. Department of Agriculture's Fixed Nitrogen Research…

General view of the construction and calibration of an apparatus used to analyze the decomposition of ammonia on hot surfaces at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in…

General view of the gas purification rack, a component of an apparatus used to study the catalytic decomposition of ozone at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington,…

General view of an apparatus used to study the catalytic decomposition of ozone at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen Research…

General view of the Bone and Wheeler gas analysis apparatus used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. A Bone and Wheeler apparatus, which reads gas…

General view of an apparatus used to investigate the Phase Rule in an iron-nitrogen system at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. First proposed by Josiah…

General view of Dr. D.C. Bardwell using an apparatus to experiment with the chemical effects of radon at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed…

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…

General view of an apparatus used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory to determine the solubility of gases in water at various temperatures and pressures up to 1,000 atmospheres.
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General view of an apparatus used to analyze micro quantities of gases at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen Research Laboratory…

General view of an apparatus for the study of equilibrium in the iron-water-iron oxide-hydrogen system at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed…

General view of the organic combustion furnace and train utilized 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.)…

General view of an apparatus used to measure vapor pressures in the study of Urea synthesis at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. In the production of…

General view of Dr. Leatherman using an apparatus to measure traces of inert gas and air in nitrogen at the Fixed Nitrogen Research Laboratory's High-Pressure Laboratory.

The Fixed Nitrogen Research Laboratory…

General view of Dr. Leatherman using an apparatus to determine the amount of inert gas present in nitrogen made from the fractionation of liquid air at the Fixed Nitrogen Research Laboratory's High-Pressure Laboratory. …

General view of compressor used in the carbon dioxide refrigeration system at the Fixed Nitrogen Research Laboratory's High-Pressure Laboratory. The individual present in the photograph is identified as Mr. Tremearne.
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General view of an apparatus used to analyze hydrogen at the Fixed Nitrogen Research Laboratory's Synthetic Ammonia Division.

The Fixed Nitrogen Research Laboratory (F.N.R.L.) was established at American University in…

General view of assorted apparatus used in the Fixed Nitrogen Research Laboratory's High-Pressure Laboratory, including a hydraulic pressure pump, piston-type gauges, high-pressure booth, and valve manifold. The…

General view of the thermostat and other equipment used to measure gas volumes in order to make compressibility determinations at the High-Pressure Laboratory, part of the U.S. Department of Agriculture's Fixed…

General view of the thermostat and assorted apparatus used to study the compressibility of gases at high pressures at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. …

General view of a thermostat and equipment used to determine the compressibility of gas at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. In chemistry,…

Mr. Hetherington demonstrating the barometers and potentiometer used for temperature control at the High-Pressure Laboratory, part of the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facilities…

General view of the apparatus used to measure gas volumes in order to make compressibility determinations at the High-Pressure Laboratory, part of the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

General view of an apparatus used to study the thermal decomposition of ammonia of the surface of tungsten, molybdenum, nickel, and iron catalysts at the U.S. Department of Agriculture's Fixed Nitrogen Research…