View of a shaking machine designed at the Arlington Experimental Farm in Arlington, Virginia. Established by an act of Congress in April 1900, Arlington Farm served as the main field laboratory for the Bureau of Soils,…

Four stoppered jars containing samples of commercial fertilizer and concentrated fertilizer mixtures produced at the Arlington Experimental Farm in Arlington, Virginia. Established by an act of Congress in April 1900,…

General view of the repair shop at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory showing assorted machinery and apparatus.

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

General view of reaction bombs used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory to test catalysts at 100 atmospheres of pressure. Numbers are visible on the exterior of the various…

General view of Mr. Merz using an apparatus to determine the hygroscopicity of fertilizer materials and mixtures at the the Arlington Experimental Farm in Arlington, Virginia. Established by an act of Congress in April…

General view of a table-top model of a synthetic ammonia plant showing an assortment of plant machinery and apparatus. The model was created by the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

General view of a metallic contact apparatus, likely used to measure electrical contact between metallic objects, at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.
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General view of the machine shop at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facilities located in Washington, D.C.

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

General view of the library 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…

General view of a laboratory at the Fixed Nitrogen Research Laboratory's catalyst testing plant. Various laboratory glassware and scientific apparatus are visible in the photograph, as well as a supply cabinet…

General view of acetylene welding at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. The man visible in the photograph is identified as J.J. Connor. This photograph is…

General view of high-pressure purification apparatus used at the Fixed Nitrogen Research Laboratory's catalyst testing plant.

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

General view of a high-pressure pump 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…

General view of a high-pressure pump 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…

General view of a high-pressure circulating pump 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…

General view of a high-frequency apparatus used in the Fixed Nitrogen Research Laboratory's Arc Laboratory. In the early 20th century, the arc process, in which electric generators are used to combine nitrogen and…

General view of the general repair shop at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facilities located in Washington, D.C.

The Fixed Nitrogen Research Laboratory (F.N.R.L.) was…

General view of the exterior of the gas storage facility at the Fixed Nitrogen Research Laboratory's catalyst testing plant. Two unidentified workers are visible on the right-hand side of the photograph. A sign reading…

Group photograph of unidentified personnel from 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…

General view of F.F. Robey at work in the carpenter shop at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory showing assorted machinery and apparatus.

The Fixed Nitrogen Research Laboratory…

General view of the electrical shop at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory showing assorted machinery and apparatus. The man visible on the left-hand side of the photograph is…

General view of the electron inertia apparatus 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…

General view of electrolytic cells used for the production of hydrogen 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 E.J. Fox and K.S. Love at work in the Nitrogen Analytical Laboratory at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facilities located in Washington, D.C. Assorted glassware…

General view of Dick Adams using an apparatus to determine the hygroscopicity of fertilizer materials and mixtures at the the Arlington Experimental Farm in Arlington, Virginia. Established by an act of Congress in…