Photograph of James Wilson, Secretary of Agriculture from 1897 to 1913, seated in a horse-drawn carriage with an unidentified African American driver. Wilson's tenure as Secretary is regarded as a period distinguished…

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 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…

Two views of apparatus and equipment used to produce an intermediate suitable for conversion to potassium metaphosphate at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington,…

General view of the exterior of the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facility located at American University near Washington, D.C. The Fixed Nitrogen Research Laboratory (F.N.R.L.) was…

Two views of the No. 2 experimental blast furnace on a burden (a load, especially a heavy one) of phosphate at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant.

The Fixed Nitrogen Research…

Assorted views of the Fixed Nitrogen Research Laboratory's experimental blast furnace plant during a Tennessee Valley Authority (T.V.A.) operation.

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

General view of unidentified employees observing the temperature inside the Royster stoves at the Fixed Nitrogen Research Laboratory's experimental blast furnace plant during a Tennessee Valley Authority (T.V.A.)…

Group photograph of personnel at the Fixed Nitrogen Research Laboratory's experimental blast furnace plant, taken at the conclusion of a Tennessee Valley Authority (T.V.A.) operation. Per notations accompanying the…

General view of a worker emptying the slag ladle on the No. 2 experimental blast furnace on a burden (a load, especially a heavy one) of phosphate at the U.S. Department of Agriculture's Fixed Nitrogen Research…

Four views of the hearth and crucible of the No. 2 experimental blast furnace at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. The photographs show the hearth and…

General view of the flushing of the No. 2 experimental blast furnace 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 workers opening the cinder-notch on the No. 2 experimental blast furnace on a burden (a load, especially a heavy one) of phosphate at the U.S. Department of Agriculture's Fixed Nitrogen Research…

General view of the No. 2 experimental blast furnace on a burden (a load, especially a heavy one) of phosphate at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant.

The Fixed Nitrogen Research…

General view of the carbon tube precipitator and spray tower for the experimental blast furnace at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen…

Two views of the interior of the Engine Room at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory, with both full and partial views of the blowing engines for the experimental blast furnace.

The…

Two views of the Royster stoves used for the No. 2 experimental blast furnace at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. According to notations accompanying…

General view of the superstructure of the No. 2 experimental blast furnace, as seen from the platform of the No. 1 precipitator at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant.

The Fixed…

Two views of the No. 2 experimental blast furnace at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant. The individuals visible in the first photograph are identified (left to right) as Reilly;…

Two views of the No. 2 furnace and stock piles at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant. The stock piles likely contained a mix of raw material, including greensand, leucite, coke,…

General view of Travis P. Hignett examining blowing engines for the experimental blast furnace at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen…

Three views of Mr. Royster (left) and Travis Hignett (right) tapping slag from the experimental blast furnace at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C. Mr.…

General view of culture samples used for an experiment to determine if corn growing under sterile conditions can use ammonia nitrogen. This experiment was conducted at the U.S. Department of Agriculture's Fixed Nitrogen…

General view of an apparatus used to study the structure of molecules by means of the Raman effect using a three-glass prism Steinheil Spectrograph. This apparatus was used at the U.S. Department of Agriculture's Fixed…

Two views of the liquid ammonia and carbon dioxide pumps and coolers at the Fixed Nitrogen Research Laboratory's Urea Plant. In the production of fertilizer, liquid carbon dioxide and liquid ammonia are commonly…