Close-up view of the assembly of an apparatus used for sterile cultures of taller green plants at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen…

General view of the microapparatus and assorted laboratory equipment used to study bacterial nitrogen fixation at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.…

General view of an apparatus used to grow plants under sterile conditions 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 the hydraulic pump used to perform steel corrosion tests at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen Research Laboratory…

Close-up view of a lime glass tube, part of an apparatus used to investigate the thermionic emission from platinum films sputtered on glass at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

Close-up view of an apparatus used to study the absorption spectrum of ozone in visible and photographic infra red. This apparatus was used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

General view of an apparatus used to study the absorption spectrum of ozone in visible and photographic infra red. This apparatus was used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

M.C. Molstad demonstrating use of an apparatus for the removal of carbon dioxide from water gas by means of scrubbing under pressure at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in…

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 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 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…

Photograph of a double flask used by French biologist, microbiologist, and chemist Louis Pasteur (1822-1895) to demonstrate anaerobic fermentation, as displayed at the Pasteur Institute in Paris. Per notations…

Self contained pH meter with wooden exterior; hinged top door opens to reveal meter face and inlaid paper instructions for use; the dial is calibrated from pH 0 to pH 13 in .1 pH divisions; porcelain enamel lined…

Wooden box with handle at top and metal latch closure at front; interior: instructions for use printed on paper and inset into box lid; top face: window at center reveals pH scale "7-14" and millivolts "0-400"; control…

Self contained pH meter with wooden exterior; hinged top door opens to reveal meter face and inlaid paper instructions for use; the double scale reads pH and millivolts; hinged door on left side of wooden case opens to…

First marketed in 1960, the Beckman/Spinco Model 120 Amino Acid Analyzer used the Spackman-Stein-Moore technique of amino acid chromatography.

W.E. Kuentzel demonstrating use of an apparatus to remove carbon monoxide from water gas by means of scrubbing with a cuprous (i.e. copper) solution at the U.S. Department of Agriculture's Fixed Nitrogen Research…

General view of C.A. Black demonstrating use of an apparatus for filling tubes in order to study ammonia-carbon dioxide-Urea-water systems at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

General view of Dr. R.O.E. Davis demonstrating use of an apparatus for filling tubes in order to study ammonia-carbon dioxide-Urea-water systems at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory…

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 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 Cyanamide Laboratory at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory facilities located in Washington, D.C. Assorted glassware and laboratory apparatus, including a…

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 machinery used to crush ore at the Fixed Nitrogen Research Laboratory's blast furnace plant. A worker identified as "Parker" is seen transferring raw material, presumably ore, from a machine into a…

General view of Mrs. M.K. Murray demonstrating use of a nitrometer, an apparatus used to determine the amount of nitrogen or nitrogen compounds in a substance or mixture, at the U.S. Department of Agriculture's Fixed…