In 1916 the United States, almost entirely dependent upon foreign sources for its supply of commercial nitrogen, took the first step toward independence by appropriating $20,000,000 for the work of developing a domestic fixation industry. With this money the Corps of Engineers began, about the time we declared war against Germany, the construction of a great dam to arrest the power of the Tennessee River at Muscle Shoals, Alabama. This project, including a hydroelectric power house, was set for completion in 1923. The head of water at Muscle Shoals is expected to provide from 100,000 to 200,000 horsepower continuously, and during nine months of the year high water will produce a secondary power almost as great. Aware that this development would in all probability not come through in time to serve the war explosives program, soon after the declaration of war the Government entered upon an enormous project to fix atmospheric nitrogen with power developed from coal. Five fixation plants of this sort were from first to last authorized. Three of these were completely built, and the other two were partially constructed before their projects were canceled. In the fall of 1917 the War Department began the construction of a nitrogen plant at Sheffield, Alabama, and in 1918 completed it, at a cost of about $13,000,000. This plant produced usable nitrogen in the form of ammonium nitrate, a product used with trinitrotoluol in the production of the important shell-explosive amatol. It used the modified German Haber process, combining hydrogen and nitrogen to form ammonia, which is oxidized into nitric acid, which in turn is combined with ammonia to form ammonium nitrate. This plant produced its first ammonia in September, 1918, and its first ammonium nitrate on the second day of the armistice. The process, however, was never satisfactorily developed in this plant. The second fixation-plant project was inaugurated in the autumn of 1917 about the time the Interallied Ordnance Agreement put upon the United States the burden of producing most of the powder and explosives used by the Allies, thus tremendously increasing our need of nitrogen. It was no time to be experimenting with processes. The one fixation process of proved success known in the United States was the cyanamid process, used by the American Cyanamid Company at its plant at Niagara Falls. The Government therefore engaged this concern to build an enormous fixation plant at Muscle Shoals, a plant which was to use steam power until the hydroelectric power from the river should become available. On the day of the armistice this plant, known as the No. 2 Nitrate Plant, was nearly complete: it turned out its first ammonium nitrate within two weeks thereafter. It cost $70,000,000 and had a capacity of 110,000 tons of ammonium nitrate a year. The test runs indicated that the plant could fix nitrogen at a cost commercially practicable.