Germany's predetermined war plans. This menace to the shipment of Chilean nitrate of soda was removed as soon as Great Britain could get a large naval force to South American waters. Since nitrate of soda represents some three-fourths of the total exports of Chile and the Government derives over 50 per cent of its revenue from the export duty on nitrate, the temporary cutting off of the foreign market for this product represented a veritable calamity for Chile. The revenue derived from saltpeter decreased from $32,446,303 in 1913 to $23,369,471 in 1914, and it must be remembered that war was not declared until August of 1914.

The production decreased from a normal output of over 250,000 tons per month to a minimum in February, 1915, of 89,904 tons. The oficinas in operation decreased from 134 in July, 1914, to a minimum of 36 in March, 1915. Beginning with March, 1915, the production gradually increased until October, when the monthly production approximated the normal prewar output. At this time the number of oficinas in operation, however, was somewhat less than before the outbreak of the war, probably due to the cessation of operations of the German controlled companies. Aside from the sinking of the German fleet by the British navy the industry was stimulated by the Chilean Government, who encouraged the producers to continue operations by advancing 3 pesos for each quintal of nitrate mined and 4 pesos for each quintal ready for shipment.

The decline in exports of Chilean nitrate in the later part of 1914 from the normal prewar exports is shown by the following table:

Although nitrate prices in countries foreign to Chile have risen markedly owing to war conditions, the price in Chile, owing to surplus stocks awaiting shipment, has not responded to the same degree as shown by the table of prices on page 86. At the present time (1918) virtually all of the selling of Chilean nitrate is to the British and United States Governments under a well-defined system; and the price quotation for some months past has been about $2.67 per 100 pounds in Chile. The United States is taking about two-thirds of the output of the Chilean mines.

1 For 1913-1916, inclusive, from Association Salitrera de Propaganda; 1917-1919, from publications of International Institute of Agriculture, Rome, Italy. 2 From Caliche, Organo del Instituto Cientifico E Industrial del salitre, Santiago, Chile, August, 1919. 3 First three months.

Tariff consideration.-Tariff questions on nitrate of soda involve the recent developments of synthetic nitric acid and ammonia in this country. Until the entrance of the United States into the war entire dependence was placed on Chile for supplies of nitrate of soda needed for military explosives, chemicals, and fertilizers. The entry of the United States into the war radically changed the situation. The demands for explosives were enormously increased, and the alarming success of the German submarines during 1917 made dependence on Chile for nitrates increasingly dangerous. The possibility had to be faced that the German submarines would secure virtual command of the sea.

It was, therefore, sound public policy to take steps to insure an adequate supply of nitrates from sources beyond the reach of the submarine. The nitrate program of the War Department was enormously increased. On October 15, 1917, the erection of nitrate plant No. 1 was begun near Sheffield, Ala. This plant was planned to have a capacity of about 10,000 tons of ammonia to be made by the direct combination of nitrogen and hydrogen in accordance with plans prepared by the General Chemical Co. This process had not been previously operated on a large manufacturing scale and the War Department decided not to place entire reliance upon it. Certainty of production at an early date became the paramount .consideration, and comparative cost and probable competitive strength after the war were of minor importance.

The cyanamid process was in successful large-scale operation at Niagara Falls, Canada, and the technical knowledge of the staff of this plant was available to the Government of the United States. A cyanamid plant could consequently be erected with assurance that when completed it would function properly without long delays to correct mistakes in design almost inevitable when the design is based solely on small-scale experiments.

Although no large-scale plant for the conversion of ammonia into nitric acid was in operation in the United States, much experimental work on the process had been carried out by the American Cyanamid Co., and by the Bureau of Mines in cooperation with the SemetSolvay Co. These experiments had been sufficiently successful to justify reliance on this method in connection with the Haber and cyanamid processes in preference to the arc process, which was excluded on account of its enormous power requirements. Accordingly nitrate plant No. 2 was started near the Muscle Shoals on the Tennessee River near Sheffield, Ala. It was designed to produce. 220,000 tons of calcium cyanamid, equivalent to 50,000 tons of ammonia annually. It is expected ultimately to use water power from Muscle Shoals, but since at least three years will be required to build the dams and power houses a steam-power plant was erected to furnish the power needed at once.

Before the construction of plant No. 2 had proceeded very far, the program was again increased and orders given for the construction of plant No. 3 near Toledo and plant No. 4 near Cincinnati, which were similar to No. 2 in design.

At the date of the signing of the armistice, plants Nos. 1 and 2 were in operation in part, although all the units were not yet completed. Plants Nos. 3 and 4 had advanced only a little beyond the preliminary work of clearing the land and laying foundations. Further work on No. 3 and No. 4 was stopped, and these plants have been abandoned.

Plant No. 1, which was to produce synthetic ammonia, however, was not completely successful. Mistakes were made in the design, so that the completed plant did not operate in an entirely satisfactory way. This is not surprising since the designs were based on experiments on a much smaller size, and no one in America had any experience in the operation of a large size commercial plant. Ordinary business prudence, which requires that every detail of design should be perfected through construction, operation, and modification of a single large size unit before the construction of a large plant of many units, was deliberately neglected in this case on account of the urgent necessity for speed. Much of the construction is of good usable quality, including railroad connections, the village for workmen, power plant, repair shops, offices, factory buildings, and a large part of the special manufacturing equipment. Some of the special equipment for the process will have to be redesigned and rebuilt. The titles to the patents on the Haber process have been seized by the Alien Property Custodian, and, therefore, the need of avoiding infringement will no longer hamper the reconstruction of the plant. There can be little doubt that it can be put in good working condition by the expenditure of a small fraction of the original cost. The cyanamid plant (Nitrate Plant No. 2) is of good design and in good working order, the design having been prepared by engineers experienced in the operation of a successful large plant.

The final disposition of these plants which are owned by the Government has not been decided at the present time (January, 1921).

There are three possible methods of disposition: First, Government ownership and operation of the plants directly or indirectly through a corporation controlled by the Government; second, the sale of the plants to private firms with the idea that they would operate them for the production of fertilizer materials if a purchaser can be found; third, the Government to retain the ownership and not operate the plants, holding them in reserve for military emergency.

SODIUM NITRITE.

Description and uses.-Sodium nitrite is a chemical compound of the formula (NaNO,). It forms small crystals which possess a faint yellow color; the pure dry salt is colorless. The salt dissolves readily in water. The commercial product contains between 96 and 98 per cent of sodium nitrite.

Sodium nitrite is used chiefly in the manufacture of azo dyes and in the dyeing of textiles, where it is used to develop the color on the fiber. It also has minor laboratory and pharmaceutical uses.

Occurrence and preparation. Sodium nitrite occurs native in small amounts in Chile saltpeter. It has been usually prepared, however, by the reduction of sodium nitrate (Chile saltpeter). The reducing agents are usually lead, iron filings, or graphite.

On a large scale sodium nitrite is made by reducing sodium nitrate by means of lead. The lead used should be as free as possible from zinc and antimony. The nitrate of soda is first melted in a castiron vessel; the required amount of lead is then added, keeping the liquid in constant agitation. The product from this fusion contains over 90 per cent sodium nitrite and some caustic soda and unreduced nitrate of soda. This mass is extracted with water, the alkaline liquid is neutralized with nitric acid, and allowed to settle. The clear liquid is now evaporated and run into lead-lined wooden tanks to crystallize. The mother liquors from the first batch of crystals can be evaporated several successive times with a yield of crystals each time. The crystals obtained, however, decrease in purity with the increase in number of evaporations. If an especially pure product is desired the salt is recrystallized.

Sodium nitrite is also produced from atmospheric nitrogen and by the oxidation of ammonia, which may be produced from byproduct coke ovens or synthetically from atmospheric nitrogen. În the oxidation of nitrogen by the arc process equal volumes of nitrous and nitric oxide can be produced under certain conditions. This mixture when absorbed in a solution of soda ash forms sodium nitrite. The same proportion of nitrous and nitric oxides can be obtained in the ammonia oxidation process and can be absorbed to form sodium nitrite. The arc process method is used in Norway, and by the American Nitrogen Products Co., Seattle, Wash., while the ammonia oxidation method is being used by the Solvay Process Co., at Syracuse, N. Y.

Imports.-The imports of sodium nitrite have increased from 1,696,567 pounds in 1915 to 3,675,179 pounds in 1917. This increase can be accounted for by the establishment of a dye industry in the United States.

POTASSIUM NITRATE.

Description and uses.-Potassium nitrate or saltpeter is a chemical compound containing potassium, nitrogen, and oxygen. It has the chemical formula KNO,. It is very similar to sodium nitrate in its chemical properties. When pure it is a white crystalline powder, or transparent colorless prisms. It is readily soluble in water and has a cooling saline taste. There are two grades of nitrate of potash, a crude product used principally for fertilizer purposes and a refined grade used for chemical purposes. The crude is admitted free of duty while the refined is dutiable at $7 per ton.

The chief use of nitrate of potash is in the manufacture of explosives and fertilizers. The Census of Manufactures for 1914 shows that the explosives industry consumed about 2,700 short tons of nitrate of potash, which was a decrease from the consumption in 1909 of about 3,500 short tons. The same source shows that in 1914 that the fertilizer industry consumed 507 short tons of nitrate of potash valued at $28,287. Potassium nitrate is also used in the manufacture of matches, in pyrotechnics, in assaying, in metallurgical operations, for analytical purposes, and for curing meat. It has a minor use for pharmaceutical purposes.

Occurrence and preparation.-Potassium nitrate or saltpeter is obtained, chiefly, from natural deposits in British India and from nitrate of soda by treatment with potassium chloride.

In many tropical countries, especially in India, Persia, and Egypt native deposits of potassium nitrate are found impregnating the earth in the neighborhood of large cities. The most important deposits are in the district of Tirhut, Bengal. The deposits are constantly forming, a white crust appears on the surface and is scraped up, lixiviated with water, and the clear solution evaporated to obtain the nitrate of potash.

In addition to these Indian earths the Chilean nitrate-bearing earths or "caliche" contain nitrate of potash varying from 1 to as high as 18 per cent in some deposits. The E. I. Du Pont Co. has developed a method for separating the nitrate of potash from the nitrate of soda in working the Chilean caliche. This process is now supplying considerable nitrate of potash to this country and should continue to develop, as it is worked in conjunction with the production of nitrate of soda.

There is also some potassium nitrate-bearing earths in Mexico and Central America. These deposits are very similar to those in India. Offerings from this source have been made to the American manufacturers of fertilizers but the price has been too high to compete with Indian nitrate from British India which is now being secured by a cooperative agreement with the British Government.

The most important commercial source of nitrate of potash is from nitrate of soda by treatment with potassium chloride. A hot solution of potassium chloride is treated with the required amount of nitrate of soda, the two materials combining to form nitrate of potash and common salt. On evaporation of the solution, the salt being the more insoluble precipitates out and is removed from the solution. When the solution has reached a certain density, the clear liquor is drawn off into crystallizing tanks. Here it is allowed to cool while