The utilization of the residues from the roasting of pyrite is another commanding problem. Pyrite contains 53.4 per cent sulphur and 46.6 per cent iron. Roasting removes nearly all the sulphur, but about 2 per cent remains in the cinders and prevents that from being a valuable iron ore for direct smelting. Now this cinder is roasted to a clinker, removing the sulphur and making the clinker a firstclass iron ore. This method of utilizing a waste product is in use in southwest Virginia, and without doubt its use will become general. Sulphuric acid is a commodity so extensively used in the manufacture of other chemicals that it has come to be regarded as a criterion or gauge of the activity of the country in chemical manufactures in general. It is probably used for a greater variety of purposes than any other chemical, one of the more important being the manufacture of superphosphate, used in artificial fertilizers, from phosphate rock. The total sulphuric acid production in the United States in 1914 was 3,762,000 tons, valued at more than $24,000,000. Although under present commercial conditions governing the manufacture of sulphuric acid the United States imports pyrite to be used as a source of acid, this country is absolutely independent of the world as regards sulphuric acid itself. One smelter in Montana produces sulphur gases sufficient to make more sulphuric acid than is required by the fertilizer industry of the whole country. Yet under the special demands of the present year there is a shortage of sulphuric acid.

POTASH SALTS.

Practically all the potash salts used in the United States have come from Germany, the imports amounting to $15,000,000 annually. The magnitude of the value of the imports, which include fine chemicals imported by the pound and crude salts imported by the ton, is significant. For many years the United States has been dependent on Germany for this commodity, of which Germany has had a natural monopoly.

The fertilizer industry consumes large quantities of these German potash salts. Other industries in which potash salts are consumed in large amounts are the soap, matchmaking, glass making, photographic, pharmaceutical, and the chemical industries in general. The list of potash chemicals is large and very important. These chemicals are used as alums in the dyeing industry as a mordant, and also by paper and leather makers, in pigment lakes, in medicine, etc., in making cyanide which is used in assaying and in metallurgical operations, especially the recovery of gold from low-grade ores and tailings; and red and yellow prussiate of potash are used in making dyes and for other purposes; in the manufacture of explosives; bleaching materials; and in making other important chemicals.

As a result of the European war prices have greatly advanced. High-grade chloride of potash used in fertilizer now brings $220 and upward per ton, as compared with approximately $40 per ton at the outbreak of hostilities abroad.

Since the complete dependence of the United States on Germany for its potash salts was forcibly impressed upon the people of this country in a controversy that arose about five years ago, the Government has been actively engaged in searching for potassium salts in this country. This search is still going on. The following possible sources of potash salts are being investigated: (1) Saline residues; (2) natural and artificial bitterns; (3) alunite and similar minerals; (4) the igneous rocks and minerals like the potash-bearing feldspars; (5) the greensand marls found in large quantities in New Jersey, Kentucky, Tennessee, and other States; and (6) organic sources, such as seaweed, molasses residues, wool scourings, etc. Experiments on nearly all these sources have been conducted or are in progress and reports indicate that to a certain extent, at least, the United States soon may be relieved of absolute dependence on foreign sources of potash salts.

The Geological Survey and the Bureau of Soils jointly called attention in 1912 to the importance of the deposits in Searles Lake, Cal., as a source of potash salts, and though no potash salts have yet been produced at Searles Lake the potash content of this lake is well determined.

Some potash salts, however, have been shipped this year from an alkali lake in Nebraska, reported on in 1913 by the Geological Survey.

One of the promising sources of commercial supplies of potash salts in the United States is the group of alunite veins that has been prospected and developed in the vicinity of Marysvale, Utah, during the last four years. Shipment of potassium sulphate from this area began in October. With the extraction of potash from alunite alumina is secured as a by-product, the first known western source of an aluminum ore.

The possibility of obtaining potash salts from feldspar and other silicates is being eagerly investigated by American inventive genius. In this connection the United States Geological Survey publications on potash-rich igneous rocks and potash-bearing "tailings" from porphyry copper ores have proved to be of importance.

A portion of the Geological Survey's special appropriations has been spent in deep drilling in the arid parts of the West. No deposits of potash salts have been found, but the work is still going on. Conclusions based on the work done have eliminated certain basins from those likely to contain potash salts. Such conclusions, though negative, are of real value to the American citizen bent on ex

ploring for potash salts in the great American desert. The so-called red beds of the Southwest may also be a possible source, and are being given a thorough geological study, aided by test wells.

The problem of a domestic supply of nitrates is in much the same category as the domestic supply of potash salts. We are entirely dependent on Chile for our supply of natural nitrates, the imports from that country amounting to about $20,000,000 annually. Chile occupies the unique position of being the sole supply of the naturally occurring nitrate, as does Germany in the case of potash salts.

Between 20 and 25 per cent of the nitrate imported finds its way into fertilizers. A part of it is converted into nitric acid and potassium nitrate, used in making gunpowder and other explosives. Both the potash and the nitric acid used in making potassium nitrate are imported. The nitrates are also used in making matches and fireworks, in the manufacture of sulphuric acid, in metallurgical and analytical operations, and in curing meats.

Nitrates can be made from the nitrogen of the air by electrolytic processes. This is now being done, but on a very small scale within the limits of the United States, although successfully on a large scale in Norway. Nitrogen compounds used in fertilizers are now being made at Niagara Falls, Canada, and are being imported into the United States. These take the place of nitrates in fertilizers. The manufacture of nitrates by electricity requires expensive installation and an abundance of cheap water power. To render the United States independent in the matter of nitrates and nitric acid, factories must be installed, and it is very doubtful whether, in case of need, the United States could begin the manufacture of the necessary supply of nitrates without the loss of much valuable time.

By the substitution of by-product coke ovens in place of beehive ovens there becomes immediately available large quantities of ammonium sulphate, the nitrogen constituent of which might be used in the fertilizer industry.

SALT, BROMINE, AND CALCIUM CHLORIDE.

The marketed production of salt in the United States in 1914 was 4,900,000 short tons, valued at $10,000,000, which is about seven times the production and value of this commodity in the United States in 1800. (See curve of production, fig. 10.)

The United States furnishes very nearly all the salt consumed by our people. For many years the country has been able to supply the domestic demand, since the present capacity of both mines and manufacturing plants is 20 to 25 per cent in excess of the present output. Many plants now working at partial capacity, or entirely shut down, could resume operations on short notice.

Great strides have been made in recent years in methods of making high-grade salt both by the grainer and vacuum-pan processes. The mechanical grainers, in which the brine enters the plant and in which the salt is not touched by human hands till it is almost ready for shipment, are marvels of ingenuity. Fine table salt is now made almost exclusively by the vacuum-pan process, which has so reduced the cost of making fine salt that the old-time methods have passed into history.

The salt-producing States are scattered throughout the country from New York to California and 15 States reported a production

30

25

20

Quantity of salt in millions of barrels of 280 pounds each

Value, in millions of dollars, of salt produced in United States

1890

1895

FIG. 10.-Curves showing growth in quantity and value of salt produced in the United States, 1880-1914.

in 1914. Salt of all grades is made, from the rock salt to the finest grades for table and dairy. Salt is produced from both natural and artificial brines; from the water of Great Salt Lake and the Pacific Ocean; while in New York, Michigan, Kansas, and Louisiana it is mined as rock salt. There are a number of wells in western New York and southern Michigan where fresh water is run by gravity or pumps into the salt beds and the brine run out by the excessive freshwater head. This system has resulted in exceedingly low-mining costs. It may be truly said of this commodity that the supplies are

1880

inexhaustible and that the United States can not only supply her own needs but those of the world.

Bromine is obtained in connection with the production of salt in Ohio and West Virginia and to a certain extent in the Saginaw Valley, Mich. In Michigan the bromine is marketed in the form of fine chemicals. That produced in West Virginia and Ohio is largely shipped abroad and returned to the United States as fine chemicals and we pay the costs. Along the Ohio River, where there is cheap rail and water transportation, where there is an abundance of cheap coal and gas, and where salt and bromine occur naturally, it is to be regretted that a valuable material like bromine has to leave the country to be made into fine chemicals. Here is an opportunity for the American chemist.

Calcium chloride is also made from the natural brines in the Ohio Valley and thus practically every constituent in the brines can be saved and turned into profit. The large quantities of this chloride formerly wasted in connection with the manufacture of soda are now being used in part and it is hoped that new uses for that which is now wasted will soon be found by the American chemist.

FLUORSPAR.

The fluorspar industry of the United States has shown a steady growth from a production of 4,000 short tons in 1883 to 116,000 tons, valued at $736,000, in 1913. This notable gain, shown graphically in fig. 11, has resulted largely from the growth of the open-hearth process of steel manufacture, which absorbs about 80 per cent of the fluorspar produced. Fluorspar is used also as a flux in blast furnaces, iron foundries, and silver, copper, and lead smelters; in the manufacture of fluorides of iron and manganese for steel fluxing; in the manufacture of glass and enameled and sanitary ware and of hydrofluoric acid; in the production of aluminum; in the electrolytic refining of antimony and lead; and for many other purposes.

The increase in the home production and the imposition of a tariff on fluorspar in 1909 have resulted in a marked decrease in the amount brought in from foreign countries, and in 1913 only about 23,000 short tons were imported, compared with the 116,000 tons produced at home. The imports come almost entirely from dumps of abandoned lead mines in England, and amount to over 55 per cent of the total English production. The English product entering at New York is able to compete with domestic "spar" as far west as Pittsburgh.

There is an adequate American supply to meet all demands in case of extreme necessity. In 1913 the output came from Illinois, Kentucky, New Mexico, Colorado, New Hampshire, and Arizona, named