pine Islands. Solid bitumens occur in West Virginia and Oklahoma, but the most important deposits are in Utah and western Colorado.

Natural asphalt, as suitable for paving purposes as that from Trinidad and Venezuela, is not found in the United States; but by adding asphaltic residues from petroleum the natural hard asphalts and solid bitumens available in this country can be made into efficient substitutes, which guarantee the independence of the domestic paving industry should the foreign supply of asphalt be cut off.

Manjak is imported from Barbados for use in the varnish industry. No deposits of manjak of commercial importance are known in the United States, but efficient substitutes are available in the high grade gilsonite and elaterite deposits of Utah.

Ozokerite, a native paraffin wax that has been imported for many years from Galicia, occurs in Utah, but because of the cost of extracting the mineral and of transporting it to eastern markets the deposits have remained undeveloped. For all practical purposes paraffin wax prepared as a by-product of petroleum refining is an acceptable substitute for refined ozokerite.

ASBESTOS.

The United States is not a large producer of asbestos, but there are asbestos deposits in Georgia, Arizona, California, Virginia, and Vermont. The domestic production amounted to 7,600 tons in 1911, while the imports, largely from Canada, amounted to ten times this quantity. The Canadian asbestos mines at Thetford, Quebec, are the largest in the world, and the United States absorbs nearly three-fourths of their output. This country exports considerable quantities of articles manufactured from asbestos.

Asbestos is the most important fireproofing material known. Its fibrous structure adapts it to a wide range of applications from woven fabrics, such as theater curtains and articles of clothing, to various forms of asbestos board and paper, pipe covering, shingles, plaster, etc. For a few purposes asbestos finds a competitor in magnesite, which is also a refractory material, but for most of the purposes to which it is applied it is practically without a rival.

CHEMICAL MATERIALS.

PHOSPHATE ROCK.

Thirty-five years ago the production of phosphate rock in the United States was 211,000 long tons. During 1913, production amounted to 3,111,000 long tons and exports to 1,366,000 long tons, or nearly 44 per cent of the total production marketed. Thus it will be seen that in 34 years the production of phosphate rock in the

United States has increased nearly fifteenfold. The accompanying curve, fig. 9, shows graphically the marketed production and the exports of phosphate rock during the past 10 years.

1904- 1905 1906 1907 1908 1909 1910 1911 1912 1913

FIG. 9.-Curve showing production and exportation of phosphate rock, 19041913. (Note that exports tend to diminish compared with production.)

As the figure shows, a very large part of the phosphate rock is shipped abroad, but the amount exported, compared with the total quantity marketed, shows a tendency to diminish. The quantity of phosphate rock or phosphate-bearing compounds imported into the United States for use as fertilizer is exceedingly small.

The known phosphate producing areas in the United States are as follows: (1) In middle Tennessee; (2) along the western side of the Florida peninsula, extending 25 miles inland; (3) on the South Carolina coast, chiefly near Charleston; (4) a large area in Utah, Idaho, Wyoming, and Montana. In addition, there are important deposits in the Blue Grass region of Kentucky, and less well-known areas in Arkansas and elsewhere. Thus it will be seen that the important phosphate-bearing areas are not confined to any one district of the country but are widely scattered and are available to all parts of the United States. Most of the rock exported has been produced in Florida and Tennessee.

Phosphate rock is used chiefly in the manufacture of fertilizers, especially the so-called complete fertilizers. For this reason it is a commodity of vital concern to the farming industry in the United States and hence to all the people. There are no substitutes for it. Consequently the quantity of phosphate rock available for future

8161°—INT 1915—vol 1- -13

generations and the efficient utilization of this supply are of paramount interest and importance.

Calculations of the probable future life of our phosphate reserves have been made, but these calculations are subject to change as new factors arise for consideration. Among the more important of the new factors, that will tend to prolong the life of the deposits, especially those in the East, is the extensive introduction of improved mining and milling methods, by which deposits that were thought to have been worked out and tailings dumps and waste ponds from old phosphate mills are being reworked, and lower-grade rock is being mined at a profit.

Through the introduction of such methods deposits in Tennessee will yield rock for many years to come and the experience gained in Tennessee will be applied in the practically virgin central Kentucky field.

Nearly all the "hard rock" mined in Florida is shipped abroad. The life of the hard-rock field has been estimated at 25 to 100 years, depending on the rate of production. Very few new deposits are now being discovered and many of the old ones are now worked out. In washing the phosphate rock there have been large losses. In time some of the refuse will be retreated and losses will be greatly reduced. The mining of pebble rock in Florida has grown rapidly and in 1913 the output exceeded 2,000,000 tons. The deposits of this rock are so large that their end is not in sight.

A recent estimate of the phosphate rock in the South Carolina field indicates the presence of 5,000,000 tons of 60 per cent rock in the ground which will become workable when improved machinery is devised. Other estimates have been larger. The output of South Carolina rock in the past two years has been slightly in excess of 100,000 tons, and at this rate the field may be expected to last at least 50 years.

The known extent of the western phosphate reserves has been greatly increased in the past few years through the work of the United States Geological Survey which has resulted in including more than 2,660,000 acres of land in the phosphate reserves of the United States. Most of this land is in Idaho and Wyoming; some in Montana and Utah, and some in Florida. The work of surveying the western phosphate lands is still going on. Clearly, however, the United States is independent of the rest of the world as regard phosphate rock, and can produce enough for its own needs for an unknown number of years to come.

Phosphate rock is relatively insoluble, and the phosphoric acid it contains is converted into the easily soluble form, and thereby made readily available as plant food by treating the rock with acid. A cheap powerful acid is needed, and thus it happens that an

important factor in the development of the phosphate industry is the use of plants for recovering sulphuric acid from the fumes given off in roasting and smelting sulphide ores. This acid being recovered partly in efforts to prevent damage from smelter smoke, is produced in large quantities and is sold cheaply. At present there is no market for all the acid that could be produced, but the presence of large smelting plants within a relatively short distance of the phosphate fields of Tennessee and of the West assures an adequate supply of cheap superphosphate for agriculture.

In the eastern fields the waste in mining is large. In some places more phosphate is discarded than is saved. No doubt most of this low-grade waste material will eventually be utilized, as some of it is already being put to use. The progress made in reworking waste material in Tennessee has been indicated.

Considering the industry as a whole, the progress toward more efficient methods of mining and treating the rock has been great. Low-grade deposits are becoming of commercial value; waste dumps are being rewashed, and old mines reworked at a profit. Among the possibilities of the future are the possible introduction of chemical methods whereby low-grade deposits can be converted into concentrated forms and shipped at a profit, the direct application of lowgrade phosphate rock to the land, and the utilization of other sources of phosphate, for example, the mineral apatite and phosphate-bearing slags, large quantities of the latter now being wasted.

SULPHUR, PYRITE, AND SULPHURIC ACID.

Through the inventive genius of an American, Herman Frasch, the United States occupies the dominating position in the sulphur industry of the world, and Italy (Sicily), which formerly held this position, now ranks second. By the Frasch process superheated water is forced into the sulphur deposits and pure molten sulphur is pumped to the surface. From an output of a few thousand tons in 1900, there was a marketed production in 1914 of 328,000 long tons, valued at nearly $6,000,000, and in the same period imports from Sicily to the United States dropped from 168,000 tons to less than 1,000 tons, although the total Italian exports were approximately 340,000 tons. The total imports amounted to 26,000 tons, or only 8 per cent of our own production. This foreign sulphur came chiefly from Japan to the Pacific coast.

The United States not only produces enough sulphur for home consumption, but has begun to place sulphur on the European market. In 1909 the United States exports of sulphur amounted to 37,000 long tons and in 1914 nearly 100,000 tons, an increase of 270 per cent.

The principal sulphur deposits are along the Gulf coast in Louisiana and Texas. The conditions which obtain at Sulphur, La., and Freeport, Tex., exist at many other places in the coastal plain region of these two States, and doubtless other deposits of sulphur will be revealed in the future by deep drilling.

There are going on in the United States at present certain investigations which may prove of far-reaching importance in the sulphur industry, and by them may be illustrated the old adage that "necessity is the mother of invention." Two Americans, S. W. Young and William A. Hall, during the past few years have been working on processes whereby destructive fumes from smelters-the so-called sulphur fumes-will be converted into sulphur and at the same time rendered harmless, thus accomplishing two most desirable results.

The processes of Hall and Young are in a different class from those now extensively employed in the manufacture of sulphuric acid from smelter gases. Destructive smelter gases for years have been a source of expense to smelter men and a pronounced annoyance to farmers and others living near the smelters. By the utilization of these gases in the manufacture of sulphuric acid they cease to be nuisances and become a source of wealth. One copper-smelting plant in southeast Tennessee has perhaps the largest sulphuric-acid plant in the world, and acid is now being made at copper smelters in Arizona and California, while by-product acid from the sulphur fumes of zinc smelters is made at places in Pennsylvania, Ohio, Indiana, Illinois, Kansas, and Colorado. The production of acid from smelter gases in 1911 was 548,000 tons, and in 1914 it was 951,000 tons, the remarkable growth of a profitable industry from what was a waste product.

Pyrite, the mineral used primarily in making sulphuric acid, was produced in the United States to the extent of 341,000 tons in 1913. Imports were 851,000 tons, chiefly from Spain, Portugal, and Canada. The great difference between production and imports is explained by the fact that most of the pyrite imported is used along the Atlantic seaboard, and by reason of low ocean freights can be imported more cheaply than it can be produced at home. This does not mean that we are deficient in pyrite resources, for the pyrite deposits in the United States can furnish a much larger tonnage.

Pyrite is a by-product in coal mining in several States, notably in Pennsylvania, Ohio, Indiana, and Illinois. Formerly it was discarded, but in 1914, 31,500 tons, valued at $84,000, were produced in the three States. This is a domestic source of pyrite which has hardly been touched and could be made to yield large returns should the necessity arise. At present, where no trouble is taken to save and use this pyrite, it is thrown on the culm dumps, to become not only a waste but a nuisance.