QUICKSILVER.

SUMMARY.

IMPORTANCE OF THE INDUSTRY.

Quicksilver is an essential component of all mixtures for detonating high explosives. No satisfactory substitute has been found for military use. It is used in drugs, and is the most satisfactory ingredient of antifouling paint for ships' bottoms, in addition to its numerous technical and scientific uses that are less direct, though not unimportant factors in military operations.

Up to 50 per cent of the normal peace-time consumption of quicksilver is as the essential constituent of blasting caps. By virtue of this use it is a factor- in the production of all metals and minerals and in most excavation and general construction work. In no single application is the amount required very great, but many industries would be crippled were they unable to secure the small but vitally necessary amount required.

FOREIGN AND DOMESTIC RESOURCES.

The domestic deposits of quicksilver ore are low grade and erratic. metal content of the ore mined in the United States is

The average less than one-half of 1 per cent. The supplies of such material are large, but even more extensive supplies of ore are found in Spain, where the metal content averages 8 per cent and over. Italy and Austria have enormous cheaply minable reserves that are two to three times richer in metal than the American deposits.

DOMESTIC SUPPLIES.

Quicksilver production was at a low ebb in the United States at the beginning of the war, and increasing amounts of the metal were being imported to supplement the dwindling, unprofitable output of the domestic mines. Relieved from foreign competition and stimulated by high prices, the domestic output increased to large proportions. The output in 1918 was 32,883 flasks (of 75 pounds), at least 50 per cent more than the normal peace-time consumption of the metal in the United States; in 1919, 21,348 flasks. In 1920 the poor market and continued high cost of labor and supplies had a depressing effect on the industry. Production was further reduced by the destruction, in June, of the plant of the largest producer. FUTURE COMPETITIVE CONDITIONS.

With the return of normal conditions it is believed that Spanish metal, which is controlled by British interests, will be imported and will depress the price in the American market, which during 1918 was 2.5 times the average price before the war, to below the present cost of production of most of the domestic producers. However, sporadic production of quicksilver would doubtless continue in the United States even in the face of such competition.

THE QUICKSILVER INDUSTRY.

DESCRIPTION.

Quicksilver, or mercury, is a silver-white metal, which remains liquid at ordinary temperature. It freezes at minus 38.9° C., boils at 357° C., and is 13.6 times heavier than water. It is marketed in flasks containing 75 pounds each.

Ores.-About 25 minerals containing mercury have been identified, but of these only three are of commercial importance.

Cinnabar is the well-known cochineal-red mercuric sulphide (HgS). When pure, it contains 86.2 per cent of the metal. It is soft (hardness 2 to 2.5) and heavy (specific gravity 8.0 to 8.2). The occurrence is crystalline, massive, or earthy. Its most common associates in ores among other metallic minerals are pyrite (or marcasite), sulphides of antimony or arsenic, sulphur, and, less frequently, sulphides of copper and native gold. Frequent gangue minerals are calcite; quartz, chalcedony or opal; barite; bitumens; and, less often, fluorite. Cinnabar in a more or less pure state is the chief ore of quicksilver and almost the only ore mined in the United States.

Metacinnabarite has the same chemical constitution, when pure, as cinnabar, but is usually massive, gray black in color, and slightly harder.

Native quicksilver.-The native metal, occurring as minute drops or in cavities, and also as an amalgam with silver and other metals, is a frequent associate of the other ores. It is usually considered to be a natural reduction product of cinnabar or metacinnabarite.

USES.

As the only metal that is liquid at ordinary temperatures, quicksilver has unique and special uses in the metallic state. Its Its comparative chemical inertness together with its weight and mobility, make it valuable for many instruments. It alloys readily with certain other metals forming plastic amalgams. The most important use is as fulminate in blasting caps and other detonators. Both the chlorides of the metal are used in medicine, and surgery, and the oxide by conversion into mercuric chloride by the salt in sea water provides the active poison in antifouling paint for ships' bottoms. Nonmilitary uses.--Mercury is employed in making drugs, chemicals, fulminate for blasting caps, red oxide for antifouling paint,