IODINE.

(See Survey A-9.)

Description and uses.-Iodine, a nonmetallic element, is a grayish or purplish-black solid which volatilizes easily, giving off a violetcolored vapor. It does not occur free in nature, but its salts are widely distributed in small amounts and are always present in sea water and in some mineral springs. The principal source of iodine is found in sodium nitrate beds of Chile. Iodine is used directly and in the form of iodine compounds in medicine. The compounds are also employed in photography. About 80 per cent of the domestic consumption is probably made into sodium and potassium iodides. Crude iodine is provided for in paragraph 1588, page 1335.

Production of iodine is not commercially important in the United States, although small amounts have been produced from kelp on the Pacific coast. Exports of iodine from Chile prior to the war were about 1,000,000 pounds, increasing to a maximum of 3,000,000 pounds in 1916 and then decreasing to 2,000,000 pounds in 1918. Chile's potential production as a by-product of nitrate refining is three to four times these amounts. Output in Japan tripled from 1913 to 484,138 pounds in 1917.

Imports of crude iodine are chiefly from Chile. These increased from 195,030 pounds in 1914 to 1,726,723 pounds in 1917, but dropped to 200,448 pounds in 1918. Imports from Japan were 1,500 pounds in 1915, but increased to 53,092 pounds in 1918. Recent statistics of imports of crude iodine follow:

Imports of resublimed iodine have been negligible; the maximum was 15,550 pounds in 1918 (calendar year), valued at $49,583. Exports. Statistics not available.

Important changes in classification.-Resublimed iodine is exempt from duty under the act of 1913 (par. 515).

BROMINE AND BROMINE COMPOUNDS.

(See Survey FL-8.)

Description and uses.-Bromine is one of the chemical elements. It is a dark reddish-brown, highly corrosive liquid, giving off heavy, irritating vapors. It is produced here almost entirely from natural brine in connection with the salt industry. Bromine is used in the manufacture of certain coal-tar dyes and bromine compounds; the latter are employed principally in photography and medicine. During the World War bromine and some of its compounds were used in gas warfare.

Owing to the corrosive nature of bromine and consequent dangers attending transportation, it enters commerce largely in the form of its salts-sodium bromide, potassium bromide, and ammonium bromide.

Production of bromine in the United States in 1913 was 572,000 pounds, increased to a maximum of 1,854,971 pounds, valued at $1,234,969, in 1919, and then decreased to 1,160,584 pounds, valued at $745,381, in 1920. Germany is the only other important producer and prior to the war ranked first, with an output in 1912 of 1,909,184 pounds. Domestic figures include bromine content of various bromine compounds, such as sodium and potassium bromide. Production in the United States is as a by-product of the salt industry. and in Germany a by-product of refining potash salts at Stassfurt.

The output of sodium bromide from 1918 to 1920 has been around 500 short tons, valued at $500,000. It is produced by absorbing free bromine in a solution of sodium carbonate. The production of potassium bromide in 1918 was 666,119 pounds, of which 616,232 pounds, valued at $551,079, were sold.

Import statistics of bromine and its compounds are not available except for 1914, when only 361 pounds of potassium bromide, valued at $200, were imported.

Exports.-Large quantities of bromine were exported to Great Britain, France, and Italy in 1918 during the war, at which time these countries were largely dependent on the United States.

Important changes in classification.-Bromine is provided for specifically in the free list of the act of 1913 as "bromin" (par. 433). Because of its corrosive nature, bromine is usually shipped in the form of its various compounds. The provision for bromine was broadened by amendment on the floor of the House of Representatives so as to include the various compounds of bromine.

H. R. 7456.

PARAGRAPH 44.

PAR. 44. Lead: Acetate, white. 31 cents per pound; acetate, brown, gray, or yellow, 2 cents per pound; nitrate, 2 cents per pound; arsenate, resinate, and all other lead compounds not specially provided for, 30 per centum ad valorem.

SENATE AMENDMENTS.

Description and uses.-Lead acetate, often called sugar of lead, is the most soluble of the common lead salts. It is on the market as (1) "white" or pure acetate of lead and (2) "brown" (also "gray or "yellow") acetate of lead, an impure grade of the lead salt. White acetate of lead is also known and sold as "crystals," while the brown grade is called "granular." Other qualities of both the white and brown acetate of lead are sold as "broken or "broken cakes."

Lead acetate is one of the most important of lead salts. It is used in the manufacture of pigments and in the preparation of alum mordants for dyeing cloth and some fibers; in medicine, in the preparation of insecticides, and in chemical laboratories as a reagent. The basic lead acetate is used to some extent for weighting silk.

Production-Lead acetate is usually made by the action of acetic acid upon litharge. In the production of "brown" sugar of lead, pyroligneous acid (crude acetic acid or wood vinegar) is used. The brown color is due to the dissolved impurities in pyroligneous acid. Lead acetate may also be made directly from metallic lead or white lead. Basic lead acetate is prepared by dissolving litharge in acetic acid. The output in 1919 (preliminary figures) was 4,183,600 pounds, valued at $552,400.

Imports of lead acetate prior to the war were sporadic and negligible compared with domestic production. They reached a maximum of 128,433 pounds in 1914. During the war and through the first nine months of 1921 there were practically no imports of lead

Description and uses.-Lead nitrate is the compound formed by the action of nitric acid on litharge, and usually costs more than lead acetate, due to the higher cost of nitric acid. It is used in dyeing and calico printing, for the production of mordants, in insecticides, in the manufacture of matches and lead chromate pigments.

Production.-Lead nitrate is made by dissolving some form of lead, usually litharge, in dilute nitric acid and crystallizing the lead nitrate from the solution. Statistics are combined with "all other lead compounds," page 130.

101744-229

Imports of lead nitrate prior to the war were less than 200,000 pounds, and during the war years practically ceased. Since the war, the maximum import has been about 4,000 pounds during the first nine months of 1921.

Exports.-Statistics not available.

LEAD ARSENATE.

Description and uses.-Lead arsenate is a white, crystalline compound, which is extremely poisonous, and hence is used chiefly in the manufacture of insecticides.

Production. It is made by the action of a soluble lead salt on a solution of sodium arsenate, with subsequent concentration and crys tallization. Domestic production in 1914 amounted to 8,641,900 pounds, valued at $511,700. In 1919 (preliminary figures) the output was 11,465,800 pounds, valued at $2,090,300.

Imports and exports.-Statistics not available.

Important changes in classification. Mentioned specifically for the first time.

LEAD RESINATE.

Description and uses.-Lead resinate is one of the most important of the paint and varnish driers. It is a yellowish white, poisonous paste, and is used also as a drier in printing inks. Contrasted with manganese and cobalt driers, lead resinate gives toughness of film with no darkening effect, rather than speed in drying. There are two grades, precipitated and fused.

Production. The precipitated grade is made by heating a solution of lead acetate and rosin oil. The fused grade is made by heating litharge and rosin. Since the war domestic manufacturers have been able to fill all demands.

Imports in 1914 were 61,107 pounds of precipitated lead resinate, valued at $1,099, and 56,560 pounds of the fused resinate, valued at $4,799. Imports for recent years are not available, but the quantity has not been large.

Exports.-Statistics not available.

Important changes in classification.-New specific provision.

ALL OTHER LEAD COMPOUNDS.

Forty-six different lead compounds were imported during 1914, but only 13 of these in amounts greater than $100 in value. There are a few salts of lead not specially provided for in the act of 1913 which are commercially important. Lead salts are used as reagents in chemical laboratories, in paint driers, and for the manufacture of rubber, but the quantities required are usually small.

Production in the United States of lead acetate, lead nitrate, and other lead compounds for the calendar year 1914 was 7,290,936 pounds, valued at $474,430. In 1919 (preliminary figures) the output of lead salts (exclusive of arsenate and acetate) was valued at $335,500. Germany, Great Britain, Belgium, and France manufac ture lead salts and other lead components in considerable quantities.

Imports of all other lead compounds in 1914 were 102,899 pounds, valued at $9,348. Imports decreased greatly during the war, and since 1917 have been as follows:

Description and uses.-Licorice extract is a dried decoction of licorice root. It is sold as a "paste" in cases of 250 to 400 pounds and as stick or roll licorice in small cylinders 6 to 9 inches long and one-half to 1 inch in thickness. The paste is used almost entirely in chewing tobacco, and the roll and stick forms in pharmacy and confectionery.

Production.-Licorice extract is extensively produced in Italy. Lesser amounts are manufactured in Russia, Spain, Turkey, and other European countries. It is also extensively manufactured in America from the imported root, and it is prepared chiefly by tobacco manufacturers for their own use. American production is characterized by a higher type of mechanical process than that used abroad, which is chiefly dependent upon cheap hand labor. The root yields about one-fifth of its weight in extract. The production of extract in the United States may be estimated from the root imported to be about 17,000,000 pounds annually. Imports of licorice extract are usually of a high grade, and are used mainly in pharmacy.

Imports come chiefly from Spain. They have continued to increase under the successively decreasing rates of recent acts. Trade in this product has also grown at the expense of that of licorice root, owing to the greater bulk of the latter and the shipping restrictions imposed