harden in molds. First-class chicle is nearly white when well cooked, fresh and clean, but turns reddish when overcooked. Certain trees also yield a primarily reddish gum. Crude chicle as it leaves Mexico contains about 50 per cent water, some of which is lost in transportation, and as imported, contains about 40 per cent water. Its chief use is in the manufacture of chewing gum, for which it is refined by grinding, straining, and drying.

Imports.-Prior to the act of 1913 all chicle was dutiable at a uniform rate. In 1913 the import was 6,920,415 pounds, valued_at $3.059,116, and yielded a revenue of $692,041. From July 1 to October 3, 1913, 7,998,186 pounds, but for the remainder of the fiscal year 1914 only about 1,500,000 pounds of both crude and refined chicle were imported. Since 1914 the imports of crude chicle have increased from 2,465,400 pounds in 1915 to 4,580,501 pounds, valued at $2,076,143, and yielding a revenue of $687,075 in 1918. The import of refined chicle increased from 1,934,760 pounds in 1915 to 3.935.093 pounds, valued at $2,371,834, and yielded a revenue of $787,018 in 1917. In 1918 (fiscal year) the import of refined decreased to 2,028,367 pounds. Later statistics follow:

Exports.-Statistics not available.

Suggested changes.-Attention is called to the classification of various gums used as substitutes in part or as adulterants for chicle in the manufacture of chewing gum. These gums would be exempt from duty under paragraph 1577, in H. R. 7456, whereas chicle is dutiable under this paragraph. Such treatment of these gums, related to chicle, in paragraph 1577, would tend to encourage the importation of these inferior gums.

PARAGRAPH 24.

SENATE AMENDMENTS.

H. B. 7456.

PAR. 24. Chloral hydrate, terpin_hydrate, thymol, urea, and glycerophosphoric acid, and salts and compounds of glycerophosphoric acid, 25 per centum ad valorem.

Description and uses.-Chloral hydrate is a white crystalline solid of sharp taste used chiefly as a sleep-producing drug. Chloral is converted into chloral hydrate by the addition of water, and is also combined with other substances to form various drugs used for neuralgia and as sleep producers.

Production.-Chloral hydrate is manufactured by treating ethyl alcohol (grain alcohol) with chlorine gas and subsequently with sulphuric acid and water. The use of denatured alcohol is lawful for this purpose.

Prior to the war its manufacture was attempted here from taxpaid alcohol but discontinued because of the reduction in price of the German product. After the war its manufacture was resumed at St. Louis, Mo., and at Midland, Mich., upon a scale sufficient to supply domestic needs.

Imports in 1914 were 644 pounds. Later statistics follow:

Description and uses.-Terpin hydrate is prepared by the action of nitric acid and alcohol on turpentine oil. It crystallizes in colorless, rhombic prisms, has a slightly aromatic odor and a bitter taste, and is used chiefly as a medicinal.

Production.-Terpin hydrate is manufactured in the United States by several firms, but data on production are lacking.

Imports.-The largest imports during any one year (1914) were 6,929 pounds, valued at $1,020, yielding a revenue of $255. Over 92 per cent of these imports came from Germany. A few small shipments only have been imported in 1921. Exports.-Statistics not available.

THYMOL.

(See Survey A-6.)

Description and uses.-Thymol is a chemical derived from ajowan seed, native to India, Egypt, Persia, and Afghanistan. It is used in the treatment of disease, as an antiseptic wash, in some brands of tooth pastes, in preparations to destroy molds and certain parasites, as the hookworm, and as an embalming fluid for corpses and anatomical specimens.

Production.-Thymol has been produced domestically from imported ajowan seed, although before the war it was chiefly imported from Germany, which had a virtual monopoly in its manufacture. Because of the scarcity of ajowan during the war, experiments have been undertaken on several American plants with the view to obtaining a domestic supply. Present production is not known. Thymol is manufactured to some extent in England and India.

Imports for 1914-1918 show an average of 12,199 pounds, valued at $33,336; revenue, $8,334. Later statistics follow:

Description and uses.-Urea is the commercial name for the substance which is found naturally in the urine as well as in the blood, milk, and other animal fluids. It crystallizes in transparent, colorless, four-sided prisms. Urea forms salts such as the nitrate, oxalate, acetate, citrate, and hydrochloride, used chiefly as medicinals. Its largest use is as a stabilizer in pyroxylin plastics.

Production.-Urea has been manufactured in the United States only since the latter part of 1916. It is made by treating calcium cyanamide with water in the presence of a mineral acid. It may also be prepared from phosgene gas and ammonia.

Calcium cyanamide, the raw material of urea, is manufactured by an American firm with a plant located in Canada. Successful manufacture requires cheap electric power.

Domestic manufacture of urea resulted from the failure of German supplies. The annual production is not known, but is estimated not to exceed 200,000 pounds.

Urea is made in Germany from ammonium cyanate-a by-product of the cyanide industry-by treating with boiling water.

Imports. The largest quantity of urea imported since 1914 was 79,192 pounds, valued at $32,498, with a revenue of $8,125 in 1916. Imports since 1917 have been as follows:

Description and uses.-Glycerophosphoric acid is the substance formed when glycerol (glycerin) and phosphoric acid are heated together. It is a clear, colorless liquid when made, but decomposes rapidly and changes color. It is rarely obtained pure and is of little importance commercially, but its salts-sodium, calcium, and potassium glycerophosphates are used as medicinals. Glycerophosphoric acid is also used in medicine when combined with iron, manganese, quinine, and strychnine.

Production. The production of glycerophosphoric acid and its salts is carried out by several manufacturers of a general line of pharmaceuticals, there being two companies, in New York State, two in St. Louis, and one in Philadelphia.

Imports show a decrease in quantity since 1914, but an increase in value. In 1917, 5,853 pounds of the acid and its salts were imported as compared with 24,789 pounds in 1914, 15,933 pounds in 1915, and 7,668 pounds in 1916. The revenue obtained during the maximum year, 1914, was $5,767. Imports since 1917 have been as follows:

Important changes in classification.-Items omitted from this paragraph but contained in paragraph 18, act of 1913, have been transferred to the coal-tàr paragraph.

PARAGRAPH 25.