Imports of cork bark and waste amounted to $6,338,330 in 1920, the imports of manufactures of cork amounted to $1,969,203, while the value of domestic exports was $2,022,174.

1 Products of establishments engaged in the manufacture of various articles from cork, including such products as life preservers and cork board for insulation, cork tips, but comprising chiefly bottle corks. În addition, products to the value of $54,353 were reported by establishments assigned to other industries. (Census of Manufactures, 1914.)

2 Exports for calendar years 1918 and 1919.

GENERAL INFORMATION.

1913 TARIFF PARAGRAPH.

340. Cork bark, cut into squares, cubes, or quarters, 4. cents per pound; manufactured cork stoppers, over three-fourths of an inch in diameter, measured at the larger end, and manufactured cork disks, wafers, or washers, over three-sixteenths of an inch in thickness, 12 cents per pound; manufactured cork stoppers, three-fourths of an inch or less in diameter, measured at the larger end, and manufactured cork disks, wafers, or washers, three-sixteenths of an inch or less in thickness, 15 cents per pound; cork, artificial, or cork substitutes manufactured from cork waste, or granulated corks, and not otherwise provided for in this section, 3 cents per pound; cork insulation, wholly or in chief value of granulated cork, in slabs, boards, planks, or molded forms, cent per pound; cork paper, 35 per centum ad valorem; manufactures wholly or in chief value of cork or of cork bark, or of artificial cork or bark substitutes, granulated or ground cork, not specially provided for in this section, 30 per cent ad valorem. 464. Cork wood, or cork bark, unmanufactured, and cork waste, shavings, and cork refuse of all kinds. Free.

DESCRIPTION AND USES.

Cork, as its name implies, is the cortex or bark of a species of evergreen oak indigenous to southern Europe and northern Africa. The trees attain a height of 20 to 40 feet, live to great age (300 to 400 years), and average approximately 12 inches in diameter. Specimens occasionally are found as much as 12 feet in circumference. The bark is silvery gray and is quite unlike the bark of other oaks in texture. Its thickness and quality vary with the soil and climatic conditions. If the ground is rich and damp the bark is

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thick and generally open and poor in quality. The best cork comes from the mountainous districts where the soil is thin and the rainfall not very abundant.

It is stripped from the tree during July and August, at intervals of about nine years. Longitudinal and transverse incisions are made to the proper depth and the bark then pried off in slabs, great care being taken not to injure the tree. Commercial bark varies from one-half inch to 2 inches in thickness, occasionally 21⁄2 inches. It is taken from both the trunk and limbs, the thicker bark coming from the trunk. Also young vigorous trees furnish thicker bark than older ones. The average yield per tree is 45 pounds.

Practically the entire world's production is obtained from Portugal, Spain, France, Italy, Tunis, Algeria, and Morocco, Portugal producing about one-third. From Korea a species of cork is also obtained which possesses some but not all the qualities of that from the Mediterranean countries.

The industrial uses of cork are many, the various articles into which it is manufactured being too numerous to enumerate. Its best known field of utility is in the manufacture of cork stoppers, and cork disks. The latter are used as washers in the crimped metallic stopper known as crown" corks now almost universally used on containers for mineral waters, ginger ale, beer and other beverages. Other uses for which it is very desirable because of its qualities of lightness, elasticity, compressibility and impermeability to water are floats of nets, life preservers, swimming belts, etc.; smokers mouthpieces and cigarette tips; insulation for refrigerators and pipes; in doors and telephone cells to deaden sound; toys; insoles; polishing wheels and rubber for burnishing glass and gold; displaying cutlery; in balls, toys and games, and many other articles, either made from the cork in its natural state or from the waste or shavings as a composition.

In powdered form cork waste is used in making linoleum and other floor coverings, this use being specially provided for in the tariff (par. 276).

Cork bark, cut into squares, cubes or quarters, is a preliminary step in the cutting of corks, generally those made by handwork. Very small imports of it in this condition are made.

Substitutes. No altogether satisfactory cork substitute has been found, although the wood of some trees possessing a cellular sponginess, lightness, and elasticity has been substituted in many of its uses. One such, known as cordewood or alligator apple, grows in the West Indies. Rubber is used to a great extent for bottle stoppers, and many patent devices and compositions have been employed, but none are the equal of the cork stopper for general use.

DOMESTIC PRODUCTION.

Raw material.—No cork for industrial purposes is grown in the United States. The culture was attempted here as early as 1858, but was not vigorously prosecuted. It is now being introduced experimentally at Chico, Calif., by the Bureau of Plant Industry, and in Florida, by the United States Forestry Service.

With relation to these experiments, the Bureau of Forestry in a report dated March 29, 1916, states:

The cork oak is adapted to growing in certain portions of this country, notably portions of California, Florida, and the Gulf States. It does not thrive in a climate where the minimum temperature goes below 21° F. and where the maximum exceeds 104° F. The cork oak requires a porous, fairly moist soil and an annual precipitation of at least 20 inches. In western Florida, on the Choctowhatchee division of the Florida national forest, some of the trees grown from seed sown in the spring of 1911 are now 10 feet tall and very thrifty. They are, however, on fairly good soil which was thoroughly plowed and which was formerly used as a garden patch. The very largest of the trees have received some fertilizers. At slightly higher and drier elevations in the sandhills the trees have not prospered, and it seems evident that a moist and somewhat richer soil than this pure sand is necessary for their satisfactory development.

Manufactures. Lacking a native supply, all the bark used in the domestic cork industry is imported. Domestic manufactures embrace practically all the products of cork, with the possible exception of cork paper. This was formerly produced here, but is now practically all imported. The chief products are cork stoppers (generally known as corks), disks and wafers used in the crown cork, and cork board and insulation from the waste or shavings.

Processes. Before shipping, the slabs as cut from the trees are dried for a few days and are then steamed or placed in boiling water. This process enables the useless outer coating to be scraped off, increases their bulk and elasticity, and removes the tannic acid. It is next scraped, by which process it loses about 20 per cent in weight, then cut into proper sized pieces for baling, and sorted into numerous grades of quality and thickness. After sorting it is baled, rendered compact under pressure, and each bale marked as to quality. Bottle corks. Corks are made both straight and tapered and in a great variety of sizes. The thickness of a piece of bark determines the maximum diameter of the stopper, as the cutting is done across the grain. The baled bark is first re-sorted, an average bale of 180 pounds being sorted into about 4 thicknesses of wood and 4 grades, or a total of 16 kinds of wood. The importance of sorting can not be overemphasized, since the whole problem of successful and economical manufacture centers about it. The wood is steamed in ovens for about 15 minutes to soften it for working, and then sliced into strips by a revolving disk. The width of these strips determines the length of the corks. The slices or strips are then taken to punching machines where the corks are cut out, either by automatic machines or by hand punches. The "punch" is a sharp revolving hollow cylinder of the required diameter. The hand. punches are more desirable for high-grade corks, as the workmen can avoid the defects in each piece of cork, whereas the automatic machines punch equal spaces in each strip, regardless of defects. For tapered corks a further step is required-placing the corks in slots which are pressed against a revolving disk at such an angle that one revolution of the cork against the disk gives the proper taper. The corks are then sorted, polished, and bleached.

As will be seen, a great deal of waste is incidental to the making of corks, and this is utilized in various ways for making articles of cork composition or for loose insulation.

Cork disks or wafers.-Cork disks or wafers, used primarily in crown corks, and to a small extent for other purposes, are made both from the natural cork and from cork shavings or waste, the domestic product being chiefly the latter. For composition disks

a good quality of waste is used. It is ground, and carefully cleaned by friction and air blast to remove all dust and defective cork wood, then mixed with a binder of rosin, glycerine, and other materials, compressed in tubes the desired diameter, and baked at low heat, great care being taken not to char the cork. The tube is then cooled and the composition as it is pressed out cut into disks about an eighth of an inch thick by automatic machinery. The disks are then sorted and packed.

The natural cork disks are made in an entirely different manner. Good quality bark is cut into strips about twice the desired diameter of the disks and the rough outer bark ripped off. It is then split into narrow strips of the finished thickness and the disks punched out by machinery.

Cork insulation board. This also is a product manufactured from the waste incurred in the manufacture of corks and other articles cut from natural bark. The waste is ground or macerated and sifted through screens of different sized meshes. The larger granules are used for insulation board and the smaller, some of which are further ground, used in the production of cork floor tiles, composition cork disks, and in powdered form for linoleum.

The ground cork is compressed in molds and baked at 400° F. for four or five hours. The pure ground cork only may be used, the natural gum or resin serving as a binder, or a foreign binder, such as glue, asphalt, pitch, or cement, may be used. The sheets are removed from the mold, trimmed, and cut into standard sizes, 1 foot by 3 feet, with thicknesses of 2, 3, or 4 inches.

Sorting. One of the most important as well as expensive single items in the industry is that of sorting, both of the bark and of the finished articles. The bark is very carefully sorted to obtain the better grades for the higher quality corks, but even so, it is not possible to obtain a finished article of uniform quality. Therefore, in order to make a specified number of a particular quality of corks, it is necessary to manufacture a great many of other qualities, which necessitates the careful sorting of the finished products. The same applies to cork paper and other products.

Cork paper. For cork paper the finest quality of bark is selected, cut into blocks 3 by 6 inches, and the rough front and back faces ripped off. The block is then glued fast to a steel plate and placed in the cutting machine, which cuts the bark into sheets about of an inch thick. The sheets are then carefully stacked, ground to uniform sizes, and very carefully sorted into grades. Practically all cork paper produced is used for cigarette tips, and very little, if any, is now made in this country. The cost to the cigarette manufacture is from 9 to 20 cents per thousand tips.

Organization. The census of manufactures for 1914 gives the value of cork cutting products as $7,875,000, as compared with $5,940,000 in 1909, and $4,491,000 in 1904. The average number of wage earners was 3,454, of whom 2,051 were male and 1,345 female, a total of 155 being under 16 years of age; 52 establishments. were engaged in the industry, with capitalization of $7,602,000 and wages of $1,582,000. New York, New Jersey, and Pennsylvania are the leading States.

Hand cutting has entirely disappeared here, automatic machinery or combined hand and machine work having entirely supplanted it.

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Female help is being largely employed on the automatic machines where great skill is not required. Some of the work, however, requires skilled labor, such as the punching of the higher-grade corks, where male operatives feed the punches by hand in order to utilize the best portions of the bark. Practically all the machinery is of American origin and make, but has been adopted by the cork makers of foreign countries.

Some of the American firms also maintain factories in Spain, importing their products to this country.

EXPORTS.

Exports of domestic manufactures have shown a steady increase except in 1915, when they dropped to $211,765 from $462,199 for 1914. They reached $1,081,537 in 1919, and $2,002,174 for the calendar year 1920. Canada, Mexico, Cuba, and Panama are the chief buyers. Japan and the countries of South America are also important markets. Statistics are not available as to the specific articles which compose these exports.

FOREIGN PRODUCTION.

The area over which cork culture extends is approximately as follows: Portugal, 1,482,000 acres; France and her African possessions, 1,633,331 acres, of which 1,052,556 are in Algeria and 202,622 in Tunis; Spain, 741,300 acres. Italy was formerly a large grower of cork, but the production has greatly decreased through lack of culture and destruction of the cork-oak forests.

Portugal is the leading producer, growing about one-third of the world's supply. Practically all of this is exported unmanufactured. Spain is second in production, but, unlike Portugal, exports only a small amount of the unmanufactured bark-about 18 per cent of production, as compared with exports of about 70 per cent of her manufactures of cork. She is also a large importer of unmanufactured bark from Algeria, France, Morocco, and Portugal. The industry affords employment to about 30,000 people, and modern machinery is used to a very large extent. A number of factories are maintained in Spain by foreign corporations for the production of articles chiefly for export to their home countries. In 1919 Spain imported 3,813,409 pounds of crude cork and produced 176,000,000 pounds of manufactured products, of which 102,197,609 pounds, valued at $7,514,579, was exported. The chief countries of export are the United States, France, and Argentina. England and France are also large manufacturers of cork products, England being a large exporter of crown corks.

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IMPORTS.

Cork bark and waste are imported principally from Portugal, that country furnishing more than half the total. Practically all the remainder comes from France, Spain, and French Africa. Imports from France consist principally of waste. In 1920 the total imports of unmanufactured cork were 223,477,340 pounds, valued at $6,338,330, of which 169,549,364 pounds, with a value of $3,741,730,

1 Commerce Reports, No. 302, Dec. 24, 1920.