paint is much in favor as the first or priming coat to be applied to iron and steel. Enormous quantities of these paints are used each

year.

Bituminous paints, which are composed of coal tar dissolved in petroleum light oils and benzol, are used for a protective coating on cement, water pipes, and carriers which are to be placed beneath the surface of the ground. Utah gilsonite (asphalt) is dissolved in turpentine or in drying oils by the aid of heat and reduced with thinners for high grade bituminous coatings. These products are also used as baking japans on hardware and other metal manufactures. These coatings are more logically classed as varnishes as they do not contain a pigment.

Marine or antifouling paints are used to paint the bottom of ships to protect them from barnacles, which greatly reduce the speed of ships when they become attached to them. They are of two classes one depends on using a grease or soap in the paint so that the weight of the barnacles causes them to drop off, and another depends on poisonous ingredients to kill the barnacle. This latter class has become the more important. They usually contain mercuric oxide, copper cyanide, or copper scale (oxide) as the poisonous ingredient. Zinc oxide and iron oxides generally constitute the pigment part and are mixed with a rapid drying varnish, usually shellac. Pine-tar oil and turpentine are also used to some extent.

Floor paints are a type of enamel paints designed to resist abrasion and for application on surfaces subject to constant wear. Such paints are made upon a zinc, lead, and inert pigment base which is ground in linseed oil and then mixed with a kauri gum varnish and thinned with turpentine.

Water paints, such as calcimine, consist of gypsum or whiting as the inert base and often a considerable percentage of zinc oxide, lithopone, clay, or silica and are tinted with mineral oxides. These pigments are mixed with glue or casein as binding materials and are sold in powder form ready to be mixed with water and applied. Although these water paints are widely used because of their comparative cheapness they are not washable and are not as durable as oil paints.

Artists' paints and colors consist of various pigments ground in a special grade of drying oil, such as walnut oil, which drys to a transparent colorless film. These paints are usually put up in tubes for artists' use. They constitute a small part of the paint industry.

DOMESTIC PRODUCTION.

Size of the industry. The Census of Manufactures, 1914, shows that there were 585 establishments engaged in the manufacture of paint and pigments, with an output of $112,408,742. Of this production, about $73,000,000 was represented by paints, including those in paste form, mixed ready for use, and water paints. The production of paints mixed for use was 40,745,000 gallons valued at $41,500,000. Production and consumption. The domestic production of paints supplies practically the entire domestic consumption, as the value of imports in 1914 was less than 1 per cent of the value of the domestic output. Although statistics are not available, the United States is undoubtedly one of the leading producers of paints, as paint is used to a greater extent in this country than in any other civilized nation.

Exports. The exports of ready-mixed paints in 1913 and 1914 were about 900,000 gallons, valued at over $1,000,000. The exports of ready-mixed paints in 1914 were about 1.5 per cent of the domestic production. In 1915 they decreased to about 700,000 gallons, valued at $885,000, but then steadily increased to 2,262,000 gallons, valued at about $2,700,000, in the calendar year 1919. Cuba has taken between 25 and 35 per cent of the total exports of ready-mixed paints. Exports to European countries have been comparatively small. South and Central American and Oceanic countries have been the principal consumers. As a whole, exports of mixed paints have been diversified.

Process of manufacture.'-The materials required in the manufacture of paints are a pigment, drying oil, thinner, and a drier for quickdrying paints.

The white pigments used in paints are basic carbonate white lead, basic sulphate white lead, zinc oxide, leaded zinc, and lithopone. Inert fillers, such as barytes, china clay, silica, and asbestine, are used along with these pigments. The colored pigments consist of natural earth colors (ocher, umber, sienna, iron oxides) and chemical pigments, such as ferro-ferricyanide blues, chromates, color lakes. Linseed oil is the principal drying oil used and serves as the "vehicle" or pigment carrier. Other oils are used in conjunction with linseed or in place of it. Perilla oil has been used the most extensively.

The thinners used in paint are chiefly turpentine, high boiling point petroleum, benzine, and benzol. These thinners are used to reduce the paint to a suitable consistency for application.

Driers used in paints are oxides of lead and manganese added to hot linseed oil or resinates and oleates of lead and magnanese dissolved in benzine or other volatile solvent.

In the manufacture of paints the pigment is first mixed with oil in a rotary mixer or an edge runner. This mixture is then milled through revolving plates of dressed stone or steel and comes from the mill in the form of a smooth, heavy paste. The paste is stored in large tanks and removed as needed to smaller mixing tanks, where it is thinned with additional linseed oil, and thinners, driers, and tinting colors are added. After thorough mixing of the various ingredients the prepared paint is then packed in containers for shipment.

The paint factory is usually arranged so that the pigments are stored on the top floor and then work downward through the various manufacturing steps until the finished paint is packed on the lower floor for shipment. The liquids-drying oil, thinners, driers-are kept in large storage tanks in the basement of the building or outside, and transferred to the desired point through pipes by means of compressed air.

IMPORTS INTO THE UNITED STATES.

The combined imports of paints prior to the war were valued at between $500,000 and $650,000. In 1914 imports of paints were less than 1 per cent of the domestic output. During war years imports

Abstracted from article on "The manufacture and use of prepared paint products," by Henry A. Gardner, in Roger's Manual of Industrial Chemistry.

declined to $135,000 in 1918. During the 1919 calendar year they were valued at $218,117.

The bulk of the imported paint has come in under the general provision "all other paints, colors, pigments, stains, n. s. p. f." Imports under this classification prior to 1914 were valued at between $400,000 and $570,000. They declined to $43,523 in 1918, and then increased slightly to $109,492 in 1919 (calendar year).

Imports of enamel paints have been small and sporadic; the maximum import was valued at $17,000 in 1914.

Imports of artists' paints or colors showed a steady growth prior to the war to over $200,000 in 1914. They then decreased to $91,220 in 1918. During the 1919 calendar year imports were valued at $103,000.

TARIFF HISTORY.

Provision was made in the act of 1890 for "artists' colors of all kinds, in tubes or otherwise," at 25 per cent ad valorem, and for "artists' water-color paints," dutiable at 30 per cent ad valorem. The act of 1894 provided for "all colors in tubes," dutiable at 25 per cent ad valorem. In the act of 1897 the provision was changed to "all paints, colors, and pigments, commonly known as artists' paints or colors, whether in tubes, pans, cakes, or other forms,' and a duty of 30 per cent was imposed. This provision was repeated in the acts of 1909 and 1913 with a duty at 30 per cent and 20 per cent, respectively.

In the act of 1909 "enamel paints made with varnish" were made dutiable at 35 per cent ad volorem. The act of 1913 reduced the duty on enamel paints to 15 per cent ad valorem. All paints and colors n. s. p. f. were dutiable at 25 per cent ad valorem under the acts of 1883, 1890, and 1894; at 30 per cent under the acts of 1897 and 1909; and at 15 per cent ad valorem under the act of 1913.

Paints, pigments, colors, and varnishes-Imports by countries (fiscal years).

All other paints, colors, pigments, stains, smalts and frostings, crude dry, mixed or ground with water or oil or other solutions, n. s. p. f.—Imports for consumption-Revenue.

1 From July 1 to Oct. 3, 1913, under the act of 1909 listed as "Enamel paint made with varnish." 2 From Oct. 4, 1913, to June 30, 1914.

Artists' paints or colors, etc.-Imports for consumption-Revenue.

Combined imports of enamel paints, artists' paints or colors, and all other paints, colors, pigments, stains, smalts, and frostings, n. s. p. f.-Imports for consumption-Revenue.

Paints, pigments, colors, and varnishes: Ready-mixed paints 1—Domestic exports (fiscal