Crude cottonseed oil is purified by heating with caustic soda and by further treatment with fuller's earth. The clear oil when cooled to 12° below zero, Centigrade, separates into a part used in making oleomargarine, and a clear oil which is used in large quantities as a salad oil and for mixing with olive oil. The impure residue removed by treat ment with caustic soda is used by soap-makers. Cottonseed oil occurs very largely in various arti cles used in cooking as substitutes for lard. [See Cotton.] In both cottonseed- and flaxseed-oil production, the United States ranks as an exporter except under special conditions, when the demand for flax seed may result in importation from Argentina and from British India.
In the preparation of these oils, the residual "cake" is a valuable by-product, which is also an article of export as well as of home consumption.
Flax (Linum usitatissineum, Linn.). Linaceo.
In the case of flax seed the crop of the country seems to lie betwem 20,000,000 and 28,000,000 bushels per annum, grown in large part in Min nesota, North and South Dakota. There is a minor production in Iowa, Kansas, Missouri and Idaho. The important centers of the trade are at Chi cago, Minneapolis and Duluth, where store-houses and crushers provide accommodations for the ship per or for the manufacturer of linseed oil. The chief use of linseed oil is found in the making of paints. The desired pigments, finely ground, arc mixed with the oil and applied to the surface to be covered. The oil is quickly acted on by the atmos phere in such a way as to harden it, and is classed for this reason as a drying oil. Linseed oil is put on the market as raw oil or as boiled oil. The cake left after the expression of the oil is a valuable stock-feed, and, as such, forms an important article of commerce. [See Flax.] Niger (Guizotia oleifera, Cass.). Composite. Fig. 726.
Niger seed is derived from an erect annual plant reaching a height of about three feet. It has opposite, lanceolate-oblong, serrated leaves, numer ous bright yellow flowers one to one and one-half inches in diameter, borne on elongated stems. The seed is formed by the inconspicuous disc flowers.
This plant, native of Abyssinia, is cultivated in Mysore, India, and to a lesser degree in Germany and the West Indies, principally for the pale yellow fatty oil expressed from the seed. The yield is about 35 to 40 per cent. The oil is used for illumination, and in making soap. The higher grades are also
used for food purposes. It has a chracteristic pleasant aromatic odor. The seed is used also in bird-seed mixtures. It reaches the European mar ket by way of London and Hamburg, but is not imported in the United States. Its experimental culture here has been recommended.
Olive oil (Olea Euroyea, Linn.). Oleacece.
Olive-growing in the United States is practically confined to California and Arizona. The total crop in 1899, according to the United States Census, was about 5,000,000 pounds. The fruit is in part used for pickling and in part for the production of olive oil. The oil is obtained by expressing.
The demand for olive oil is large and is in part supplied from foreign sources, notably Italy and France. In 1904, the total importation was about 1,700,000 gallons. This oil does not readily become rancid. The better grades of the oil are used as salad oil, the poorer for soap-making and in processes connected with the manufacture of tobacco.
Peanut oil (Arachis hypoyea, Linn.). Legunzinosae.
Peanut-culture in the United States is found chiefly in the South, Virginia, North Carolina, Georgia, Alabama, Florida and Tennessee being the largest producers in the order named. The total crop for the United States in 1899 was about 12,000,000 bushels, valued at sixty-one cents per bushel. In 1904, the United States imported pea nuts, shelled and unshelled, to a value of about $148,000. The peanut crop has increased during the last decade to a remarkable degree, due doubt less to the increased use. Aside from its use in a whole roasted condition, the fruit is the source of an oil which is expressed from it.
Peanut oil when expressed cold is pale in color and may be used as a salad oil, although it becomes rancid more readily than olive oil. It is used as an adulterant for olive oil, also in making butterine. The lower grades are used in soap-making. Sar dines are frequently preserved in peanut oil. The "cake" remaining after expression of the oil is used sometimes as a stock-feed. [See Peanut.] Sesame (Sesamuin Indium, Linn.). Pedaliacae.
Sesame (bene or til) is an annual herbaceous plant growing two and one-half to seven feet tall. The leaves are variable, three to five inches long, oblong or lanceolate, the lower often three-lobed or three-parted ; the corolla is pale rose or white, one inch long, and tubular. The pods are about three inches long.