whale oil, oil extracted from the blubber and other parts of certain species of whales. It varies in composition, color, and the degree of fishy odor according to the method and extent of refining. Formerly widely used as an illuminant, it was superseded by petroleum products. It is used today in soapmaking, as a leather dressing, and as a lubricant. Some is hydrogenated to form edible fats. The term is also sometimes used to include sperm oil.

tung oil, oil obtained from the seeds of a tropical tree, the tung tree (Aleurites fordii) of the spurge family, and from seeds of some related species, all from Indomalesia or W Pacifica. It is known also as China wood oil and nut oil. The poisonous seeds found in the heart of the tung fruit (which is the size of a small apple) contain more than 50% tung oil, readily obtained when the seeds are heated, ground, and pressed. The oil is amber-colored and contains a high proportion of eleostearic acid. Because of its wide use as a dryer in varnishes and paints, it has great commercial importance. While the bulk of the product is utilized by the paint and varnish industry, tung oil has additional uses, e.g., as a component of insulating compounds and in the manufacture of linoleum and oilcloth. China was long the chief producer of the oil, but the tree has been introduced in other areas as well. The U.S. Dept. of Agriculture experimented with tung tree growing early in the 20th cent., and afterward encouraged Southern farmers to cultivate it. In recent years, an increasing portion of the commercial supply has been obtained from trees grown in the United States, particularly in the South.

sperm oil, liquid wax obtained from the sperm whale, or cachalot, and related marine mammals. It flows readily, is clear, and varies in color from pale yellow to brownish yellow. Chemically it is not a true oil. It is secured from the blubber and from a huge cavity in the whale's head (this oil cavity helps the whale keep part of his head above water for breathing). A solid wax, spermaceti, is extracted from the oil by filtration and treatment with potassium hydroxide. The oil is an excellent lubricant, especially for watches and other delicate instruments, and is used as a dressing for leather, to protect plants from insects, in tempering steel, and in making soap.

palm oil: see palm.

olive oil, pale yellow to greenish oil obtained from the pulp of olives by separating the liquids from solids. Olive oil was used in the ancient world for lighting, in the preparation of food, and as an anointing oil for both ritual and cosmetic purposes. It is produced mainly in Algeria, Greece, Italy, Morocco, Portugal, Spain, Tunisia, and Turkey. The characteristics of the oil vary with the climate, cultivation, and variety of olive. Olive oil is one of the most digestible of the edible oils. To make the finest, or extra-virgin olive oil, the fruit is gathered when fully ripened, ground to a paste under granite or steel millstones, layered over straw mats, and pressed in a hydraulic press. Today, most olive oil is produced by just one pressing. The resulting oil is separated from the juice by settling or by centrifuge and then filtered. Olive oil of good quality is ready to use, without further refinement. Although olive oil occupies a relatively minor place in world food consumption, it has, in recent years, become a stronger export item, and a succession of international agreements have been signed since 1959 to protect its market. Olive oil is now the third best-selling cooking oil in the United States. Both gourmets and health professionals have praised its qualities, thereby contributing to its growing popularity. Olive oil is a monounsaturated fat and, unlike butter, lard, and other fats, contains a large proportion of easily digested fats and no cholesterol. Olive oil is also a good source of vitamin E, which is thought to help protect humans against cancer and heart disease. The principal fat in the diet of countries where it has long been cultivated, olive oil is often used in place of cream and butter and as a cooking fat and salad oil. Although olive oil is chiefly used as a food or in food preservation, it is also used in soaps, certain pharmaceuticals, and cosmetics.

oil spill: see water pollution.

oil of wintergreen: see salicylic acid.

oil of vitriol: see sulfuric acid.

oil of bitter almond: see benzaldehyde.

oil industry, the business of discovering oil (petroleum), extracting it from the ground, refining it into a variety of products, and distributing it to the public. The development of the oil industry in the 19th and 20th cent. provided a source of energy that now supplies about two fifths of the world's energy needs as well as a raw material that chemical and petroleum industries refine into a number of essential chemicals and industrial products.

Early History

Petroleum seeping out of underground reservoirs has been collected and used for light throughout recorded history. In the 4th cent. A.D. the Chinese drilled for oil and natural gas, but in the 1850s, oil was still being recovered by skimming it off the tops of ponds. As whale oil became less abundant, producers looked for new ways to extract oil. Edwin Drake dug the first modern oil well in Titusville, Pa, hitting oil at 69.5 ft (21.2 m), touching off an oil rush in the area. (Most modern wells go down over 4,700 ft (1,432 m).) In 1861 the first oil refinery was set up.

Development of the Modern Industry

During the late 19th cent., many of the modern oil companies were created: John D. Rockefeller invested in a Cleveland oil refinery during the Civil War and in 1870 created Standard Oil, which refined about 95% of the United States' oil in 1880. In 1911, Standard Oil was declared an illegal monopoly and split into 34 companies, including Esso (renamed Exxon in 1972), Mobil, Chevron, Atlantic Richfield (later ARCO), and Amoco. Texaco (founded in 1902), Shell (1907), and British Petroleum (1909) were also established in this period. As the auto industry vastly increased the demand for gasoline refined from oil, oil companies expanded their search for new reserves. In the 1930s oil companies began exploiting a huge E Texas oil field that would eventually produce 4 billion barrels of oil. Chevron, Texaco, Exxon, and Mobil expanded their reserves by purchasing the rights to the extensive Saudi Arabian oil fields for only $50,000. In 1946 oil replaced coal as the world's most popular energy source.

Late-Twentieth-Century and Early-Twenty-First-Century Developments

In 1960 the Organization of Petroleum Exporting Countries (OPEC) was formed. Over the next decade, OPEC required that the major oil companies provide them with a larger percentage of the profits from their fields. After the oil embargo in 1973, OPEC boosted prices to $35 a barrel in 1981. The resulting energy crisis forced many developing countries to pay more for energy, negatively affecting Third World debt; industrialized countries implemented new measures to conserve and develop new sources of energy. Some new oil fields in Alaska and the North Sea were developed, boosting the world's oil reserves from 645.8 billion barrels in 1978 to 1,052.9 billion barrels in 1998. With an abundant supply, oil prices dropped and stayed low through the 1990s, until 1999 when OPEC announced that it would cut production in order to increase oil prices worldwide. With the help of non-OPEC oil-producing nations, the organization was subsequently generally able to maintain prices between $20 and $30 a barrel, and world events and demand have driven prices significantly higher.

Economies dependent on oil production remain subject to the gyrations of the market. The collapse of oil prices in the mid-1980s ruined many independent refiners and helped produce a recession in such states as Texas; it also hurt Mexico, Venezuela, and other oil-producing nations. In contrast, the rise in oil prices since 1999 has been responsible for economic growth in Russia, Venezuela, and other oil producers. Improved recovery methods combined with higher prices that justify more expensive extraction costs have rejuvenated production in some older oil fields, increased the estimates of reserves in existing fields, and made feasible the exploitation of deposits once considered uneconomical.

Many oil-producing nations in the Middle East and Latin America have set up their own refining operations since the 1970s, and state-owned oil companies in OPEC countries are now among the world's largest. Many large oil companies have diversified into chemicals, and oil prices are increasingly set on commodity trading exchanges such as the New York Mercantile Exchange. Beginning in the late 1990s, the industry saw increased consolidation as already large oil companies merged with each other, including Exxon (the largest U.S. oil company) with Mobil (the second largest; forming ExxonMobil), Chevron with Texaco and Unocal as Chevron, British Petroleum with Amoco and ARCO as BP, and Conoco with Phillips Petroleum as ConocoPhillips.

oil gas, any of a group of fuel gases produced from oil by exposing it to high temperatures. High-Btu oil gas is so called because of its high heating value; it is often used to supplement natural gas during periods of high demand. Refinery oil gases are produced as byproducts during normal heat treatment in oil refining. Their chief use is in the heating of refinery equipment. Typically, oil gas consists of methane, ethane, propane, butane, and some of their derivatives.

oil beetle: see blister beetle.

mineral oil: see petrolatum.

linseed oil, amber-colored, fatty oil extracted from the cotyledons and inner coats of the linseed. The raw oil extracted from the seeds by hydraulic pressure is pale in color and practically without taste or odor. When boiled or extracted by application of heat and pressure, it is darker and has a bitter taste and an unpleasant odor. Linseed oil has long been used as a drying oil in paints and varnish. It is also used in making linoleum, oilcloth, and certain inks.

fusel oil, oily, colorless liquid with a disagreeable odor and taste. It is a mixture of alcohols (largely amyl alcohols) and fatty acids, formed during the alcoholic fermentation of organic materials. After imperfect distillation of these fermentation products it becomes an impurity in the distilled liquor. Fusel oil is used as a solvent in the manufacture of certain lacquers and enamels (it dissolves nitrocellulose). It has a detrimental effect on the human system.

drying oil, any of several natural oils which, when exposed to the air, oxidize to form a tough, elastic film. The common drying oils are cottonseed oil (see cotton), corn oil, soybean oil, tung oil, and linseed oil; the first three oils mentioned are more properly called semidrying oils. Linseed oil is the most widely used. Drying oils are used mainly in paints, varnishes, lacquers, and printer's ink. Use is recorded as early as A.D. 200 of boiled linseed oil, which dries faster than raw oil. Tung oil is imported from China, and linseed oil mainly from Argentina. Drying oils have also been prepared from various nondrying fish oils (e.g., sardine and herring oils) and from whale oil.

crude oil: see petroleum.

cottonseed oil: see cotton.

cod-liver oil, yellowish oil obtained from the liver of the codfish. The oil is rich in vitamin A and vitamin D (calciferol). It was long used as a preventive and cure for rickets in Baltic and Scandinavian countries, where fish is a dietary staple. However, it was not until the 1920s that doctors in the U.S. finally recognized its therapeutic usefulness. More palatable synthetic vitamins have largely replaced cod-liver oil as dietary supplements, and almost all the milk sold in the United States and Europe now contains added vitamins A and D. See vitamin.

castor oil, yellowish oil obtained from the seed of the castor bean. The oil content of the seeds varies from about 20% to 50%. After the hulls are removed the seeds are cold-pressed. Medicinal castor oil is prepared from the yield of the first pressing; this is used as a purgative and laxative. Oil from the second pressing is used as a lubricant for machinery, as a softening agent in making artificial leather, in the dressing of genuine leather, in brake fluids, and in paints and plastic materials. The residue can be used as fertilizer and (after the poisonous substance, ricin, is removed) as cattle feed. Other products having similar properties and uses have been gradually replacing castor oil.

Oil City, city (1990 pop. 11,949), Venango co., NW Pa., on the Allegheny River; inc. 1871. The city was founded after Edwin L. Drake struck (1859) oil nearby in Titusville. It was a refining and shipping center for the state's oil industry and a producer of oil-field equipment until the last of the oil companies left the city in the mid-1990s. Manufactures include continuous-casting equipment, plastics, aluminum castings, motor oil, machinery, antioxidants, and steel tubing.

Any of a class of highly volatile (readily evaporating) organic compounds found in plants and usually named for them (e.g., rose oil, peppermint oil). They have been known and traded since ancient times. Many essential oils contain isoprenoids. Some, such as oil of wintergreen (methyl salicylate) and orange oil (math.d-limonene), have one predominant component, but most have dozens or hundreds. Trace components impart an oil's characteristic odour, which synthetic or blended oils can rarely duplicate. Essential oils have three primary commercial uses: as odorants in perfumes, soaps, detergents, and other products; as flavours in baked goods, candies, soft drinks, and many other foods; and as pharmaceuticals, in dental products and many medicines (see aromatherapy).

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Synthetic crude oil that is extracted from oil shale by pyrolysis, or destructive distillation. The oil obtained from oil shale cannot be refined by the methods that have been developed for crude oil, however, because shale oil is low in hydrogen and contains large amounts of nitrogen and sulfur compounds. To be made usable, shale oil must be hydrogenated and then chemically treated to remove the nitrogen and sulfur, a process too expensive to make shale oil commercially competitive with crude oil. Seealso kerogen, petroleum.

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or kerosine

Organic compound, a clear, oily, highly flammable liquid with a strong odour, distilled from petroleum (10–25percnt of total volume). It is a mixture of about 10 different types of fairly simple hydrocarbons, depending on its source. It is less volatile than gasoline, boiling at 285–610 °F (140–320 °C). It is burned in lamps, heaters, and furnaces and is used as a fuel or fuel component for diesel and tractor engines, jet engines, and rockets and as a solvent for greases and insecticides.

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First method for direct measurement of the electric charge of a single electron, originally performed in 1909 by Robert Millikan. He used a microscope to measure the rate of descent of tiny oil droplets directed through the top of a box. By halting the descent of droplets carrying their own electric charge by means of precisely adjusting the voltage between the box's metal top and bottom, he discovered that the electric charges on the drops were all whole-number multiples of a lowest value, the elementary electric charge itself, and thus that electric charge exists in basic natural units.

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Any fine-grained sedimentary rock that contains solid organic matter (kerogen) and yields significant quantities of oil when heated. This shale oil is a potentially valuable fossil fuel, but the present methods of mining and refining it are expensive, damage the land, pollute the water, and produce carcinogenic wastes. Thus, oil shale will probably not be exploited on a wide scale until other petroleum resources have been nearly depleted. Estonia, China, and Brazil have facilities for producing relatively limited quantities, and the U.S. government operates an experimental plant in Colorado.

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or bituminous sand

Deposit of loose sand or partially consolidated sandstone that is saturated with highly viscous bitumen. Oil recovered from tar sands, commonly referred to as synthetic crude, is a potentially significant form of fossil fuel. The largest known deposits of tar sands occur in Canada's Athabasca River valley, where commercial projects for synthetic oil production from tar sands are being carried out.

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Painting in oil colours, a medium consisting of pigments suspended in drying oils. Oil paint enables both fusion of tones and crisp effects and is unsurpassed for textural variation. The standard consistency of oil paint is a smooth, buttery paste. It is applied with brushes or a thin palette knife, usually onto a stretched linen canvas. Finished oil paintings are often coated with varnish. Oil as a painting medium is recorded as early as the 11th century, though the practice of easel painting with oil colours stems directly from 15th-century techniques of painting with tempera (see tempera painting). In the 16th century oil colour emerged as the basic painting material in Venice; it has been the most widespread medium for easel paintings ever since.

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or oil of vitriol

Dense, colourless, oily, corrosive liquid inorganic compound (H₂SO₄). A very strong acid, it forms ions of hydrogen or hydronium (H⁺ or H₃O⁺), hydrogen sulfate (HSO₄⁻), and sulfate (SO₄²⁻). It is also an oxidizing (see oxidation-reduction) and dehydrating agent and chars many organic materials. It is one of the most important industrial chemicals, used in various concentrations in manufacturing fertilizers, pigments, dyes, drugs, explosives, detergents, and inorganic salts and acids, in petroleum refining and metallurgical processes, and as the acid in lead-acid storage batteries. It is made industrially by dissolving sulfur trioxide (SO₃) in water, sometimes beyond the saturation point to make oleum (fuming sulfuric acid), used to make certain organic chemicals.

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Any greasy substance liquid at room temperature and insoluble in water. It may be a fixed (nonvolatile) oil, an essential oil, or a mineral oil (see petroleum). Fixed oils and fats (derived from animals and plants) have the same chemical composition—both are esters of glycerol and fatty acids. These oils have a variety of industrial and food uses. Linseed, tung, and other drying oils are highly unsaturated (see saturation); these and large quantities of soybean, sunflower, and safflower oils (also constituents of foods) are used in paints and varnishes. When exposed to air they absorb oxygen and polymerize (see polymerization), forming a tough coating. Some specialty oils and oil derivatives are also used in leather dressing and textile manufacture.

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Oil obtained primarily from the liver of the Atlantic cod and related fish. It is principally a mixture of the glycerides (see glycerol) of many fatty acids, but its minor constituents, the fat-soluble vitamin A and vitamin D, give it its importance. It was once used to treat and prevent rickets, but the widespread fortification of milk with vitamin D in the United States and Europe beginning in the 1930s eliminated rickets as a significant public health problem. It is still used as a remedy for joint pain caused by arthritis and as a preventive of cardiovascular disease, although these benefits have not been proven scientifically. It is also used in feeds for poultry and other animals.

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Large plant (Ricinus communis) of the spurge family, probably native to Africa and naturalized throughout the tropics. It is grown commercially for the pharmaceutical and industrial uses of its oil and for use in landscape gardening because of its handsome, giant, fanlike leaves. The bristly, spined, bronze-to-red clusters of fruits are attractive but are often removed before they mature because of the poison concentrated in their mottled, beanlike seeds. There are hundreds of natural forms and many horticultural varieties of this species.

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