hydraulis, earliest known mechanical pipe organ. It was invented in the 3rd century bc by Ctesibius of Alexandria, culminating prior attempts to apply a mechanical wind supply to a large set of panpipes. Its pipes stood on top of a wind chest that was connected to a conical wind reservoir. The

dipper, (genus Cinclus), any of five species of songbirds of the Cinclidae family (order Passeriformes) noted for insect hunting by walking underwater in rushing streams and named for their frequent body bobbing. Among the best-known species are the Eurasian, or white-throated, dipper (Cinclus

water parsnip, any of several aromatic herbs of the genus Sium, especially S. latifolium, belonging to the parsley family (Apiaceae), distributed throughout the Northern Hemisphere and Africa. They grow in moist areas, and some species are even partially submerged. All are perennial herbs with

hookah, apparatus used to heat and vaporize tobacco for inhalation. The word hookah is derived from the Hindustani huqqa and the Arabic huqqah, meaning “vase” or “vessel.” The practice of smoking tobacco from a hookah likely originated in India or the Middle East. Today it is used worldwide and is

water plantain, (genus Alisma), any freshwater perennial herb of the genus Alisma (family Alismataceae), commonly found in lakes, ponds, and ditches. The 9 to 11 species of water plantains are primarily distributed throughout the Northern Hemisphere, 3 being native to North America. Water plantains

Alismataceae, the water plantain family of 113 species of freshwater flowering plants belonging to the order Alismatales and including 17 genera, the most common of which are Alisma (water plantain), Echinodorus (burhead), and Sagittaria (arrowhead). Most members of the family are native to the

Alismatales, arrowhead and pondweed order of nearly 4,800 species and 166 genera of flowering plants, belonging to the monocotyledon (monocot) group, whose species have a single seed leaf. The order contains 14 families that are broadly distributed throughout temperate and tropical regions with

Ceratophyllales: …unusual in that they have underwater pollination. When the male flowers are mature, the individual anthers break off and settle through the water until they reach a groove near the stigma of a female flower, leading to pollination.

water pollution, the release of substances into subsurface groundwater or into lakes, streams, rivers, estuaries, and oceans to the point that the substances interfere with beneficial use of the water or with the natural functioning of ecosystems. In addition to the release of substances, such as

water polo, sport played in a swimming pool by teams of seven with a buoyant ball resembling an association football (soccer ball). The game was originally called “football-in-the-water,” and indeed it is more like association football and basketball than polo, the name of the sport coming from an

Hydrocleys: The water poppy (Hydrocleys nymphoides), with yellow flowers about 5 cm (2 inches) across, is the only cultivated species and is often grown in ponds and aquariums.

water opossum, (Chironectes minimus), a semiaquatic, web-footed marsupial (family Didelphidae, subfamily Didelphinae) found along tropical rivers, streams, and lakes from Mexico to Argentina. Adults average 70 cm (28 inches) in total length and weigh up to 790 grams (1.7 pounds). A pouch is present

waterpower, power produced by a stream of water as it turns a wheel or similar device. The waterwheel was probably invented in the 1st century bce, and it was widely used throughout the Middle Ages and into modern times for grinding grain, operating bellows for furnaces, and other purposes. The

cooling system: …from the engine; (3) a water pump, usually of the centrifugal type, to circulate the liquid through the system; (4) a thermostat to control temperature by varying the amount of liquid going to the radiator; and (5) a fan to draw fresh air through the radiator.

water purification, process by which undesired chemical compounds, organic and inorganic materials, and biological contaminants are removed from water. That process also includes distillation (the conversion of a liquid into vapour to condense it back to liquid form) and deionization (ion removal

water rail, (Rallus aquaticus), slender marsh bird of the family Rallidae (order Gruiformes), native to most of Europe and Asia. Its length is about 28 cm (11 inches), and it has a moderately long beak. The sides of the bird have black and white bands. The name water rail also is used as a general

water rat, any of 18 species of amphibious carnivorous rodents. They exhibit many adaptations associated with hunting in water for food and burrowing along streams, rivers, and lakes. The eyes are small, the nostrils can be closed to keep water out, and the external portion of the ears is either

reed: …common, or water, reed (Phragmites australis) occurs along the margins of lakes, fens, marshes, and streams from the Arctic to the tropics. It is a broad-leafed grass, about 1.5 to 5 metres (5 to 16.5 feet) tall, with feathery flower clusters and stiff, smooth stems. Other plants of the…

fat and oil processing: Water refining: Water refining, usually called degumming, consists of treating the natural oil with a small amount of water, followed by centrifugal separation. The process is applied to many oils that contain phospholipids in significant amounts. Since the separated phospholipids are rather waxy or gummy solids, the term degumming was quite…

water resource, any of the entire range of natural waters that occur on the Earth, regardless of their state (i.e., vapour, liquid, or solid) and that are of potential use to humans. Of these, the resources most available for use are the waters of the oceans, rivers, and lakes; other available

South Dakota: South Dakota in the 21st century: The Water Resources Development Act of 1999 initiated the return of some of the areas along the Missouri River reservoirs to the tribes, but the final compensation amount for damage awarded to the Sioux has not been determined. The Missouri River Protection and Improvement Act was…

retting: In water retting, the most widely practiced method, bundles of stalks are submerged in water. The water, penetrating to the central stalk portion, swells the inner cells, bursting the outermost layer, thus increasing absorption of both moisture and decay-producing bacteria. Retting time must be carefully judged;…

wild rice, (genus Zizania), genus of four species of coarse grasses of the family Poaceae, the grain of which is sometimes grown as a delicacy. Despite their name, the plants are not related to true rice (Oryza sativa). Wild rice grows naturally in shallow freshwater marshes and along the shores of

cordierite: …Sri Lanka have been called water sapphires. Synthetic magnesium cordierite has a low thermal expansion and is used as a semirefractory material because of its resistance to thermal shock.

water scarcity, insufficient freshwater resources to meet the human and environmental demands of a given area. Water scarcity is inextricably linked to human rights, and sufficient access to safe drinking water is a priority for global development. However, given the challenges of population

Water scarcity results from insufficient available freshwater resources to meet the human and environmental demands of a given area. Spotlight, water, drought, global warming, climate change, population growth, conservation, water shortage Types of water scarcity include economic and physical or

water scavenger beetle, any of the approximately 3,200 species of the predominately aquatic insect superfamily Hydrophiloidea (order Coleoptera). These beetles are found swimming in marshy freshwater ponds throughout the world, especially in warm regions. Water scavenger beetles have smooth, oval,

water scorpion, any of the approximately 150 species of aquatic invertebrates of the family Nepidae (order Hemiptera). The water scorpion resembles a land scorpion in certain ways: it has scythelike front legs adapted for seizing prey and a long, thin, whiplike structure at its posterior end. This

Archimedes screw, machine for raising water, allegedly invented by the ancient Greek scientist Archimedes for removing water from the hold of a large ship. One form consists of a circular pipe enclosing a helix and inclined at an angle of about 45 degrees to the horizontal with its lower end dipped

Southeast Asian arts: Burma: …of dramatic verse, and his Water Seller is noted for its comparatively realistic treatment of court life.

water shield, (Brasenia schreberi), small purple-flowered aquatic plant of the fanwort family (Cabombaceae), found in northern ponds and still waters throughout the world, except in Europe. “Water shield” also refers to fanwort (Cabomba). Each oval, floating leaf of water shield is 5 to 10

fanwort, any of about seven species of aquatic flowering plants constituting the genus Cabomba, of the fanwort or water-shield family (Cabombaceae), native to the New World tropics and subtropics. Water shield is also the more commonly used name for Brasenia, the only other genus of the family. The

water shrew, any of 12 species of amphibious shrews that have a broad, fleshy muzzle, large chest, and long hind legs and digits. Most water shrews live in montane habitats and forage in clear, cold streams and small rivers. They use all four feet to swim, but most of the propulsive force comes

waterskiing, planing over the surface of the water on broad skilike runners while being towed by a motorboat moving at least 24 km/hr (15 mph). The skier holds onto a handle on a rope attached to the rear of the boat and leans slightly backward. Water skis are made of wood, aluminum, fibreglass, or

water snake, (subfamily Natricinae), any of about 200 species of semiaquatic snakes belonging to 38 genera (family Colubridae). Water snakes feed in or near water, and some leave aquatic environments only to bask in the sun or breed. Water snakes are characterized by stout bodies with strongly

Menyanthaceae: …for its fringed water lily, water snowflake, and floating heart, comprises submerged plants with buried rootstalks and floating leaves. Most species bear yellow or white flowers, and many are popular aquarium plants. The genera Liparophyllum and Nephrophyllidium both contain a single species, while Villarsia is larger but not well known.

water softener, device for removing calcium and magnesium from water; water so treated will not form insoluble scale in pipes and tanks and will not form a precipitate with soaps or interfere with other cleaners. Water softeners usually consist of zeolite or an ion-exchange resin (q.v.) in a tank

water softening, the process of removing the dissolved calcium and magnesium salts that cause hardness in water. Unlike hard water, softened water will not form insoluble scale or precipitates in pipes and tanks or interfere with cleaners such as soap. Water softening is thus indispensable in many

Hydrocharitaceae: The water soldier (Stratiotes aloides) bears rosettes of tough sharp-edged leaves that float in summer but sink and decay in the autumn. Vallisneria spiralis and V. americana are two eelgrasses commonly used as aquarium plants. Turtle grass (Thalassia species) is often washed ashore in such quantities…

alcohol: Physical properties of alcohols: …is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water. Methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and t-butyl alcohol are all miscible with water. Alcohols with higher molecular weights tend to be less water-soluble, because the…

fern: Annotated classification: …Azolla (about 6 species) and Salvinia (about 10 species), of floating aquatics, distributed nearly worldwide but most diverse in the tropics. Family Marsileaceae (clover ferns) Plants heterosporous; rhizomes long-creeping, slender, glabrous or hairy; leaves with 2 or 4 leaflets at the petiole tip or lacking a blade altogether, the venation…

curly-coated retriever: Developed in England from water spaniels and retrievers, it is one of the oldest retriever breeds, first exhibited in the United Kingdom in 1860. Its distinctive coat is either black or liver, covering the dog in short, tight curls except for its forehead, face, lower forelegs, and feet. It…

water spider, (Argyroneta aquatica), species of aquatic spider that is the only spider known to spend nearly its entire life underwater. The sole member of its genus, the water spider lives in a unique, underwater silk web, which resembles a kind of flexible diving bell. Water spiders are

water fern: richardii); and water sprite (C. thalictroides). The plants are widespread in tropical and warm temperate regions around the world, and several are cultivated as aquarium plants. Although water ferns sometimes root in mud, more frequently they float on the surface of shallow water in ditches, lakes, and…

mud plantain: Water star grass (H. dubia) is widely distributed throughout North America; it has yellow star-shaped flowers.

water strider, any insect of the family Gerridae (order Heteroptera), which numbers about 350 species. Water striders, often seen running or skating in groups over the surface of a pond or stream, are slender, dark coloured, and generally more than 5 mm (0.2 inch) long. With their short front legs

Doris Humphrey: Water Study (1928) incorporated her theory of fall and recovery and used only nonmusical rhythms (waves and natural human breath and pulse rhythms). Drama of Motion (1930) was themeless and also performed without music; it has been described as one of the first symphonic dances…

water supply, available water provided to fulfill a particular need. If the need is domestic, industrial, or agricultural, the water must fulfill both quality and quantity requirements. Water supplies can be obtained by numerous types of engineering projects, such as wells, dams, or reservoirs. See

water supply system, infrastructure for the collection, transmission, treatment, storage, and distribution of water for homes, commercial establishments, industry, and irrigation, as well as for such public needs as firefighting and street flushing. Of all municipal services, provision of potable

water table, upper level of an underground surface in which the soil or rocks are permanently saturated with water. The water table separates the groundwater zone that lies below it from the capillary fringe, or zone of aeration, that lies above it. The water table fluctuates both with the seasons

ice in lakes and rivers: Changes in temperature structure: …the temperature structure of lake water. In most lakes during the summer, a layer of warm water of lower density lies above colder water below. In late summer, as air temperatures fall, this top layer begins to cool. After it has cooled and has reached the same density as the…

ton: …specific commodities, such as the English water ton, used to measure petroleum products and equal to 224 British Imperial System gallons; the timber ton of 40 cubic feet; and the wheat ton of 20 U.S. bushels.

waterboarding, method of torture in which water is poured into the nose and mouth of a victim who lies on his back on an inclined platform, with his feet above his head. As the victim’s sinus cavities and mouth fill with water, his gag reflex causes him to expel air from his lungs, leaving him

How Do Water Towers Work?: Water towers provide essential equalizing pressure to a water supply system and store emergency water supply for times of water shortage. Tall and often located in an high area of a community, water towers work by utilizing the downward force of gravity exerted by water…

shipping, the transporting of goods and passengers by water. Described as the backbone of global trade, maritime shipping is responsible for the transport of the majority of raw materials, components, and finished products that drive the economy. Efficient and relatively low-cost, transoceanic

water treader, any insect of the approximately 30 species of the family Mesoveliidae (order Heteroptera). These small, slender insects are yellowish or greenish in colour and are 5 millimetres (0.2 inch) or less in length. Mesoveliids are predaceous and are usually seen on floating vegetation or on

water purification, process by which undesired chemical compounds, organic and inorganic materials, and biological contaminants are removed from water. That process also includes distillation (the conversion of a liquid into vapour to condense it back to liquid form) and deionization (ion removal

tupelo: Major species: The water tupelo (N. aquatica), also called cotton gum or swamp gum, grows in swamps of the southeastern and Gulf of Mexico coasts and in the Mississippi River valley northward to southern Illinois. It grows in pure stands or in association with bald cypress and other…

turbine: Water turbines: Water turbines are generally divided into two categories: (1) impulse turbines used for high heads of water and low flow rates and (2) reaction turbines normally employed for heads below about 450 metres and moderate or high flow rates. These two classes include…

darter, any of two to four species of bird of the family Anhingidae (order Pelecaniformes or Suliformes). The American species, Anhinga anhinga, is widely acknowledged as distinct, but there is debate regarding whether the darters that appear in Africa, Asia, and Oceania constitute one species (A.

sound reception: Turtles: …that turtles of the species Pseudemys scripta, trained to withdraw their head, respond to sound over the low-frequency range, with the greatest sensitivity in the region of 200 to 640 hertz. This result is in close agreement with electrophysiological observations in which it has been found that impulses could be…

air: …gases present in variable concentrations, water vapour, ozone, carbon dioxide, sulfur dioxide, and nitrogen dioxide are of principal importance. The typical concentration ranges of these gases (in percentage by volume) are as follows:

global warming: Water vapour feedback: …is known as the “water vapour feedback.” It is the primary reason that climate sensitivity is substantially greater than the previously stated theoretical value of 0.25 °C (0.45 °F) for each increase of 1 watt per square metre of radiative forcing.

wave, a ridge or swell on the surface of a body of water, normally having a forward motion distinct from the oscillatory motion of the particles that successively compose it. The undulations and oscillations may be chaotic and random, or they may be regular, with an identifiable wavelength between

aquifer: Wells can be drilled into many aquifers, and they are one of the most important sources of fresh water on Earth.

loosestrife: Swamp loosestrife, water willow, or wild oleander (Decodon verticillatus) is a perennial herb native to swamps and ponds of eastern North America.

Water Witch incident, (1855), brief military skirmish near the Paraguayan Ft. Itapirú, involving the USS “Water Witch,” commanded by Lt. Thomas J. Page, and Paraguayan troops who fired as the vessel was exploring the Paraná River, in international waters. In 1853 the “Water Witch” set out on a

George Lamming: Lamming’s later novels included Water with Berries (1971), a political allegory based on William Shakespeare’s The Tempest, and Natives of My Person (1971), about 16th-century explorers in the West Indies. His poetry and short stories were published in various anthologies, and Conversations, a volume of essays and interviews, was…

yam: Major species: trifida) and winged, or water, yam (D. alata) are the edible species most widely diffused in tropical and subtropical countries. The tubers of D. alata sometimes weigh 45 kg (100 pounds). Guinea yam (D. rotundata) and yellow Guinea yam (D. cayenensis) are the main yam species grown…

groundwater, water that occurs below the surface of Earth, where it occupies all or part of the void spaces in soils or geologic strata. It is also called subsurface water to distinguish it from surface water, which is found in large bodies like the oceans or lakes or which flows overland in

ordeal: …test, particularly by fire or water, is the most common. In Hindu codes a wife may be required to pass through fire to prove her fidelity to a jealous husband; traces of burning would be regarded as proof of guilt. The practice of dunking suspected witches was based on the…

children’s literature: Coming of age (1865–1945): In 1863 there appeared The Water-Babies by Charles Kingsley. In this fascinating, yet repulsive, “Fairy Tale for a Land-Baby,” an unctuous cleric and a fanciful poet, uneasily inhabiting one body, collaborated. The Water-Babies may stand as a rough symbol of the bumpy passage from the moral tale to a…

hormone: Neurohypophysis and the polypeptide hormones of the hypothalamus: …arginine vasotocin evokes the so-called Brunn (water-balance) response; that is, water accumulates within the body as a result of a combination of increased water uptake through the skin and the wall of the bladder and decreased urinary output. This response, which also involves the uptake of sodium by the skin,…

aquifer, in hydrology, rock layer that contains water and releases it in appreciable amounts. The rock contains water-filled pore spaces, and, when the spaces are connected, the water is able to flow through the matrix of the rock. An aquifer also may be called a water-bearing stratum, lens, or

China: Economic development: These water-control projects varied in scale with terrain and ecology. In central and southern China, irrigation systems were the foundation for rice cultivation and were largely the product of private investment and management. In northern China, control of the heavily silted Huang He (Yellow River), which…

nuclear reactor: Water-cooled, plate-fuel reactors: These are the most common type of research reactor. Water-cooled, plate-fuel reactors use enriched uranium fuel in plate assemblies (see above Fuel types) and are cooled and moderated with water. They operate over a wide range of thermal power levels, from a…

sponge: Form and function: …canals and chambers, called a water-current system, through which water circulates to bring food and oxygen to the sponge. The water-current system also helps disperse gametes and larvae and remove wastes.

chemical industry: Nitrogen: …possible to carry out a water-gas shift reaction by passing the water gas with more steam over a catalyst, yielding more hydrogen, and carbon dioxide. The carbon dioxide is removed by dissolving it in water at a pressure of about ten atmospheres; it can also be utilized directly, as noted…

pharmaceutical industry: Liquid dosage forms: …readily with water-based liquids, while water-in-oil emulsions mix more easily with oils. Milk is a common example of an oil-in-water emulsion. In order to prevent the separation of the two liquids, most pharmaceutical emulsions contain a naturally occurring emulsifying agent such as cholesterol or tragacanth or a synthetic emulsifying agent…

mining: Unit operations: The advantages of water-jet channeling are that it cuts narrow, straight channels with very little noise and that it does not damage the wall surface.

machine tool: Water-jet machining: In the water-jet machining process, water is forced through tiny nozzles under very high pressures to cut through materials such as polymers, brick, and paper. Water-jet machining has several advantages over other methods: it generates no heat, the workpiece does not deform during machining,…

John Irving: First novels and The World According to Garp: …Irving’s debut and the subsequent The Water-Method Man (1972) received enthusiastic notices, but The 158-Pound Marriage (1974) was roundly panned.

Coleoptera: Annotated classification: Family Psephenidae (water-penny beetles) Larvae flat, almost circular; a few species, mostly in India, North America. Family Ptilodactylidae About 200 tropical species; aquatic or in rotten wood. Superfamily Chrysomeloidea Mostly wood or plant feeders;

inorganic polymer: Silicones: Silicones are also water-repellent. Paper, wool, silk, and other fabrics can be coated with a water-repellent film by exposing them for a short time (one to two seconds) to the vapour of trimethylchlorosilane, (CH3)3SiCl. The ―OH groups on the surface of the materials react with the silane, and…

spirogyra, (genus Spirogyra), any member of a genus of some 400 species of free-floating green algae (division Chlorophyta) found in freshwater environments around the world. Named for their beautiful spiral chloroplasts, spirogyras are filamentous algae that consist of thin unbranched chains of

echinoderm: Water-vascular system: The water-vascular system, which functions in the movement of tube feet, is a characteristic feature of echinoderms, and evidence of its existence has been found in even the oldest fossil forms. It comprises an internal hydraulic system of canals and reservoirs containing a…

grebe, (order Podicipediformes), any member of an order of foot-propelled diving birds containing a single family, Podicipedidae, with about 20 species. They are best known for the striking courtship displays of some species and for the silky plumage of the underparts, which formerly was much used

Waterberg Series, major division of rocks in southern Africa. The age of the Waterberg is in doubt; it is possible that the Waterberg is late Precambrian or Early Paleozoic (older or younger than 540 million years, respectively). Waterberg rocks consist of several thousand feet of brown, red, and

Waterberg Series, major division of rocks in southern Africa. The age of the Waterberg is in doubt; it is possible that the Waterberg is late Precambrian or Early Paleozoic (older or younger than 540 million years, respectively). Waterberg rocks consist of several thousand feet of brown, red, and

waterboarding, method of torture in which water is poured into the nose and mouth of a victim who lies on his back on an inclined platform, with his feet above his head. As the victim’s sinus cavities and mouth fill with water, his gag reflex causes him to expel air from his lungs, leaving him

South Africa: British occupation of the Cape: Griqua raiding states led by Andries Waterboer, Adam Kok, and Barend Barends captured more Africans from among people such as the Hurutshe, Rolong, and Kwena. Other people, such as those known as the Mantatees, were forced to become farmworkers, mainly in the eastern Cape. European farmers also raided for labor…

South Africa: Diamonds and confederation: …the western Griqua under Nicolaas Waterboer, and southern Tswana chiefs. At a special hearing in October 1871, Robert W. Keate (then lieutenant governor of Natal) found in favor of Waterboer, but the British persuaded him to request protection against his Boer rivals, and the area was annexed as Griqualand West.

Adam Sandler: Early film career: Happy Gilmore, The Wedding Singer, and Punch-Drunk Love: …of financial necessity, and in The Waterboy (1998) he played the emotionally stunted water boy of a college football team who becomes its unlikely savior. In The Wedding Singer (1998), a romantic comedy with Drew Barrymore, and Big Daddy (1999), in which his character adopts a child to impress his…

waterbuck, antelope species of the genus Kobus

cockroach: Family Ectobiidae: The German cockroach (Blattella germanica), a common household pest, is light brown with two dark stripes on the prothoracic region. The female produces an ootheca 3 days after mating and carries it for about 20 days. Three or more generations may occur yearly. Because it is…

Namibia: The German conquest: …main Herero army at the Battle of Waterburg and, taking no prisoners, drove them into the Kalahari, where most died. By 1910 the loss of life by hanging, battle, or starvation and thirst—plus the escape of a few to the Bechuanaland protectorate—had reduced the Herero people by about 90 percent…

Waterbury, city, coextensive with the town (township) of Waterbury, New Haven county, west-central Connecticut, U.S., on the Naugatuck River. Mattatuck Plantation, settled in 1674 as part of Farmington, was incorporated (1686) as the town of Waterbury, so named because of the abundant drainage of

watercolour, pigment ground in gum, usually gum arabic, and applied with brush and water to a painting surface, usually paper; the term also denotes a work of art executed in this medium. The pigment is ordinarily transparent but can be made opaque by mixing with a whiting and in this form is known

watercolour, pigment ground in gum, usually gum arabic, and applied with brush and water to a painting surface, usually paper; the term also denotes a work of art executed in this medium. The pigment is ordinarily transparent but can be made opaque by mixing with a whiting and in this form is known

watercolour, pigment ground in gum, usually gum arabic, and applied with brush and water to a painting surface, usually paper; the term also denotes a work of art executed in this medium. The pigment is ordinarily transparent but can be made opaque by mixing with a whiting and in this form is known