Frankish count and historian whose works, utilizing important sources and official documents, provide an invaluable firsthand account of contemporary events during the reign of the West Frankish king Charles II.
valley of the River Nith, Dumfries and Galloway region, southwestern Scotland. It comprises the western part of the historic county of Dumfriesshire and a small portion of eastern Kirkcudbrightshire. The valley's upper end lies along the border with Ayrshire, where ...
one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). Occupying 1.6 percent of the total land surface on Earth, Nitisols are found mainly in eastern Africa at higher altitudes, coastal India, Central ...
any member of either of two classes of compounds derived from nitric acid. The salts of nitric acid are ionic compounds containing the nitrate ion, NO-3, and a positive ion, such as NH+4 in ammonium nitrate. Esters of nitric acid ...
small group of naturally occurring inorganic compounds that are practically confined to the Atacama Desert of northern Chile; the principal locality is Antofagasta. These minerals occur under the loose soil as beds of grayish caliche (a hard cemented mixture of ...
(HNO3), colourless, fuming, and highly corrosive liquid (freezing point -42° C [-44° F], boiling point 83° C [181° F]) that is a common laboratory reagent and an important industrial chemical for the manufacture of fertilizers and explosives. It is toxic ...
colourless, toxic gas that is formed by the oxidation of nitrogen. Though it has few industrial applications, nitric oxide performs important chemical signaling functions in humans and other animals and has various applications in medicine. It is also a serious ...
binary compound of nitrogen with a more electropositive element, such as boron, silicon, and most metals. Certain metal nitrides are unstable, and most react with water to form ammonia and the oxide or hydroxide of the metal; but the nitrides ...
any of a small group of aerobic bacteria (family Nitrobacteraceae) that use inorganic chemicals as an energy source. They are microorganisms that are important in the nitrogen cycle as converters of soil ammonia to nitrates, compounds usable by plants. The ...
any of a class of organic compounds having molecular structures in which a cyano group (&singlehorzbond;C ≡ N) is attached to a carbon atom (C). Nitriles are colourless solids or liquids with distinctive odours.
any member of either of two classes of compounds derived from nitrous acid. Salts of nitrous acid are ionic compounds containing the nitrite ion, NO-2, and a positive ion such as Na+ in sodium nitrite (NaNO2). Esters of nitrous acid ...
any of a family of chemical compounds in which the nitro group (&singlehorzbond;O&singlehorzbond;N&doublehorzbond;O) forms part of the molecular structure. The most common examples are organic substances in which a carbon atom is linked by a covalent bond to the nitrogen ...
the simplest aromatic nitro compound, having the molecular formula C6H5NO2. It is used in the manufacture of aniline, benzidine, and other organic chemicals. Nitrobenzene is a colourless to pale yellow, oily, highly toxic liquid with the odour of bitter almonds.
a mixture of nitric esters of cellulose, and a highly flammable compound that is the main ingredient of modern gunpowder. Nitrocellulose is a fluffy white substance that retains some of the fibrous structure of untreated cellulose. It is not stable ...
nonmetallic element of Group Va of the periodic table. It is a colourless, odourless, tasteless gas that is the most plentiful element in the Earth's atmosphere, and a constituent of all living matter.
circulation of nitrogen in various forms through nature. Nitrogen, a component of proteins and nucleic acids, is essential to life on Earth. Although 78 percent by volume of the atmosphere is nitrogen gas, this abundant reservoir exists in a form ...
any natural or industrial process that causes free nitrogen, which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more reactive nitrogen compounds such as ammonia, nitrates, or nitrites.
any of the chemical elements that constitute Group Va of the periodic table (see ). The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The elements share certain general similarities in chemical behaviour, though ...
effects produced by the gas nitrogen when it is breathed under increased pressure. Nitrogen, a major constituent of air, is quite inert and passes into the fluids and tissues of the body without undergoing chemical change. Even though it is ...
a powerful explosive and an important ingredient of most forms of dynamite (q.v.). It is also used with nitrocellulose in some propellants, especially for rockets and missiles, and it is employed as a vasodilator in the easing of cardiac pain.
synthetic mercury-containing organic compound used as an antiseptic for the skin and mucous membranes and as a disinfectant for sterilizing surgical instruments. It is related to merbromin (Mercurochrome) and thimerosal (Merthiolate). Nitromersol disinfects by the action of the mercury in ...
any of a class of organic compounds having molecular structures in which the nitroso group (-N&doublehorzbond;O) is attached to a carbon or nitrogen atom. Substances in which this group is attached to an oxygen atom are called nitrites, that is, ...
(HNO2), an unstable, weakly acidic compound that has been prepared only in the form of cold, dilute solutions. It is useful in chemistry in converting amines into diazonium compounds, which are used in making azo dyes. It is usually prepared ...
one of several oxides of nitrogen, a colourless gas with pleasant, sweetish odour and taste, which when inhaled produces insensibility to pain preceded by mild hysteria, sometimes laughter. Nitrous oxide was discovered by the English chemist Joseph Priestley in 1772; ...
Japanese warrior whose support of the imperial restoration of the emperor Go-Daigo was crucial in destroying the Kamakura shogunate, the military dictatorship that governed Japan from 1192 until 1333. The ultimate defeat of Nitta resulted in the end of the ...
northernmost island of Tonga, in the southwestern Pacific Ocean. The generally wooded land area of 19 square miles (49 square km) includes a volcanic peak 853 feet (260 m) high, a crater lake, and numerous hot springs. During a particularly ...
one of the northernmost islands of Tonga, in the southwestern Pacific Ocean. Of volcanic origin, the island has an area of 7 square miles (19 square km) and rises to 350 feet (110 m). Although the island lacks an adequate ...
internally self-governing island state in free association with New Zealand. It is the westernmost of the Cook Islands but is administratively separate from them. Niue lies 1,340 miles (2,156 km) northeast of Auckland and 240 miles (385 km) east of ...
commander in chief of the French armies on the Western Front for five months in World War I. His career was wrecked by the failure of his offensive in the spring of 1917.
in France, the area administered from Nevers during the ancien regime, and until the French Revolution the last great fief still not reunited to the French crown. Bounded southwest by Bourbonnais, west by Berry, north by Orleanais, and east by ...
east Siberian people who live in the region of the Amur River estuary and on nearby Sakhalin Island. They numbered about 4,600 in the late 20th century. Most speak Russian, though about 10 percent still speak Nivkh, a Paleo-Siberian language ...
isolated language with two main dialects spoken by some 400 Nivkh, roughly 10 percent of the ethnic group. The Nivkh live on Sakhalin Island and along the estuary of the Amur River in eastern Siberia. Nivkh is not known to ...
in Germanic mythology, a water being, half human, half fish, that lives in a beautiful underwater palace and mingles with humans by assuming a variety of physical forms (e.g., that of a fair maiden or an old woman) or by ...
American first lady (1969-74), the wife of Richard Nixon, 37th president of the United States, who espoused the cause of volunteerism during her husband's term.
37th president of the United States (1969-74), who, faced with almost certain impeachment for his role in the Watergate Scandal, became the first American president to resign from office. He was also vice president (1953-61) under President Dwight D. Eisenhower. ...
Persian vizier of the Turkish Seljuq sultans (1063-92), best remembered for his large treatise on kingship, Seyasat-nameh (The Book of Government; or Rules for Kings).
succession of rulers of the kingdom of Ahmadnagar in the Deccan of India from 1490 to 1633. The founder was Malik Ahmad, who in 1490 fixed his capital on a new site called Ahmadnagar after himself. The kingdom lay in ...
(Turkish: "new order"), originally a program of westernizing reforms undertaken by the Ottoman sultan Selim III (reigned 1789-1807). Later the term came to denote exclusively the new, regular troops established under this program.
(Arabic: "Governor of the Kingdom"), title borne by various Indian Muslim princes. The term has also been translated as "Deputy for the Whole Empire." In 1713 it was conferred on Chin Qilich Khan (Asaf Jah) by the Mughal emperor Muhammad ...
city, northwestern Andhra Pradesh state, southern India. The city is located on the Hyderabad-Godavari Valley line of the Central Railway, north-northwest of Hyderabad. Historical points of interest include a temple that now houses a water-supply tank and the fort of ...
oblast (province) in western Russia, in the middle of the Volga River basin. Nizhegorod oblast is bisected by the Volga River. The northern half of the oblast is a low plain, mostly in dense coniferous forest of spruce, pine, and ...
city, Tatarstan, western Russia. It lies along the left bank of the Kama River, just southwest of Naberezhnye Chelny. It is an important petrochemical centre. Its synthetic-rubber plant, intended to become one of the world's largest, began operation in 1970. ...
city and port, Khanty-Mansi autonomous okrug (district), Tyumen oblast (province), west-central Russia. It lies along the right bank of the Ob River. The city grew rapidly, especially in the 1970s, as a result of the discovery of large oil fields ...
city and administrative centre of Nizhegorod oblast ("region"), western Russia. The city lies at the confluence of the Volga and Oka rivers, 260 miles (420 km) east of Moscow.
city, Sverdlovsk oblast (province), western Russia. Nizhny Tagil lies along the Tagil River. One of the oldest smelting centres of the Ural Mountains region, it was founded in 1725 in connection with the construction of a metallurgical ...
river in western Siberia that is a right-bank tributary of the Yenisey River, flowing through Irkutsk oblast (province) and Krasnoyarsk kray (region) of Russia. Its length is 1,857 miles (2,989 km), and the area of its basin is 187,900 square ...
