Rostov-na-Donu or Rostov on the Don, city (1989 pop. 1,019,000), capital of Rostov region and the administrative center of the North Caucasus district, SE European Russia, on the Don River near its entrance into the Sea of Azov. It is a major port and rail hub and an important industrial, cultural, and scientific center. One of Russia's leading producers of agricultural machinery, Rostov-na-Donu also has ship and locomotive repair yards, plants processing food and tobacco, mechanical engineering works, and factories that manufacture chemicals, building materials, electrical equipment, road-making machinery, furniture, clothing, footwear, and leather goods. A customshouse was built on the site in 1749, but the city grew around a fortress erected in 1761 and named for St. Dmitri of Rostov. Chartered in 1797, it was named Rostov-na-Donu to distinguish it from the older city of Rostov. It grew rapidly after the opening of its port in 1834 and was a major grain-exporting center throughout the 19th cent. Its position as a center for trade between European Russia and the Caucasus area also gave it the name "Gateway to the Caucasus." The city suffered much damage in World War II and had to be rebuilt after the war.

Na, symbol for the element sodium.

Myles na Gopaleen: see O'Brien, Flann.

Masséna, André, 1758-1817, marshal of France, b. Nice. Of humble origin, he entered (1791) the French army and rose rapidly because of his brilliant tactical abilities. He served under Napoleon Bonaparte in the Italian campaign, won the battle of Rivoli (1797), where he earned a reputation for rapaciousness, and distinguished himself in Napoleon's campaigns of 1800 and 1809 against Austria. In 1799, Masséna's victory over the Russians at Zürich saved France from invasion by the Second Coalition (see French Revolutionary Wars). Masséna's subsequent failure in the Peninsular War is often attributed to the lack of cooperation of the other French commanders. Masséna's relations with Napoleon were somewhat strained because of Masséna's republican convictions, but he lacked political ambition, and Napoleon honored his military achievements by making him duke of Rivoli (1808) and prince of Essling (1810). After Napoleon's fall in 1814, Masséna supported Louis XVIII, who raised him to the peerage (1815). His neutral attitude during the Hundred Days was attacked by the royalists after the Restoration.

Ma-na-ssu: see Manas, China.

Düna: see Dvina (Western Dvina), river.

English Rostov-on-Don

City (pop., 2002: 1,070,200), southwestern Russia. Located on the Don River about 30 mi (50 km) from the Sea of Azov, it was founded as a customs post in 1749. It was fortified soon after, and, because of its key position as a transport centre and port, it grew steadily with 19th-century Russian colonization. Occupied by the Germans in World War II, it suffered extensive damage but was rebuilt after the war. It is a transportation and industrial centre. The city's nodal location and the proximity of the Donets Basin have led to major industrial development, especially in engineering.

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Chemical element, one of the alkali metals, chemical symbol Na, atomic number 11. A very soft, silvery white metal, the sixth most abundant element on Earth, it occurs mainly as halite, never free. Extremely reactive, it is used as a chemical reagent and raw material, in metallurgy, as a heat exchanger (in nuclear power generators and certain types of engines), and in sodium-vapour lamps (see electric discharge lamp). Sodium is essential for life but rarely deficient in diets; high intake is linked to hypertension. Sodium in compounds, many of great industrial importance (including bicarbonate of soda, caustic soda, sodium nitrate [Chile saltpetre], and sodium chloride), has valence 1. Sodium carbonate, one of the four most important basic chemical commodities, is used in making glass, detergents, and cleansers. Sodium hypochlorite, familiar as household bleach, is also used to bleach paper pulp and textiles, to chlorinate water, and in some medicines. The sulfate is used in the kraft process and also used to make paperboard, glass, and detergents. The thiosulfate (hyposulfite, or “hypo”) is used to developed photographs.

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