Vratsa

Also spelled  Vratca >, or  Vraca  town, northwestern Bulgaria. It is situated in the northern foothills of the western Balkan Mountains at the point where the Leva River emerges from its picturesque Vratsata gorge. The town was moved to its present position in the early 15th century after the Turks had destroyed a previously standing Bulgarian fortress. Under the Turks, Vratsa was a prosperous trading

Light

Electromagnetic radiation that can be detected by the human eye. In terms of wavelength, electromagnetic radiation occurs over an extremely wide range, from gamma rays with a wavelength of 3 10-14 centimetre to long radio waves measured in millions of kilometres. In that spectrum the wavelengths visible to humans occupy a very narrow band, from about 7 10-5 centimetre (red light)

Amon

Amon may have been originally a local deity at Khmun (Hermopolis) in Middle Egypt; his cult reached Thebes, where he became the patron of the pharaohs by the reign of Mentuhotep I (2008–1957 BC). At that date he was already identified with the sun god Re of Heliopolis and, as Amon-Re, was received as a national god. Represented in human form,

Quechuan Languages

The languages of the former Inca Empire in South America and the principal native languages of the central Andes today. According to archaeological and historical evidence, the original languages were probably spoken in a small area in the southern Peruvian highlands until about 1450; after that their geographical range was rapidly enlarged by the Inca conquests.

Moivre, Abraham De

A French Huguenot, de Moivre was jailed as a Protestant upon the revocation of the Edict of Nantes in 1685. When he was released shortly thereafter, he fled to England. In London he became a close friend of Sir Isaac Newton and the astronomer

Voyager

Voyager 2, launched on Aug. 20, 1977, traveled more slowly than its

Ringsaker

Town, Hedmark fylke (county), southeastern Norway. It lies along the eastern shore of Mjøsa, the largest lake in Norway. Situated along the main road and rail line between Oslo and Trondheim, Ringsaker lies in a rich agricultural and lumbering region. Tourism is based mainly on the scenery of the lake area, a 12th-century church, and a nearby 13th-century castle. Pop. (1989 est.) mun., 30,960.

Saimaa, Lake

Lake in southeastern Finland. It lies just northwest of the Russian border and is northeast of Helsinki. Covering parts of the läänit (provinces) of Mikkeli and Kymi, it has an area of 443 square miles (1,147 square km) and is the primary lake in the Great Saimaa lake system, which, at 1,690 square miles (4,377 square km), is the largest system in Finland. The lake's two branches extend northward about

Halévy, (jacques-françois-) Fromental(-élie)

Halévy studied at the Paris Conservatoire from the age of 10 and won the Prix de Rome in 1819 for his cantata Herminie. His first opera performed was L'Artisan (1827), but it was not until Le Dilettante d'Avignon

Aspergillus

Genus of the Fungi Imperfecti (form-class Deuteromycetes). Those species for which the sexual phase is known are placed in the order Eurotiales. A. niger causes black mold of foodstuffs; A. flavus, A. niger, and A. fumigatus cause aspergillosis in humans. A. oryzae is used to ferment sake, and A. wentii to process soybeans. Three genera of the class Ascomycetes have

Earn

Loch (lake) and river, central Scotland. Loch Earn lies on the boundary between the council area of Stirling and the council area of Perth and Kinross, and the River Earn flows through Perth and Kinross. Loch Earn is 6.5 miles (10.5 km) from east to west with a maximum width of 0.5 mile (0.8 km). Lochearnhead is situated at the western end of the loch and St. Fillan's village at the eastern extremity,

Intaglio

In sculpture, work in which the design is incised into the block, all lines appearing below the surface; it is thus the opposite of relief sculpture and is sometimes called “hollow relief.” When the technique is used in casting, the design is cut in reverse into a plaster shell, which is then filled with the casting substance; the hollow impressions of the mold appear in