Sills, Beverly orig. Belle Silverman (b. May 25, 1929, New York, N.Y., U.S.) U.S. soprano. She sang on radio as a child and made her oper¬ atic debut in 1946. From 1955 she sang with the New York City Opera. After gaining attention for her coloratura performance in Julius Caesar (1966), she became one of the most celebrated opera stars in the world. After 25 years of singing with the company, she served as its director (1979-89). She sang with the Metropolitan Opera as well (1975-80), though after her prime. An effervescent personality, she hosted broadcast concerts and opera performances, becoming popular among a wide public.
Siloe\se-lo-'a\, Diego de (b. c. 1495, Burgos, Spain—d. Oct. 22,1563, Granada) Spanish sculptor and architect. Son of the sculptor Gil de Siloe (d. 1501?), he probably studied sculpture in Italy. His works are consid¬ ered among the finest of the Spanish Renaissance. His sculptural style is Plateresque, a mixture of Italian Renaissance, Gothic, and Mudejar styles. His principal architectural work, the Granada Cathedral (begun 1528), combines the best features of those styles.
Silone \se-'lo-na\, Ignazio orig. Secondo Tranquilli (b. May 1,
1900, Pescina dei Marsi, Italy—d. Aug. 22, 1978, Geneva, Switz.) Ital¬ ian novelist, short-story writer, and political leader. A founder of the Ital¬ ian Communist party in 1921, he was active in the party until the fascists drove him into exile. In 1930 he settled in Switzerland, became disillu¬ sioned with communism, and began to write antifascist works. He became internationally famous with his first novel, Fontamara (1930), which was followed by the novels Bread and Wine (1937) and The Seed Beneath the Snow (1940) and the satire The School for Dictators (1938). After World War II he returned to Italian politics before retiring to write such works as A Handful of Blackberries (1952).
silt Sediment particles 0.00016-0.0024 in. (0.004-0.06 mm) in diameter, regardless of mineral type. Silt is easily transported by moving currents but settles in still water. An unconsolidated aggregate of silt particles is also called silt, whereas a consolidated aggregate is called siltstone. Silt deposits formed by wind are known as loess. Sediments are seldom com¬ posed entirely of silt but rather are a mixture of clay, silt, and sand. Clay- rich silt, upon consolidation, frequently develops parting along bedding surfaces and is then called shale. If parting does not develop, the massive rock is called mudstone.
siltstone Hardened sedimentary rock that is composed primarily of angular silt-sized particles (see silt) and that is not laminated or easily split into thin layers. Siltstones, which are hard and durable, occur in thin lay¬ ers rarely thick enough to be classified as formations. They are interme¬ diate between sandstones and shales but are not as common as either.
Silurian \sl-'lur-e-3n\ Period Interval of geologic time, 443^-17 mil¬ lion years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appear¬ ance of land plants and jawed fishes. The continents were distributed as follows: Arctic Canada, Scandinavia, and Australia were probably in the tropics; Japan and the Philippines may have been inside the Arctic Circle; South America and Africa were likely near the South Pole, with either present-day Brazil or western Africa as the locus of the pole. The land surface was buried by an ice sheet, possibly as deep as that covering Ant¬ arctica today.
Silvassa \,sil-va-'sa\ Town (pop., 2001 prelim.: 21,890), capital of Dadra and Nagar Haveli union territory, western India. Located on the Daman Ganga River some 15 mi (25 km) from the Arabian Sea, it is the economic centre of the territory, which produces rice, pulses, and fruit crops.
silver Metallic chemical element, one of the transition elements, chemical symbol Ag, atomic number 47. It is a white, lustrous precious metal, val¬ ued for its beauty. It is also valued for its electrical conductivity, which is the highest of any metal. Between copper and gold in their common group of the periodic table, it is inter¬ mediate between them in many prop¬ erties. Widely distributed in nature in small amounts, as the native metal and in ores, it is usually recovered as a by-product of copper and lead pro¬ duction. Its use in bullion and coins was overtaken in the 1960s by demand for industrial purposes, especially photography. It is also used in printed electrical circuits, electronic conductors, and contacts.
It is the catalyst for converting eth¬ ylene to ethylene oxide, the precur¬ sor of many organic chemicals. Its use in alloys in sterling (92.5% sil¬ ver, 7.5% copper) and plated silver¬ ware, ornaments, and jewelry remains important; yellow gold used in jewelry is typically 25% silver, and gold dental alloys are about 10% silver. Silver dental fillings are an amalgam of silver and mercury. Silver in compounds, the most important of which is silver nitrate, has valence 1 . Its chloride, bromide, and iodide are used in photography and its iodide in cloud seeding.
Silver, Horace (b. Sept. 2, 1928, Norwalk, Conn., U.S.) U.S. jazz pia¬ nist, composer, and bandleader. Silver performed with Stan Getz in 1950-51 before leading his own trio in 1952. With Art Blakey he led the Jazz Messengers from 1954, then formed his own quintet in 1956, per¬ forming his own compositions in arrangements that provided the template for much of the hard bop (see bebop) of the 1950s and ’60s. Influenced by Bud Powell and Thelonious Monk, Silver combined the sophistication of bebop with the earthiness of the blues in compositions such as “The Preacher,” “Opus de Funk,” and “Sister Sadie.”
Silver Age In Latin literature, the period from c. ad 18 to 133, second only to the preceding Golden Age in literary achievement. Satire was the most vigorous literary form, exemplified by Juvenal, AAartial, and Petro- nius. Other figures included Tacitus and Suetonius in history, Puny the Elder and Puny the Younger in letter writing, and Quintilian in literary criticism. Prose was characteristically elaborate and poetical in style, and many of the best works of the period were psychologically perceptive and human¬ ist in tone. See also Augustan Age.
silver nitrate Inorganic compound (AgN0 3 ), colourless, transparent crystals with a bitter, caustic, metallic taste. The most important silver compound, it is used to prepare other silver salts, to silver mirrors, and as a reagent in analysis. It is very soluble in water; dilute solutions are effective against gonococcal bacteria and may be applied to newborns’ eyes to prevent blindness from gonorrhea. Ingesting silver nitrate causes violent abdominal pain and gastroenteritis.
silver salmon See coho
Dendritic (branching) silver from Ontario
COURTESY OF JOSEPH AND HELEN GUETTERMAN COLLECTION; PHOTOGRAPH, JOHN H. GERARD
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1754 I silver standard ► Simon
silver standard Monetary standard under which the basic unit of cur¬ rency is defined as a stated quantity of silver. It is usually characterized by the coinage and circulation of silver, unrestricted convertibility of other money into silver, and the free import and export of silver for the settle¬ ment of international obligations. No country now operates under a sil¬ ver standard. In the 1870s most European countries adopted the gold standard, and by the early 1900s only China, Mexico, and a few small countries still used the silver standard. In 1873 the U.S. Treasury stopped coining silver, which led to the Free Silver Movement, but the defeat of William Jennings Bryan ended agitation for free silver in the U.S. See also BIMETALLISM.
silverfish Species ( Lepisma saccharina ) of quick-moving, slender, flat, wingless insect having three tail bristles and silvery scales. Silverfish are found worldwide. Females deposit fertilized eggs in cracks and hidden places. The hatched young are scaleless and have short appendages. Sil¬ verfish normally live indoors and, because they eat starchy materials (e.g., paste, bookbindings, and wallpaper), can cause much damage. They live two to three years and molt throughout life.