SATELLITE (from the

See also:

• LAT

Lat. satelles, an attendant)  , in astronomy, a small opaque body revolving around a planet, as the moon around the earth (see PLANET) . In the theory of cubic curves, Arthur Cayley defined the satellite of a given line to be the line joining the three points in which tangents at the intersections of the given (primary) line and curve again meet the curve . SATIN-SPAR, a name given to certain fibrous minerals which exhibit, especially when polished, a soft satiny or silky lustre, and are therefore sometimes used as ornamental stones . Such fibrous minerals occur usually in the form of veins or bands, having the fibres disposed transversely . The most common kind of satin-spar is a white finely-fibrous gypsum not infrequently found in the Keuper marls of Nottinghamshire and Derbyshire, and used for beads, &c . Other kinds of satin-spar consist of calcium carbonate, in the form of either aragonite or calcite, these being distinguished from the fibrous gypsum by greater hardness, and from each other by specific gravity and optical characters . The satin-spar of Alston, Cumberland, is a finely-fibrous calcite occurring in veins in a black shale of the Carboniferous series . Fibrous calcite is known sometimes to German mineralogists as Atlasspath . SATIN-WOOD, a beautiful light-coloured hard wood, having a rich, silky lustre, sometimes finely mottled or grained, the produce of a moderate-sized tree, Chloroxylon Swietenia (natural order Meliaceae), native of India and Ceylon . A similar wood, known under the same name, is obtained in the West Indies, the tree being probably a species of Zanthoxylum (natural order Rutaceae) . Satin-wood was in request for rich furniture about the end of the 18th century, the fashion then being to ornament panels of it with painted medallions and floral scrolls and borders . It is used for inlaying and small veneers, in covering the backs of hair and clothes-brushes and in making small articles of turnery .