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etching

(Encyclopedia)etching, the art of engraving with acid on metal; also the print taken from the metal plate so engraved. In hard-ground etching the plate, usually of copper or zinc, is given a thin coating or ground ...

mordant

(Encyclopedia)mordant môrˈdənt [key] [Fr.,=biting], substance used in dyeing to fix certain dyes (mordant dyes) in cloth. Either the mordant (if it is colloidal) or a colloid produced by the mordant adheres to t...

hydrogen sulfide

(Encyclopedia)hydrogen sulfide, chemical compound, H2S, a colorless, extremely poisonous gas that has a very disagreeable odor, much like that of rotten eggs. It is slightly soluble in water and is soluble in carbo...

Atrato

(Encyclopedia)Atrato äträˈtō [key], river, c.415 mi (670 km) long, rising in the Cordillera Occidental, W Colombia. It meanders north, across the base of the Isthmus of Panama, to the Gulf of Urabá. Quibdo is ...

Lech

(Encyclopedia)Lech lĕkh [key], river, c.175 mi (280 km) long, rising in Vorarlberg, W Austria, and flowing NE into S Germany past Augsburg to the Danube River. The Wertach River is its chief tributary. There are a...

Frey

(Encyclopedia)Frey frā [key], Norse god. He was a beneficent deity associated with the fertilizing powers of the sun and the rain and, like his sister Freyja, with the return of spring. His worship, which extended...

LSD

(Encyclopedia)LSD or lysergic acid diethylamide līˌsûrˈjĭk, dīˌĕthˈələmĭd, dīˌĕthəlămˈĭd [key], alkaloid synthesized from lysergic acid, which is found in the fungus ergot (Claviceps purpurea). I...

cyclamate

(Encyclopedia)cyclamate sīˌkləmātˌ, –mət [key], any member of a group of salts of cyclamic acid (cyclohexanesulfamic acid). The sodium and calcium salts were commonly used as artificial sweeteners until 196...

pyrogallol

(Encyclopedia)pyrogallol –ĭk [key], C6H6O3, white, crystalline, aromatic compound with a biting taste; it is poisonous. It melts at 133℃ and boils at 309℃. In alkaline solution it is an active reducing agent...

fulminate

(Encyclopedia)fulminate fŭlˈmĭnāt [key], any salt of fulminic acid, HONC, a highly unstable compound known only in solution. The term is most commonly applied to the explosive mercury (II) fulminate, also calle...