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ocher
(Encyclopedia)ocher ōˈkər [key], mixture of varying proportions of iron oxide and clay, used as a pigment. It occurs naturally as yellow ocher (yellow or yellow-brown in color), the iron oxide being limonite, or...Falmouth, town, England
(Encyclopedia)Falmouth fălˈməth [key], town, Cornwall, SW England, on a small peninsula between Falmouth ...ammonium nitrate
(Encyclopedia)ammonium nitrate, chemical compound, NH4NO3, that exists as colorless, rhombohedral crystals at room temperature but changes to monoclinic crystals when heated above 32℃. It is extremely soluble in ...Iceland spar
(Encyclopedia)Iceland spar, colorless variety of crystallized calcite, characterized by its properties of transparency and double refraction. It is used chiefly in the manufacture of Nicol prisms, which are essenti...tracer
(Encyclopedia)tracer, an identifiable substance used to follow the course of a physical, chemical, or biological process. In chemistry the ideal tracer has the same chemical properties as the molecule it replaces a...silicate
(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...Pylos
(Encyclopedia)Pylos pīˈlŏs [key], ancient harbor, Messenia, SW Greece, on a bay of the Ionian Sea. Excavations have revealed a great Mycenaean palace of the 13th cent. b.c., perhaps the dwelling of King Nestor. ...chalk
(Encyclopedia)chalk, mineral of calcium carbonate, similar in composition to limestone, but softer. It is characteristically a marine formation and sometimes occurs in great thickness; the chief constituents of the...Bantu
(Encyclopedia)Bantu bănˈto͞oˌ [key], ethnic and linguistic group of Africa, numbering about 120 million. The Bantu inhabit most of the continent S of the Congo River except the extreme southwest. The classifica...superfluidity
(Encyclopedia)superfluidity, tendency of liquid helium below a temperature of 2.19K to flow freely, even upward, with little apparent friction. Helium becomes a liquid when it is cooled to 4.2K. Special methods...Browse by Subject
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