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Tlingit

(Encyclopedia)Tlingit tlĭngˈgĭt [key], group of related Native North American tribes, speaking a language that forms a branch of the Nadene linguistic stock (see Native American languages). The 14 divisions of t...

solar time

(Encyclopedia)solar time, time defined by the position of the sun. The solar day is the time it takes for the sun to return to the same meridian in the sky. Local solar time is measured by a sundial. When the cente...

Philip V, king of Macedon

(Encyclopedia)Philip V, 238–179 b.c., king of Macedon (221–179), son of Demetrius II, successor of Antigonus III. He won fame in a war in Greece (220–217), in which he sided with the Achaean League against th...

photoelectric effect

(Encyclopedia)photoelectric effect, emission of electrons by substances, especially metals, when light falls on their surfaces. The effect was discovered by H. R. Hertz in 1887. The failure of the classical theory ...

saddle

(Encyclopedia)saddle, seat or pad to support the rider on an animal, chiefly a horse. The saddles mentioned in the Bible are generally considered to have been saddlecloths. The ancient Greeks sometimes used saddlec...

capacitor

(Encyclopedia)capacitor or condenser, device for the storage of electric charge. Simple capacitors consist of two plates made of an electrically conducting material (e.g., a metal) and separated by a nonconducting ...

differential geometry

(Encyclopedia)differential geometry, branch of geometry in which the concepts of the calculus are applied to curves, surfaces, and other geometric entities. The approach in classical differential geometry involves ...

field, in physics

(Encyclopedia)field, in physics, region throughout which a force may be exerted; examples are the gravitational, electric, and magnetic fields that surround, respectively, masses, electric charges, and magnets. The...

Eve, in genetics

(Encyclopedia)Eve, in genetics, popular term for a theoretical female ancestor of all living people, also known as Mitochondrial Eve. In 1987 biochemist Allan C. Wilson proposed that all living human beings had inh...

hydrogen chloride

(Encyclopedia)hydrogen chloride, chemical compound, HCl, a colorless, poisonous gas with an unpleasant, acrid odor. It is very soluble in water and readily soluble in alcohol and ether. It fumes in moist air. It is...