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Galápagos Islands

(Encyclopedia)Galápagos Islands gəlăpˈəgōs [key] [Span.,=tortoises], archipelago and province, 3,029 sq mi ...

Oligocene epoch

(Encyclopedia)Oligocene epoch ŏlˈəgōsēnˌ [key], third epoch of the Tertiary period in the Cenozoic era of geologic time, lasting from 38 to 24 million years ago. More of North America was dry land during the ...

mantle

(Encyclopedia)mantle, portion of the earth's interior lying beneath the crust and above the core. No direct observation of the mantle, or its upper boundary, has been made; its boundaries have been determined solel...

electrophorus

(Encyclopedia)electrophorus, device used to generate static electric charges. It has two parts: a nonconducting plate (e.g., of hard rubber) that is negatively charged and a metal plate with an insulated handle. A ...

seafloor spreading

(Encyclopedia)CE5 Schematic model of the oceanic crust, showing seafloor spreading seafloor spreading, theory of lithospheric evolution that holds that the ocean floors are spreading outward from vast underwate...

Tertiary period

(Encyclopedia)Tertiary period tûrˈshēĕrˌē [key], name for the major portion of the Cenozoic era, the most recent of the geologic eras (see Geologic Timescale, tablegeologic timescale, table) from around 26 to...

drypoint

(Encyclopedia)drypoint, an intaglio printing process in which the lines are scratched directly into a metal plate with a needle; also, the print made from such a plate. Although it is often used in combination with...

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 ...

horseshoe

(Encyclopedia)horseshoe, narrow plate, commonly of iron or steel, shaped to fit a horse's hoof and attached to the hoof by nailing it to the inner edge of the horny wall of the hoof. Horseshoes vary from the light ...

holography

(Encyclopedia)holography hŏlŏgˈrəfē, hō– [key], method of reproducing a three-dimensional image of an object by means of light wave patterns recorded on a photographic plate or film. Holography is sometimes...