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mining

(Encyclopedia)mining, extraction of solid mineral resources from the earth. These resources include ores, which contain commercially valuable amounts of metals, such as iron and aluminum; precious stones, such as d...

promethium

(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...

Lind, James

(Encyclopedia)Lind, James, 1716–94, English naval surgeon. Considered the founder of naval hygiene in England, Lind observed on a ten-week cruise (1746) that 80 seamen of 350 came down with scurvy. In his Treatis...

Lenard, Philipp Eduard Anton

(Encyclopedia)Lenard, Philipp Eduard Anton fēˈlĭp āˈdo͞oärt änˈtōn lāˈnärt [key], 1862–1947, German physicist, b. Bratislava. After serving as professor at the universities of Kiel (1898–1907) and ...

mezzotint

(Encyclopedia)mezzotint mĕtˈsətĭnt, mĕdˈzə–, mĕzˈə– [key] [Ital.,=halftint], method of copper or steel engraving in tone. A Dutch officer, Ludwig von Siegen, is given credit for the invention of mezzo...

John Paul I

(Encyclopedia)John Paul I, 1912–78, pope (1978), an Italian (b. Canale d'Agordo) named Albino Luciani; successor of Paul VI. Born into a poor, working-class family, he trained at local seminaries and at the Grego...

Mott, Sir Nevill

(Encyclopedia)Mott, Sir Nevill, 1905–96, British physicist. A professor at the Univ. of Bristol (1933–54) and the Univ. of Cambridge (1954–71), Mott won the Nobel Prize in Physics in 1977 for a lifetime of re...

Haldane, John Scott

(Encyclopedia)Haldane, John Scott, 1860–1936, British scientist, b. Edinburgh; father of John Burdon Sanderson Haldane. He made many important contributions to mine safety, investigating principally the action of...

Goyen, Jan Josephszoon van

(Encyclopedia)Goyen, Jan Josephszoon van yän yōˈzəfsōn vän gōˈyən [key], 1596–1656, Dutch landscape painter. He studied at Leiden and Haarlem. In 1631 he settled at The Hague. His typically Dutch landsca...

ground bass

(Encyclopedia)ground bass, melodic phrase used repeatedly as a bass line. In its earlier form, developed in the 13th and 14th cent., the ground or basso ostinato [Ital.,=obstinate] never varied in harmonization or ...