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National Road

(Encyclopedia)National Road, U.S. highway built in the early 19th cent. At the time of its construction, the National Road was the most ambitious road-building project ever undertaken in the United States. It final...

francium

(Encyclopedia)francium frănˈsēəm [key] [from France], radioactive chemical element; symbol Fr; at. no. 87; mass no. of most stable isotope 223; m.p. about 27℃ (estimated); b.p. 677℃ (estimated); sp. gr. unk...

brass

(Encyclopedia)brass, alloy having copper (55%–90%) and zinc (10%–45%) as its essential components. The properties of brass vary with the proportion of copper and zinc and with the addition of small amounts of o...

Dinoflagellata

(Encyclopedia)dinoflagellata dīˌnōflăjˌəlätˈə, –lāˈtə [key], phylum (division) of unicellular, mostly marine algae, called dinoflagellates. In some classification systems this division is called Pyrrh...

acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

topology

(Encyclopedia) CE5 Möbius strip: On the ordinary flat loop (A), an ant walking along the middle of the strip will pass only around the outside of the strip. If the strip is cut along the dotted line, twisted onc...

Cavendish, Henry

(Encyclopedia)Cavendish, Henry, 1731–1810, English physicist and chemist, b. Nice. He was the son of Lord Charles Cavendish and grandson of the 2d duke of Devonshire. He was a recluse, and most of his writings we...

Landau, Lev Davidovich

(Encyclopedia)Landau, Lev Davidovich lyĕf dəvēˈdəvĭch ləndouˈ [key], 1908–68, Soviet physicist, b. Baku, Azerbaijan. A child prodigy in mathematics, he entered Baku Univ. at 14; at 21 he received a doctor...

silica

(Encyclopedia)silica or silicon dioxide, chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. It occurs in sev...

herbal

(Encyclopedia)herbal, early botanical book containing descriptions and illustrations of herbs and plants with their properties, chiefly those qualities that made them useful as medicines or condiments. Most of the ...
 

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