Columbia Encyclopedia

Search results

500 results found

protactinium

(Encyclopedia)protactinium prōˌtăktĭnˈēəm [key], radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600℃; b.p. 4,026℃; sp. gr. 15.37 (calcula...

gadolinium

(Encyclopedia)gadolinium gădəlĭnˈēəm [key], metallic chemical element; symbol Gd; at. no. 64; at. wt. 157.25; m.p. 1,312℃; b.p. 3,233℃; sp. gr. 7.898 at 25℃; valence +3. Gadolinium is a malleable, ducti...

gallium

(Encyclopedia)gallium gălˈēəm [key], metallic chemical element; symbol Ga; at. no. 31; at. wt. 69.723; m.p. 29.78℃; b.p. 2,403℃; sp. gr. 5.904 at 29.6℃ (solid), 6.095 at 29.8℃ (liquid); valence +2 or +3...

Hogarth, William

(Encyclopedia)Hogarth, William, 1697–1764, English painter, satirist, engraver, and art theorist, b. London. At the age of 15 he was apprenticed to a silver-plate engraver. He soon made engravings on copper for b...

ink

(Encyclopedia)ink, pigmented fluid used for writing and drawing, or a viscous compound used for printing, both of various colors but most frequently black. The oldest known variety, India ink or China ink, is still...

Wilder, Laura Elizabeth Ingalls

(Encyclopedia)Wilder, Laura Elizabeth Ingalls, 1867–1957, American author of the classic Little House series of children's books, b. Pepin, Wis. She and her pioneer family traveled (1869–79) throughout the Midw...

Yukon, territory, Canada

(Encyclopedia)CE5 Yukon, territory (2001 pop. 28,674), 207,076 sq mi (536,327 sq km), NW Canada. The territory's history began with the explorations in the 1840s of Robert Campbell and John Bell, fur traders f...

lanthanum

(Encyclopedia)lanthanum lănˈthənəm [key] [Gr.,=to lie hidden], metallic chemical element; symbol La; at. no. 57; at. wt. 138.90547; m.p. about 920℃; b.p. about 3,460℃; sp. gr. 6.19 at 25℃; valence +3. Lan...

rubidium

(Encyclopedia)rubidium ro͞obĭdˈēəm [key], metallic chemical element; symbol Rb; at. no. 37; at. wt. 85.4678; m.p. 38.89℃; b.p. 686℃; sp. gr. 1.53 at 20℃; valence +1. Rubidium is a very soft silver-white ...

germanium

(Encyclopedia)germanium jərmāˈnēəm [key] [from Germany], semimetallic chemical element; symbol Ge; at. no. 32; at. wt. 72.63; m.p. 937.4℃; b.p. 2,830℃; sp. gr. 5.323 at 25℃; valence +2 or +4. Pure german...