Columbia Encyclopedia

(Encyclopedia) machine tool, power-operated tool used for finishing or shaping metal parts, especially parts of other machines. An establishment that is equipped with such tools and specializes in such work is known...

(Encyclopedia) Mount Wilson Observatory, astronomical observatory located in California on Mt. Wilson, near Pasadena. Mt. Wilson Observatory was founded in 1904 by George E. Hale. Its equipment includes 100-in. (2.5...

(Encyclopedia) stroke, destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other for...

(Encyclopedia) vulcanization vŭlˌkənəzāˈshən [key], treatment of rubber to give it certain qualities, e.g., strength, elasticity, and resistance to solvents, and to render it impervious to moderate heat and c...

(Encyclopedia) phosphate, salt or ester of phosphoric acid, H3PO4. Because phosphoric acid is tribasic (having three replaceable hydrogen atoms), it forms monophosphate, diphosphate, and triphosphate salts in which ...

(Encyclopedia) symmetry, biological, similarity or balance between parts of an organism so that when a straight cut is made through a point or along a line, equal, mirror-image halves are formed. Symmetry in body sh...

(Encyclopedia) Five-Year Plan, Soviet economic practice of planning to augment agricultural and industrial output by designated quotas for a limited period of usually five years. Nations other than the former USSR a...

(Encyclopedia) aspirin, acetyl derivative of salicylic acid (see salicylate) that is used to lower fever, relieve pain, reduce inflammation, and thin the blood. Common conditions treated with aspirin include headach...

(Encyclopedia) Reid, Whitelaw, 1837–1912, American journalist and diplomat, b. near Xenia, Ohio. His distinguished correspondence during the Civil War for the Cincinnati Gazette led Horace Greeley to make him mana...

(Encyclopedia) Kaunda, Kenneth David kounˈdə [key], 1924–2021, African political leader, president of Zambia ...