Columbia Encyclopedia

(Encyclopedia) echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...

(Encyclopedia) Kyushu kyo͞oˈsho͞o [key], island (1990 pop. 13,064,955), c.13,760 sq mi (35,640 sq km), S Japan. It is the third largest, southernmost, and most densely populated of the major islands of Japan. It ...

(Encyclopedia) Qingdao tsĭngˈtouˈ, chĭngˈdouˈ [key], city (1994 est. pop. 1,584,100), SE Shandong prov., E China, on the Yellow Sea. With an excellent ice-free harbor, it is a major fishing and trade port of C...

(Encyclopedia) chalk, mineral of calcium carbonate, similar in composition to limestone, but softer. It is characteristically a marine formation and sometimes occurs in great thickness; the chief constituents of the...

(Encyclopedia) Lake Charles, city (1990 pop. 70,580), seat of Calcasieu parish, SW La.; inc. 1867. It is located on Lake Charles at the mouth of the Calcasieu River in a rice, timber, oil, and natural gas region. Th...

(Encyclopedia) MacCready, Paul Beattie, 1925–2007, American engineer and inventor known for his achievements in human-powered flight, b. New Haven, Conn., Ph.D. California Institute of Technology, 1952. In 1997 he...

(Encyclopedia) Avon āˈvən, ăvˈən [key] [Celtic,=river], name of several rivers in England. 1 Also called Bristol Avon or Lower Avon, rising in SW England at Tetbury, Gloucestershire, and flowing 75 mi (121 km)...

(Encyclopedia) Picardy pĭkˈərdē [key], Fr. Picardie, region and former province, N France, on the English Channel, part of the French administrative region of Hauts-de-France. It includes the Somme, Oise, and Ai...

(Encyclopedia) Central Valley project, central Calif., long-term general scheme for the utilization of the water of the Sacramento River basin in the north for the benefit of the farmlands of the San Joaquin Valley ...

(Encyclopedia) Chicago, river, formed in Chicago by the junction of its North Branch (24 mi/39 km long) and South Branch (10 mi/16 km long), and flowing southeast via a canal into the Des Plaines River at Lockport, ...