Nägeli, Karl Wilhelm Von

Nägeli received his earliest training from the German nature-philosopher Lorenz Oken and later studied botany under Augustin Pyrame de Candolle at the University of Geneva. He continued his botanical studies under Matthias Jakob Schleiden at the University of Jena and began

Ligand

In chemistry, any atom or molecule attached to a central atom, usually a metallic element, in a coordination or complex compound. The atoms and molecules used as ligands are almost always those that are capable of functioning as the electron-pair donor in the electron-pair bond (a coordinate covalent bond) formed with the metal atom. Examples of common ligands are the

Decroly, Ovide

Belgian pioneer in the education of handicapped and normal children. He was a physician who became involved in a school for abnormal children and consequently became interested in education. One outcome of this interest was his establishment in 1901 of the Institute for Abnormal Children in Uccle, Belg., a school that provided a homelike

Apurímac River

Spanish  Río Apurímac,   river in southern Peru. Owing to its lengthy Andean tributaries, it is the farthermost source of the Amazon River. Arising at roughly 17,000 feet (5,200 m) from the snowmelts of Mount Mismi in Arequipa departamento, Peru, it flows northwest through the Andes, descending to less than 860 feet (260 m) to join the Urubamba and form the Ucayali River. For most of its 430-mile (700-kilometre) length, it flows

China, Confucianism

Confucianism was perceived by the Mongols as a Chinese religion, and it had mixed fortunes under their rule. The teachings of the Neo-Confucian school of Chu Hsi from the Sung period were introduced to the Mongol court at Chung-tu in the late 1230s but were confined to limited circles there and in North China. Confucian scholars enjoyed the benefits extended to the clergy

Rub' Al-khali

Also spelled  Ar-Rab' al-Khali (Arabic: “Empty Quarter”)  vast desert in the southern Arabian Peninsula, covering about 250,000 square miles (650,000 square km) in a structural basin lying mainly in southeastern Saudi Arabia, with lesser portions in Yemen, Oman, and the United Arab Emirates. It is the largest area of continuous sand in the world. It occupies more than one-quarter of Saudi Arabia. The topography is varied. In the west the elevation

Pabst, G.w.

In full  Georg Wilhelm Pabst  German film director whose films were among the most artistically successful of the 1920s. Pabst's films are marked by social and political concerns, deep psychological insight, memorable female protagonists, and human conflicts with culture and society. He is also noted for

Yogurt

Also spelled  Yoghurt, Yourt, or Yoghourt,   semifluid fermented milk food having a smooth texture and mildly sour flavour because of its lactic acid content. Yogurt may be made from the milk of cows, sheep, goats, or water buffalo. Cow's milk is used in the United States and north-central Europe; sheep's and goat's milk are preferred in Turkey and southeastern Europe; milk from the water buffalo is most commonly used

Refractory

Any material that has an unusually high melting point and that maintains its structural properties at very high temperatures. Composed principally of ceramics, refractories are employed in great quantities in the metallurgical, glassmaking, and ceramics industries, where they are formed into a variety of shapes to line the interiors of furnaces, kilns, and other

Jackson, Howell E.

Jackson practiced law in the towns of Jackson and Memphis, Tenn., until the outbreak of the American Civil War, during which he served the Confederacy as a receiver of sequestered property. He gained prominence in his practice after the war and in 1880 was