Earth

More than 90 percent of the Earth's mass is composed of iron, oxygen, silicon, and magnesium, elements that can form the crystalline minerals known as silicates. However, in terms of chemical and mineralogical composition, as in physical properties, the Earth is far from homogeneous. Apart from the superficial lateral heterogeneities near the surface (i.e., in the compositions

Raymond Vi

The son of Count Raymond V, Raymond VI was a nephew of King Louis VII of France and brother-in-law of King Richard I of England. Tolerant toward the many

Samarra'

Town, central Iraq. Located on the Tigris River, it is the site of a prehistoric settlement of the 5th millennium BC. The town was founded between the 3rd and 7th centuries AD. In 836, when the 'Abbasid caliph al-Mu'tasim was pressured to leave Baghdad, he made Samarra' his new capital. He built a palace and gardens, and under his successors the town grew until it stretched along the Tigris for

Kaministiquia River

Also spelled  Kaministikwia,  river, western Ontario, Can. It rises in Dog Lake and, after a crooked course of 60 miles (95 km), empties into Thunder Bay, an arm of Lake Superior. It has many rapids and cataracts, notably the wide Kakabeka Falls (154 feet [47 m] high), site of a major hydroelectric station. The river divides into three channels as it enters Thunder Bay, providing deepwater shipping docks at the city of Thunder

Hippocrateaceae

Family of woody vines, shrubs, and trees, belonging to the order Celastrales, comprising 21 genera common in the tropics. They have simple leaves and small, greenish flowers. The genus Hippocratea has 80 or more species, including H. ovata, a high-climbing vine—in tropical America and the West Indies—with leathery, oval leaves. Salacia, with 200 species, differs from Hippocratea

Algeria, World War II and the movement for independence

World War II brought with it the collapse of France and, in 1942, the Anglo-American occupation of North Africa. The occupation forces were to some extent automatically agents of emancipation; both Allied and Axis radio stations began to broadcast in Arabic, promising a new world for formerly subject peoples. The effect was further heightened by the June 1941 promise of emancipation

Empoli

Town, Firenze (Florence) provincia, Toscana (Tuscany) regione, north-central Italy, on the lower Arno River. During the medieval Florentine wars, Empoli was the scene of the Ghibelline congress of 1260, where Farinata degli Uberti successfully opposed the destruction of defeated Florence, an episode referred to in Dante's Inferno. The painter Iacopo Chimenti da Empoli and