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thymine

(Encyclopedia)thymine thīˈmēn [key], organic base of the pyrimidine family. Thymine was the first pyrimidine to be purified from a natural source, having been isolated from calf thymus and beef spleen in 1893–...

uracil

(Encyclopedia)uracil yo͝orˈəsĭl [key], organic base of the pyrimidine family. It was isolated from herring sperm and also produced in a laboratory in 1900–1901. When combined with the sugar ribose in a glycos...

oxide

(Encyclopedia)oxide, chemical compound containing oxygen and one other chemical element. Oxides are widely and abundantly distributed in nature. Water is the oxide of hydrogen. Silicon dioxide is the major componen...

fireproofing

(Encyclopedia)fireproofing, method of making normally combustible materials as nearly noncombustible as possible. Fireproofing generally applies to textiles and construction materials that are treated with a soluti...

Head, Bessie

(Encyclopedia)Head, Bessie, 1937–86, South African writer. Born in South Africa to a white mother and black father, she was placed in foster homes and orphanages as a child. After 1964, she lived in exile in Bots...

Cameroon, Mount

(Encyclopedia)Cameroon, Mount kămˈəro͞on [key], active volcano, 13,354 ft (4,070 m) high, in the Cameroon Highlands, W Cameroon; highest point in W Africa. The mountain and surrounding area are in Mt. Cameroon ...

Pindus

(Encyclopedia)Pindus pĭnˈdəs [key], Gr. Píndhos, chief mountain range of Greece, extending c.100 mi (160 km) S from the Albanian border through NW Greece. Mt. Smólikas (8,650 ft/2,637 m) is the highest peak. T...

chyme

(Encyclopedia)chyme kīm [key], semiliquid substance found in the stomach and resulting from the partial digestion of food by the salivary enzyme amylase, the gastric enzyme pepsin, and hydrochloric acid. Secretion...

sodium nitrate

(Encyclopedia)sodium nitrate, chemical compound, NaNO3, a colorless, odorless crystalline compound that closely resembles potassium nitrate (saltpeter or niter) in appearance and chemical properties. It is soluble ...

hay, livestock fodder

(Encyclopedia)hay, wild or cultivated plants, chiefly grasses and legumes, mown and dried for use as livestock fodder. Hay is an important factor in cattle raising and is one of the leading crops of the United Stat...