Cuyuni
a river of South America, rises in Venezuela, flows first N., then E. through British Guiana, and joins the Mazaruni just above the confluence of the latter with the Essequibo. It has numerous rapids and falls; the lowest is CUZCO at 59° 3′ W., about 30 miles above the mouth of the river.
CUZCO (köz'ka), an inland city of Peru, capital of a department of same name (area, 156,270 square miles; pop. about 500,000), and formerly capital of the empire of the Incas, at the foot of some hills, 11,380 feet above the level of the sea, about 400 miles E. S. E of Lima. According to tradition, this town was founded in 1043, by Manco Capac, the first Inca of Peru. The grandeur and magnificence of the edifices, es, of its fortress, and of the Temple of the Sun, struck the Spaniards with astonishment in 1534, when the city was taken by Francis Pizarro. On the hill toward the north are yet seen the ruins of a fortress built by the Incas. Pop. about 15,000.
CYANAMID. NC.NH2, formed by the action of ammonia on cyanogen chloride. The name is also applied to the compound calcium, Cyanamid NC.NCa, an important product formed in the fixation of atmospheric nitrogen by the socalled "cyanamid process." Calcium is first produced by heating carbon and calcium at high temperatures in an electric furnace, and this compound is then heated under pressure with nitrogen obtained from the air. The crude product, known also as Nitrolim, is used as a fertilizer and undergoes decomposition in the soil with the production of cyanamid. The latter is then converted to urea, which is hydrolyzed to ammonium carbonate by organisms in the soil (q. v. NITROGEN).