CTJZA. 699 CYANOGEN. CTTZA, koo'zi. See Alexander John I. CUZCO, koos'kd, Castiliuii Sp. pron. kooth'kfl (Quichua, navel, as being the centre of the an- cient Inca Empire). An eiiiscopal citj', the capi- tal of the department of the same name, I'eru, situated on the eastern end of that section of the Andes known as the Knot of Cuzco, 11,000 feet above sea-level, and 528 miles southeast of Lima (ilap: Peru, C (i). It is regularly built in part, and contains several handsome build- ings, prominent among wliioh is the Cathedral of Santo Domingo, in the Corinthian style. There are also hospitals, a university founded in 1G92, a national college, and a museum. The city is the centre of a fertile agricultural district, and has considerable trade and manufactures of cot- ton and woolen goods, refined sugar, leather, and embroidery. Population, about 30,000. Cuzco. the capital of the Incas, is said to have been founded in the eleventh century. It retains evidences of its former splendor, although the ancient city was destroyed by Pizarro in 1535. These remains include the palace of the Incas, a fortress built of massive and irregular stone blocks, the temple of the Sun, and the temple of the virgins of the Sun. CUZCO. One of the largest departments of Peru, bounded by Lorcto on the north, Bolivia on the east, Puno and Arequipa on the south, and Apurimae, Ayacucho, and Junin on the west (ilap: Peru, C G). Area estimated at over 156,000 square miles. The southern and west- ern parts are mountainous, and the eastern and northern are low and covered with thick forests. The department is to a large extent imexplored, and onlj' a small portion in the south is inhabited. It is watered by the Urabamba and the headstreams of many tributaries of the Amazon. The population is chiefly engaged in agriculture and cattle-raising. Population, offi- cially estimated in 1896 at 438,646. Capital, Cuzco (q.v.). CYAM'ELIDE. See Ctamc Acid; Wohusb. CYANE, si'ane (Lat., from Gk. Krai';?, Ky- ane) . In Greek legend, the wife of .Eolus, the god of the winds. Also a n3-mph, playmate of Persephone. She was transformed into the spring Cyane near Syracuse at the time when Hades carried oft" Persephone from this neighbor- hood. CYANIC ACID (from Gk. Kiamg, kyanos, dark-blue). An unstable compound of carbon, hydrogen, oxygen, and nitrogen, obtained by heating cyanuric acid (q.v.) in a current of car- bon dioxide. Under ordinary conditions it is a volatile liquid having a strong pungent odor, but is readily transformed into a white, porcelain- like mass of the same percentage composition as cyanic acid, though probably of much higher molecular weight. This polymeric modification of cyanic acid is laiown as cyamelidc. (See WotiLER. ) Among the salts of cyanic acid may be mentioned the cyanate of potassium and the cyanate of annnonium. Potassium cyanate may be readily obtained by cautiously heating a mix- ture of potassium ferrocyanide and potassium bichromate; when pure it forms a white crystal- line powder readily soluble in water, in which, however, it gradually undergoes decomposition. Ammonium cyanate may be obtained from the cyanate of potassium by double decomposition. The transformation of ammonium cyanate into Vol. v.— 45. urea, observed by Wolilcr in 1828, constituted the first synthesis of an organic compound and formed an event of the greatest importance in the history of chemistry. The careful study to which many derivatives of cyanic acid have been subjected has led to the view that cyanic acid may jiossess two dill'crcnt constitutional formulas, viz. X = C — O — II and O = C =: N — H. All cll'orts to produce two dif- ferent compounds corresponding to those formu- las having failed, chemists have proposed to ex- plain this comparatively rare phenomenon on the following hypotheses: (1) Cj-anic acid, like most other organic compounds, has a definite structure — say X= C — O — 11; but while, dur- ing some of its transformations, that structure re- mains unaltered, other trausf(irmations involve an intramolecular change resulting in the forma- tion of derivatives of the compound = C = N — H ('iso-cyanic acid'), which is, for some un- known reason, less stable than the compound N S C — O — H and incapable of existing in the free state. (2) According to another hypothesis, every single molecule of the acid is constantly changing its structure, its hydrogen atom rap- idly oscillating between the nitrogen and the oxygen ; so that while at a given instant the structure of the molecule might be represented by the fornnila N= C — O — H. we would find its structure to be O = C = N — H if we could stop the motion of the hydrogen atom at the very next instant. The substance is thus iuuigincd to be composed, at any instant, of two diii'crent kinds of molecules; and as under certain conditions each kind may be capable of transformations which the other kind could not undergo, two series of derivatives should be expected, accord- ing to the nature of the transformations neces- sary to produce those derivatives and to the conditions under ^hieh the transformations take place. CY'ANIDES. See Htdbocyanic Acid. CY'ANITE (from Gk. Kuoi/of, kyanos, dark- blue), Ky.mte. Distiiene, or Sappabe. An aluminum silicate that crystallizes in the tri- clinic system. Although sometimes gray or green, it usually has a blue color and a vitreous to pearly lustre. The handsomest specimens are found in the Saint Gothard region in Switzer- land : in the United States, Chesterfield. Mass., and Bakersfield, X. C, are well-known localities. Fine specimens have been cut as gems, but as a rule the material is too soft for wear. CYAN'OGEN (Gk. Kvamc, kyanos, dark- blue + 7^>"js, genes, producing, from ylypfaSai, gignesthai, Lat. gignere, Skt. jan, to be born). An important compound of carbon and nitrogen obtained by heating dry cyanide of mercur.y in hard glass tubes, it is a poisonous gas* having a peculiar odor and dissolving quite readil.v in water and in alcohol. If ignited in air it burns with a purple flame, its carbon combining with the o.vvgen of the air to form carbon dioxide, while its nitrogen is set free. When dry, cyan- ogen is an exceedingly stable substance and may be heated as high as 800° C. without being de- composed; in aqueous solution, however, it grad- uallv undergoes a series of chemical changes resulting in the formation of ammonia, hydro- cvanic acid, urea, oxalic acid, and other com- pounds. The molecular formula of cyanogen is C^2> its molecule being composed of two 'cyan-
