CARACCI
332
CARBONIC ACID
through the port of La Guaira; also cocoa, caoutchouc, ornamental feathers and furniture woods. Population, 75,000.
Caracci (kdr-rdfch&) or Carracci, a celebrated family of Italian painters, the founders of what is called the Bolognese school of painting, which nourished in the latter halt of the i6th century. LUDOVICO CARACCI, son of a butcher, was so poor a student that his masters advised him to give up painting. Instead of following their advice, ne went to Parma and Venice, and there studied the works of the great masters, and came back filled with new ideas of his art quite different from the lifeless style of his native Bologna. With his two cousins, he started the eclectic school, which has become famous in the history of painting, and soon all other schools at Bologna were closed. Many of the works of this master are preserved at Bologna.
ANNIBALB CARACCI, a cousin of Ludovico, was, perhaps, the greatest artist of his family. He was born in 1560. He made rapid grogress in the study of painting, and his ime soon reached Rome, where he was employed to paint the Farnese gallery, his greatest work. He died at Rome in 1609, and was buried close to Raphael's tomb in the Pantheon. The best Italian masters of the 17th century were of the school of the Caracci.
Car7avails are bands of merchants, pilgrims or other travelers who journey in company through the desert. The name caravan is of Persian origin; the deserts of Asia and Africa are its home. Here travelers seek safety in numbers, as well for defense against robbers as for the sake of aiding one another amid other perils of the way, the chief of which are storms of dust and whirlwinds. The hot and sand-laden wind, called in the Sahara Desert the simoom, has been known to destroy a whole caravan by suffocation. Not seldom does a line of half-buried bones of camels and of men greet the eye of the desert voyager. In the case of caravans from Tibet to China, yaks, mules and horses are used rather than camels.
Large and famous are the annual caravans which convey pilgrims to Mecca from Persia and from Cairo in Egypt. Several thousands of pilgrims will sometimes journey to Mecca in a single caravan. The internal long-distance trade of Asia and Africa is almost wholly a caravan trade. The chief overland trade-route between Russia and China runs close to the Siberian Railroad from Moscow to Irkutsk and thence to Kiakhta and Urga. A vast quantity of cotton goes by caravan from Khiva to Orenburg. Persia relies greatly upon caravans, since, except for its Russian trade, it is but ill-supplied with railroads. In the hot season it is usual for the desert caravans to travel by night; but 'they keep to as
fixed a route as do ships at sea, as indeed the perils of their course are at least as great.
Car'bohy'drates (in plants), substances consisting of carbon and of hydrogen and oxygen in the proportion to form water, which are manufactured by green plants out of carbon dioxid and water in the presence of light. (See PHOTOSYNTHESIS.) Common illustrations of carbohydrates are sugar and starch.
Car'bon is one of the elements, and is the characteristic substance of plants and animals. It is found uncombined in the mineral, graphite or black lead, and in the pure, crystallized form in the diamond. Anthracite coal, charcoal, coke and lampblack are nearly pure forms of carbon. Soft coal and peat also contain much carbon. United with oxygen it is carbon dioxide or carbonic acid, a constituent of the atmosphere and of carbonates, of which calcium carbonate as limestone, marble, chalk and the earthy matter of corals and shells, as well as dolomite, are very abundant substances. With hydrogen, carbon forms marsh-gas and a great number of hydrocarbons, as those of petroleum and numerous coal-tar products. With hydrogen and oxygen it forms acetic acid and other organic acids, alcohol, oils, fats and the so-called carbohydrates, of which the sugars, starch and cellulose, important constituents of plants, are the best known. A great many very complicated carbon compounds occur in plants, and particularly in animals, in which (besides carbon, hydrogen and oxygen), nitrogen and sometimes sulphur and other elements are present. Carbon also unites with certain metals, and with iron it forms steel and cast-iron. Certain denser forms of carbon, such as retort-carbon from gas-works and petroleum-refining, conduct electricity well, and are extensively used in batteries and electric lamps. See CHARCOAL, CHEMISTRY, DIAMOND and ELECTRIC LIGHT.
H. L. WELLS.
Car'bondale, a city of Pennsylvania, noted for the mines in its neighborhood, is on the Lackawanna River, 16 miles northeast of Scranton. It is the chief town of Lackawanna County, and its railroad facilities are furnished by the Delaware & Hudson; the New York, Ontario & Western; and the New York, Erie & Western railroad. The mines of the region are worked by the Delaware and Hudson Canal Company, and yield over a million tons annually. The city's industries have as their motive power abundant electrical* and other facilities, derived chiefly from the great adjacent coal-fields. Population, 17,040.
Carbon'ic Acid or carbon dioxid, also called fixed air or choke-damp, is a gas which forms about ^Vo- Par"t of "the air.
