CARLSBAD, or Kaiser-Karlsbad (Czech, Karlovy Vary), a town and celebrated watering-place of Bohemia, Austria, 116 m. W.N.W. of Prague by rail. Pop. (1900) 14,640. It is situated at an altitude of 1227 ft. and lies in the beautiful narrow and winding valley of the Tepl at its junction with the Eger, being hemmed in by precipitous granite hills, covered with magnificent forests of pine. The town is spread on both banks of the river and in the valley of the Eger, its houses being built up the mountain sides in tier above tier of terraces approached by long flights of steps or steep and tortuous roads. This irregularity of site and plan, together with the varied form and high-pitched roofs of the houses, makes the place very picturesque. Among the principal buildings of Carlsbad are the Catholic parish church, built in 1732–1736 in rococo style; the gorgeous Russian church, finished in 1897; the English church; and a handsome synagogue. In the first rank of the other buildings stands the famous Mühlbrunnen Colonnade, erected between 1871 and 1878, which, with its 103 monolithic granite Corinthian columns, is a fine example of modern classical architecture; the Kurhaus (1865); the magnificent Kaiserbad, built in 1895 in the French Renaissance style, and several other bathing establishments; the Sprudel Colonnade, an imposing iron and glass structure, built in 1879, within which rises the Sprudel, the principal spring of Carlsbad; and several hospitals and hospices for poor patients. Both banks of the Tepl are provided with quais, planted with trees, which constitute the chief promenades of the centre of the town; and there are, besides, a municipal park and several public gardens.
The mineral springs, to which Carlsbad owes its fame, rise from beneath a very hard kind of rock, known as Sprudelschale or Sprudeldecke, beneath which it is believed that there exists a large common reservoir of the hot mineral water, known as the Sprudelkessel. Several artificial apertures in the rock have been made for the escape of the steam of this subterranean cauldron, which, owing to the incrustations deposited by the water, require to be cleared at regular intervals. Altogether there are seventeen warm springs, with a temperature varying from 164° F. to 107.7° F., and two cold ones. The oldest, best-known, and at the same time the most copious spring is the Sprudel, a hot geyser with a temperature of 164° F., which gushes up in jets of 1½ ft. thick to a height of about 3½ ft., and delivers about 405 gallons of water per minute. Other springs are the Mühlbrunnen, with a temperature of 121° F., which is after the Sprudel the most used spring; the Neubrunnen (138° F.); the Kaiser-Karl-Quelle (112° F.); the Theresienbrunnen (134° F.), &c. The warm springs belong to the class of alkaline-saline waters and have all the same chemical composition, varying only in their degree of temperature. The chemical composition of the Sprudel, taken to a thousand parts of water, is: 2.405 sulphate of soda, 1.298 bicarbonate of soda, 1.042 chloride of soda, 0.186 sulphate of potash, 0.166 bicarbonate of magnesia, 0.012 bicarbonate of lithium, and 0.966 carbonic acid gas. They contain also traces of arsenic, antimony, selenium, rubidium, tin and organic substances. The water is colourless and odourless, with a slightly acidulated and salt taste, and has a specific gravity of 1.0053 at 64.4° F. The waters are used both for drinking and bathing, and are very beneficent in cases of liver affections, biliary and renal calculi, diabetes, gout, rheumatism, and uric acid troubles. They are very powerful in their effect and must not be used except under medical direction, and during the cure, a carefully-regulated diet must be observed, coupled with a moderate amount of exercise in the open air. The number of visitors in 1901 was 51,454; in 1756 it was only 257; in 1828 it was 3713; and it attained 14,182 in 1869, and 34,396 in 1890.