and of hewn stone ; their proportions apt and grand. The portals especially are often decorated with intricate carving ; so also is the prayer-niche within, that indicates the direction of the Meccan Kibleh. These buildings, with their belongings, are works of charity, and are supported, repaired, and so forth, out of funds derived from pious legacies, most often of land or rentals Sometimes a municipality takes on itself to construct and maintain a caravanserai; but in any case the institution is registered as tax-free, and its revenues as inalienable. When, as sometimes happens, those revenues have been dissipated by peculation, neglect, or change of times, the caravanserai passes through downward stages of dilapidation to total ruin (of which only too many examples may be seen by the Eastern traveller), unless some new charity intervene to repair and renew it. In the general decline of wealth, public spirit, and prosperity actually prevailing throughout the Mahometan Levant, such better fortune is, however, rare. " Khans," or places more analogous to our own town-inns and hotels, where not lodging only, but often food and other necessaries or comforts may be had for payment, are sometimes by inaccurate writers confounded with caravanserais, though having really nothing in com mon with them, except that they are also for the use of travellers. These " Khans " are generally to be found within the town or village precincts, aud are of much smaller dimensions than caravanserais. The "Khan" called that of Asaad Pasha at Damascus is a model of con
structive skill and architectual beauty.CARAVELLAS, a seaport town of Brazil, in the province of Espiritu Santo, on a river, and not far from a bay, to which it gives its name, in 17 49 S. lat. and 39 26 W. long. It is the principal port of the neighbouring country, and serves as the headquarters of the whale fishery of the Abrolhos Islands which lie off the coast. Population, about 5000.
CARAWAY, the fruit, or so-called seed, of Carum carui, an umbelliferous plant growing throughout the northern and central parts of Europe and Asia. The plant has finely-cut leaves and compound umbels, and fruits laterally compressed and ovate, the mericarps being subcylindrical, slightly arched, and marked with five distinct pale ridges. Caraways evolve a pleasant aromatic odour when bruised, and they have an agreeable spicy taste. They yield from 3 to 6 per cent, of a volatile oil, which is a compound of carvol (a mobile liquid isomeric with the menthol of spearmint) aud carvene. The plant is cultivated in the northern parts of Norway, in Finland, Russia, Germany, Holland, and in Marocco, as well as in the south of England, the produce of more northerly latitudes being richer in essential oil than that grown in southern regions. The essential oil is largely obtained by distillation for use in medicine as an aromatic stimulant and carminative, and as a flavouring material in cookery and in liqueurs for drinking. Caraways are, however, more extensively consumed entire in certain kinds of cheese, cakes, and bread, and they form the basis of a popular article of confectionery known as caraway comfits.
CARBOLIC ACID, or Phenol (C rI 6 O), an acid su 1 stance forming one of ths numerous constituents of coal-tar, was first described by Runge in 1834. Its con stitution was investigated by Laurent in 1841, who, regard ing it as a hydrated oxide of the compound radical phenyl, termed it the hydrate of phenyl. Among other names it has received are phenic acid, phenyl alcohol, and creosote ; but though the latter is popularly applied to an impure mixtare of carbolic acid and the allied cresylic acid, it properly belongs to an altogether distinct substance. In addition to being an abundant constituent of coal-tar, carbolic acid is formed by the action of heat upon salicylic acid ; it can be obtained by the dry distillation of gum- benzoin and other resinous substances ; traces of it are found in the urine of the horse, the ox, and man ; and to it castoreum owes its peculiar odour.
Commercial carbolic acid is prepared solely from coal- tar by a method of which the following is an outline. When coal-tar is distilled the most volatile products benzol, toluol, cumol, &c., first come away, after which when the temperature rises from 150 C. to 200 C. crude carbolic acid distils over. This distillate is mixed with a strong solution of caustic potash, and the resulting carbolate of potash is in its turn treated with sulphuric acid, which decomposes the carbolate, liberating carbolic acid, which rises to the surface as an oily layer, and is removed by a syphon. The product is purified by washing and repeated rectification, and finally cooled down to 10 C., when it forms whitish acicular crystals, from which the unsolidified acid is drained away. Crystallized carbolic acid of com merce retains a strong naphthalic odour, from which it may be freed for medicinal or other purposes by a method recom mended by Professor Church. Into 1 B> of the crystal lized acid he pours 20 & of cold distilled water, care being taken that the whole of the acid shall not be dissolved. The mixture is repeatedly shaken till from 2 to 3 ounces of the acid only remains undissolved, in which residue the whole of the impurities are retained. From this, the aqueous solution is syphoned off, and if necessary, filtered, and then pure powdered common salt is added to it till the salt will no longer dissolve. After standing some time the whole of the carbolic acid rises to the surface, and floats as a yellow oily layer, which as it contains 5 per cent, of water will not crystallize. It may be crystallized by distilling from a little lime, and the product collected up to 185 C. will possess only a faint pleasant aromatic odour. Pure carbolic acid crystallizes in long colourless needles; it melts at 35 C., and boils about 187 C. It is soluble in all proportions in alcohol, ether, and strong acetic acid, but dissolves only sparingly in water. It does not redden litmus paper; it exerts a powerful corrosive action on the skin ; its aqueous solution coagulates albumen ; and it unites with animal substances, preserving them from decomposition, and removing, the offensive odour from putrefying matter.
The extensive manufacture and employment of carbolic acid are, in a large degree, owing to the exertions of the late Professor Grace Calvert, who was the first to manufac ture it in the crystalline form. The development of the aniline colour industry also communicated an impetus to the manufacture of carbolic acid, as the one is, in a sense, a secondary product of the other. A great many useful applications have opened up for the employment of the acid in addition to its extensive medicinal and antiseptic uses (see Antiseptics). For domestic, sanitary, and medicinal use, carbolic acid is prepared in various states of purity and strength. Toilet and medicated soaps, tooth powder, disinfecting powder, <fcc., are all prepared containing definite proportions of the acid. A Sarge quantity of crude carbolic acid is employed under the name of creosote for impregnating wood for railway sleepers and piles, and for engineering purposes generally, a method of preserving wood discovered and patented by Mr John Bethell.
preparation of several dyeing materials, which are second only in importance to the colours derived from aniline. Picric or carbazotic acid is a brilliant yellow dye-stuff, much used for wool and silk dyeing, prepared by very cautiously adding in Small quantities nitric acid to crystallized carbolic acid, or to a mixture of carbolic acid with sulphuric acid.
From picric acid in its turn two derivatives are obtained.
