In consequence of its insanitary condition, Cairo used to have a heavy death-rate. Since the British occupation in 1882 much has been done to better this state of things, notably by a good water-supply and a proper system of drainage. The death-rate of the native population is about 35 per 1000. The climate of the city is generally healthy, with a mean temperature of about 68° F. Though rain seldom falls, exhalations from the river, especially when the flood has begun to subside, render the districts near the Nile damp during September, October and November, and in winter early morning fogs are not uncommon. The prevalent north wind and the rise of the water tend to keep the air cool in summer.
The commerce of Cairo, of considerable extent and variety, consists mainly in the transit of goods. Gum, ivory, hides, and ostrich feathers from the Sudan, cotton and sugar from Upper Egypt, indigo and shawls from India and Persia, sheep and tobacco from Asiatic Turkey, and European manufactures, such as machinery, hardware, cutlery, glass, and cotton and woollen goods, are the more important articles. The traffic in slaves ceased in 1877. In Bulak are several factories founded by Mehemet Ali for spinning, weaving and printing cotton, and a paper-mill established by the khedive Ismail in 1870. Various kinds of paper are manufactured, and especially a fine quality for use in the government offices. In the Island of Roda there is a sugar-refinery of considerable extent, founded in 1859, and principally managed by Englishmen. Silk goods, saltpetre, gunpowder, leather, etc., are also manufactured. An octroi duty of 9% ad valorem formerly levied on all food stuffs entering the city was abolished in 1903. It used to produce about £150,000 per annum.
Architecturally considered Cairo is still the most remarkable and characteristic of Arab cities. The edifices raised by the Moorish kings of Spain and the Moslem rulers of India may have been more splendid in their materials, and more elaborate in their details; the houses of the great men of Damascus may be more costly than were those of the Mameluke beys; but for purity of taste and elegance of design both are far excelled by many of the mosques and houses of Cairo. These mosques have suffered much in the beauty of their appearance from the effects of time and neglect; but their colour has been often thus softened, and their outlines rendered the more picturesque. What is most to be admired in their style of architecture is its extraordinary freedom from restraint, shown in the wonderful variety of its forms, and the skill in design which has made the most intricate details to harmonize with grand outlines. Here the student may best learn the history of Arab art. Like its contemporary Gothic, it has three great periods, those of growth, maturity and decline. Of the first, the mosque of Ahmed Ibn-Tulun in the southern part of Cairo, and the three great gates of the city, the Bab-en-Nasr, Bab-el-Futuh and Bab-Zuwela, are splendid examples.
The design of these entrance gateways is extremely simple and massive, depending for their effect on the fine ashlar masonry in which they are built, the decoration being more or less confined to ornamental disks. The mosque of Tulun was built entirely in brick, and is the earliest instance of the employment of the pointed arch in Egypt. The curve of the arch turns in slightly below the springing, giving a horse-shoe shape. Built in brick, it was found necessary to give a more monumental appearance to the walls by a casing of stucco, which remains in fair preservation to the present day. This led to the enrichment of the archivolts and imposts with that peculiar type of conventional foliage which characterizes Mahommedan work, and which in this case was carried out by Coptic craftsmen. The attached angle-shafts of piers are found here for the first time, and their capitals are enriched, as also the frieze surmounting the walls, with other conventional patterns. The second period passes from the highest point to which this art attained to a luxuriance promising decay. The mosque of sultan Hasan, below the citadel, those of Muayyad and Kalaun, with the Barkukiya and the mosque of Barkuk in the cemetery of Kait Bey, are instances of the second and more matured style of the period.
The simple plain ashlar masonry still predominates, but the wall surface is broken up with sunk panels, sometimes with geometrical patterns in them. The principal characteristics of this second period are the magnificent portals, rising sometimes, as in the mosque of sultan Hasan, to 80 or 90 ft., with elaborate stalactite vaulting at the top, and the deep stalactite cornices which crown the summit of the building. The decoration of the interior consists of the casing of the walls with marble with enriched borders, and (about 20 ft. above the ground) friezes 3 to 5 ft. in height in which the precepts of the Koran are carved in relief, with a background of conventional foliage. Of the last style of this period the Ghuriya and the mosque of Kait Bey in his cemetery are beautiful specimens. They show an elongation of forms and an excess of decoration in which the florid qualities predominate. Of the age of decline the finest monument is the mosque of Mahommad Bey Abu-Dahab. The forms are now poor, though not lacking in grandeur, and the details are not as well adjusted as before, with a want of mastery of the most suitable decoration.
The usual plan of a congregational mosque is a large, square, open court, surrounded by arcades of which the chief, often several bays deep, and known as the Manksura, or prayer-chamber, faces Mecca (eastward), and has inside its outer wall a decorated niche to mark the direction of prayer. In the centre of the court is a fountain for ablutions, often surmounted by a dome, and in the prayer-chamber a pulpit and a desk for readers. When a mosque is also the founder's tomb, it has a richly ornamented sepulchral chamber always covered by a dome (see further Mosque, which contains plans of the mosques of Amr and sultan Hasan, and of the tomb mosque of Kait Bey).
After centuries of neglect efforts are now made to preserve the monuments of Arabic art, a commission with that object having been appointed in 1881. To this commission the government makes an annual grant of £4000. The careful and syste-matic work accomplished by this commission has preserved much of interest and beauty which would otherwise have gone utterly to ruin. Arrangements were made in 1902 for the systematic repair and preservation of Coptic monuments.