It was only by very gradual degrees that the trabeated mode of roofing and spanning was succeeded by what is known as the arcuated, or that in which the arch takes the place of the horizontal beam. In early Roman temples and palaces the Greek style was long carefully copied, but in utilitarian works such as bridges, viaducts, and drains the arch was employed at a very remote period. An arch whether circular or pointed consists of two series of stones cut into the form of wedges known as voussoirs, a central one at the apex or highest point called the keystone locking the two series together. This beautiful contrivance, the inventor of which is unknown, gradually revolutionised the science of architecture. It was used at first, tentatively as it were, in combination with the horizontal beam or slab of stone, but in the end became in its rounded form the distinctive peculiarity of the Romanesque and in its pointed shape of the Gothic style.
ARCHITECTURE
CHAPTER I
EGYPTIAN, ASIATIC, AND EARLY AMERICAN ARCHITECTURE
The most ancient existing examples of Egyptian architecture are the royal tombs of the Memphite kingdom known as the Pyramids, of which the oldest is that of King Seneferu (about 3000 B.C.) at Medum, and the largest, which rises to a height of 481 feet from a base 764 feet square, that called the Great Pyramid of King Cheops (3788-3666) at Ghizeh, near Cairo, on which 100,000 men are said to have been continuously employed for thirty years. The latter is not only a marvel of constructive skill, but is by many authorities considered to be a most accurately designed astronomical observatory.
The Pyramids consist of masses of admirably squared and polished stones, in certain cases supplemented with bricks piled up in the form of a rectangle around a sepulchral chamber, the entrance to which was most carefully concealed. When the body of the monarch had been placed in it the tapering mound above it was finished off with huge facing blocks, that were skilfully worked into the angle required and finally levelled to a smooth surface.
Near the Pyramids of the kings are the tombs, known as Mastabas, of their wives and children and of the great officers of state. They are constructed of stone, are square or oblong in form, and their walls are adorned with paintings of scenes from contemporary life, the whole reminiscent of earlier timber structures. Later tombs are those hewn out of the living rock at Beni Hassan and elsewhere, dating from about 2500 B.C., with porticoes upheld by columns resembling those of Greek temples and flat or curved roofs, the latter suggestive of the principle of the arch having been known to those who excavated them.
It was between 1600 B.C. and 1110 B.C. that the Egyptians reached their highest point of civilisation, and it was during that period that were erected the magnificent Theban temples, of which those at Karnak and Luxor, which were connected by an avenue of colossal sphinxes, are the finest still remaining. The plan of all Egyptian temples of whatever size was the same: a horizontal gateway flanked on either side by masses of masonry of considerably greater height than it, known as pylons, their surfaces enriched with symbolic carvings, giving access to a square space open to the sky, and partly surrounded with cloisters, leading into a noble hall of huge dimensions, its flat roof upheld by columns, some with capitals resembling lotus buds, others representing the head of the goddess Isis. Beyond this hall were a number of small dark rooms, the use of which has never been ascertained, enclosing within them the nucleus of the whole, the low narrow mysterious cell or sanctuary in which was enshrined the image of the god to whom the temple was dedicated. Outside these noble buildings were ranged obelisks, or four-sided tapering-pillars of great height, covered with hieroglyphics commemorating the triumphs of the kings, and colossal figures, few of which remain in situ, which added greatly to the dignity of the appearance of the whole.