PYRAMID, a structure of the shape of the geometric figure so called, erected in different parts of the old and new world, the most important being the pyramids of Egypt and Mexico. Those of Egypt were considered one of the seven wonders of the world, are 70 in number, of different sizes, are between 29° and 30° n. lat.:and are masses of stone or brick, with square bases, and triangular sides. Although various opinions have prevailed as to their use, as that they were erected for astronomical purposes, for resisting the encroachment of the sand of the desert, for granaries, reservoirs, or sepulchers, the last-mentioned hypothesis has been proved to be correct in recent times by the excavations of the late gen. Howard Vyse, who is said to have expended nearly £10,000 in investigating their object and structure. They were all the tombs of mon archs of Egypt who flourished from the fourth to the twelfth dynasty, none having been constructed later than that time; the subsequent kings being buried at Abydos, Thebes. and other places, in tombs of a very different construction. The meaning of the word pyramid is involved in great obscurity; although attempts have been made to derive it from the Coptic piharam, yet, as in the hieroglyphs, it is found in connection with the words ben ben or ber ber, forms of the Coptic beebe mahou, or tomb, and abmer, or sepulcher, it is probably an ancient Greek word. The pyramids are solid mounds raised over the sepulchral chambers of the kings, the first act of an Egyptian monarch being to prepare his future " eternal abode." For this purpose, a shaft of the size of the intended sarcophagus was first hollowed in the rock at a suitable incline to lower it, and at a convenient depth a rectangular chamber was excavated in the solid rock. Over this chamber a cubical mass of masonry, of square blocks, was then placed, leaving the orifice of the shaft open. Additions continued to be made to this cubical mass both in height and breadth as long as the monarch lived, so that at his death all that remained to be done was to face or smooth the exterior of the step-formed mound. But in some eases the masonry passed beyond the orifice of the shaft, which involved the construe tion of a new shaft, having its orifice beyond it. The pyramid was faced by adding courses of long blocks on each layer of the steps, and then cutting the whole to a flat or even surface, commencing from the summit. The outer masonry, however, or casing, as it is called, has in most instances been partially stripped off. Provision was made for protecting the vertical joints by placing each stone half way over another. The masonry is admirably finished; and the mechanical means by which such immense masses of stone were raised to their places has long been a mystery; the discovery, how ever, of large circular holes in some of the stones has led to the conclusion that they were wound up by machines. The stones were quarried on the spot; sometimes, how ever, granite taken from the quarries of Syene was partially employed. The entrances were carefully filled up, and the passage protected by stone portcullises and other contri vances, to prevent ingress to the sepulchral chamber. There appears to have been also a door or pylon at the entrance of the shaft, ornamented with Egyptian sculptures and hieroglyphs. The sides of the pyramids face the cardinal points, and the entrances face the north. The work of the larger pyramids was executed by corvees of laborers. The most remarkable and finest pyramids are those of Gizeh, situated on a level space of the Libyan chain at Memphis, on the w. bank of the Nile. The three largest are the most famous.
The first or Great Pyramid, as appears from the excavations of Vyse, was the sepulchre of the Cheops of Herodotus, the Cliembes, or Chemmis, of Diodorus, and the Suphis of Manetho and Eratosthenes. Its height was 480 ft. 9 in., and its base 764 ft. square; in other words, it was higher than St. Paul's cathedral, on an area the size of Lincoln's Inn Fields. Its slope or angle was 51° 50'. It has been, however, much spoiled and stripped of its exterior blocks for the building of Cairo. The original sepulchral chamber, called the subterranean apartment, 46 ft. X 27 ft., and 11 ft. 6 in. high, has been hewn in the solid rock, and was reached by the original passage of 320 ft. long, which descended to it by an entrance at the foot of the pyramid. The excavations in this direction were subsequently abandoned, on account of the vast size attained by the pyramid, which rendered it impracticable to carry on the entrance on a level with the natural rock, which had been cut down and faced for that purpose. Accordingly, a second chamber, with a triangular roof, was constructed in the masonry of the pyramid, 17 ft. X 18 ft. 9 in., and 20 ft. 3 in. high. This was reached by a passage rising at an inclination of 26° 18', terminating in a horizontal passage. It is called the queen's chamber, and occupies a position nearly in the center of the pyramid. The monument —probably owing to the long life attained by the monarch—still progressing, a third chamber, called the king's, was finally constructed, by prolonging the ascending passage of the queen's chamber for 150 ft. further into the very center of the pyramid, and after a short horizontal passage, making a room 17 ft. 1 in. X 34 ft. 3 in., and 19 ft. 1 in. high. To diminish, however, the pressure of the superincumbent masonry on the flat roof, 5 small chambers were made vertically in succession above the roof, the last one pointed, varying in height from 1 ft. 4 in. to 8 ft. 7 in., the apex of the top one being rather more than 69 ft. above the roof of the king's chamber. The end of the horizontal passage was finished in a superior style, and cased with red Syenitic granite; and in the king's chamber was the granite sarcophagus of the king Cheops, 7 ft. 61 in. long, 3 ft. 3 in. broad, and 3 ft. 5 in. high, for whom the pyramid was built.* As the heat of this chamber was stifling, owing to want of ventilation, two small air-channels, or chimneys about 9 in. square, were made, ascending to the n. and s. sides of the pyramid. They perfectly ventilate this chamber. After the mummy was deposited in the king's cham ber, the entrance was closed with granite portcullises, and a well made at the junction of the upward-inclined and horizontal passages, by which the workmen descended into the downward-inclined passage, after carefully closing the access to the sepulchral chambers. The changes which took place in this pyramid gave rise to various traditions, even in the days of Herodotus, Cheops being reported to lie buried in a chamber sur rounded by the waters of the Nile. It took a long time for its construction-100,000 men being employed on it for 30 years, or more probably for above half a century, the dura tion of the reign of Cheops, which is dated by different chronologists at 3,229, 3,095, or 2.123 B. c. The operations in this pyramid by gen. Vyse gave rise to the discovery of marks scrawled in red ocher in a kind of cursive hieroglyphs on the blocks brought from the quarries of Tourah. These contained the name and titles of Khufu (the hiero glyphic form of Cheops); numerals and directions for the position of materials: with them were masonic marks.