PYRAMID, the term applied to elevated mounds of stone or brick work of the geometrical. shape of that name, the most remarkable of which are those in the plain of Gizeb, which were considered one of the seven wonders of the ancient world. The origin of the name is involved in much obscurity ; but it appears, like obelisk, to be a Greek term, the hieroglyphic word for pyramid being pa abmer, ben ben, or ber bcr ; the Coptic piharam, and Arabic d haram, being derived from the Greek. These pyramids are sloped or symmetrical mounds placed over the graves or chambers of the sepulchres made for the monarchs and other great personages of the earliest Egyptian dynasties, commencing with the 3rd and ending with the 12th, after which their use was abandoned in Egypt. The pyramids lying in a vast plain or cemetery, extending from 29° to 30' N. lat., for between 60 and 70 miles, are supposed to be about 69 in number. They are all constructed in a uniform manner. A rectangular sepulchral chamber was first hollowed in the rock, with a passage of sufficient dimensions to admit the sarcophagus, communicating with the surface. Over this was at once erected a cubical course of masonry, which served for the nucleus of the pyramid. If the king died during the year, the masonry was covered with a polished casing in shape of a small pyra mid ; if the monarch survived, another course of masonry was added to the height of the nucleus, and the length of the lower stage or base increased by courses of stone on each side. Additions on the same plan continued to be made as as the king lived, fresh courses being added from year to year. the monarch died this ceased ; the pyramid was cased by filling up the angles of the masonry with smaller stones, placing oblong blocks one upon another, so as to make a series of steps from the top to the base, and then bevelling off all these stones, commencing from the top downwards, at a uniform angle. A smooth surface was given to each side of the pyramid, rendering it a perfect triangle, while, owing to each stone overlapping the other, no vertical joint was left. Some differences am observable as to the manner in which the internal walls were either vertical or inclined ; but the general principle is the same in all, and the mode of finishing the pyramid casings corresponds with the description of Iferodotus (Ii. cxxv.). The means by which the stones were raised is not known ; but the discovery of hemispherical holes about 8 inches in diameter, that look polished by the turning of a heavy body, have suggested the use of derricks, or similar machines—the employment of scallbiding for the purpose being impossible. All the pyramids are placed with their sides facing the four cardinal points of the compass, and their entrances are on the north side, somewhere about the cebtre. Extraordinary precautions were taken to prevent access to the sepel elms' chambers ; the passages, made exceedingly narrow, were closed by great blocks of stone or granite portcullises, which closed the passages before the apartment; and the entrance was not placed in the centre of the elevated masonry, where it could have been easily seen, but in the plain below.
The first group of pyramids is that of Memphis, the three principal of which are cchelloned on an elevated plateau, 120 stadia from Memphis and 45 from the Nile. The Largest of these—said by Iferodotus to have been built by Cheops, by Diodorus attributed to Chembes or Chabryes, and by Manetho and Eratosthenes to Stiphis or Saophis I.— f orm erl had a arse 764 ft. square, which luta been diminished, by the continual spoliation of the sides for material to build the city of Cairo, to 746 ft. Its ancient height, judging by the casing stones discovered by Colonel Howard Vyse, was 480 feet ; its present is only 450. The angle of its inclination is 51' 50'. It is built upon the rock, which has been cut down at the sides to obtain a level platform ; and its entrance, which lies 24 ft. 6 in. east of the centre of the north side, is 3 ft. 54 in. broad by 3 ft. II in. high, with an incline of 28° 41. This passage descends to the original sepulchral chamber of the pyramid, commonly called the subterraneous apartment, with a distance of 320 ft. 10 in. This apartment, which measures 46 ft. long by 27 ft. I in. wide, with a height of 11 ft. 6 in., has at its south end a horizontal passage of 52 ft. 9 in. long by 2 ft. 7 in. broad, and 2 ft. 8 in. high, leading south, apparently a continuation of the works in this direction for the purpose of forming a second sepulchral chamber for holding the furniture of the mummy ; but the work was abandoned in this direction, because the prolonged life of the monarch caused the mouth of the passage in the rock to be covered by the masonry added to the body of the pyramid. At the distance of 63 ft. 2 in. from the entrance another passage of the same size was constructed at an angle of 26° 18', and ran for 124 ft. 4 in. so slippery that the ascent was effected by small holes cut for the purpose, and then became a horizontal passage parallel to the plane of site of the pyramid, 109 ft. 11 in. long. Part of this passage is rather broader than the rest, and leads to a chamber commonly called the Queen's, having a groined roof, measuring 17 ft. by 18 ft. 9 in., and 20 ft. 3 in. high, having a recess at the east and placed nearly in the centre of the pyramid, at a distance of 67 ft. 4 in. from the fleer or plane of site of the pyramid. This chamber was evidently made for the reception of the sarcophagus, but was subsequently abandoned, and the ascending passage continued on a larger scale with granite bloOks 28 ft.