Construction des pyramides : le point sur les connaissances au milieu du XIXe siècle, tel que proposé par une encyclopédie anglaise

Que peut-on attendre d'une encyclopédie, sinon une mise en forme, une présentation et une généralisation des connaissances, quel qu'en soit le domaine, à un moment donné de l'histoire ?

Tel est le cas de la Penny Cyclopædia de la Society for the Diffusion of Useful Knowledge, une encyclopédie anglaise éditée par George Long de 1833 à 1843, destinée à un lectorat "populaire" et issu des classes moyennes.

Le volume XIX (1841) comporte un développement sur les pyramides d'Égypte : on en trouvera de larges extraits ci-dessous.
Au milieu du XIXe siècle, lorsque paraît cette publication, les nouvelles découvertes au cœur des pyramides battent encore leur plein, dans la lignée des auteurs de la Description de l'Égypte, ainsi que des Davison, Vyse, Caviglia, Belzoni... On en est toujours au stade de l'inventaire, après des siècles et des siècles d'oubli ou de méconnaissance. On note toutefois que les "théories", qui feront florès par la suite avec le bouillonnement des hypothèses que l'on sait, n'occupent pas le devant de la scène : le "comment" des techniques utilisées pour édifier ces montagnes de pierre titille moins les esprits que de savoir ce qu'elles renferment derrière leurs façades encore partiellement muettes.
Il est vrai que le "comment" a déjà reçu une réponse, au demeurant la seule possible, qui semble devoir continuer à traverser allègrement les siècles : la parole est à Hérodote ! Oui, ce brave Monsieur Hérodote, qui a eu l'insigne privilège d'être instruit par des prêtres dépositaires du savoir égyptien. On sait ce qu'il adviendra par la suite de la crédibilité des assertions du "Père de l'Histoire". Mais pour l'heure, ne disposant pas d'éléments nouveaux pour alimenter le moteur de la réflexion, on se contente de reprendre, souvent mot à mot, des explications qu'il serait arrogant de prétendre contester.
Et pourtant... dans les lignes qui suivent, on commence à voir poindre quelques soupçons de légitime interrogation. Certes, l'historien de référence est toujours auréolé de ses connaissances transmises par qui de droit, mais quelques "pourquoi" font néanmoins leur apparition. Hérodote a bien écrit notamment que la pyramide de Khéops a reçu un revêtement de "remaining stones", lesquels blocs ont été mis en place "de haut en bas" ; mais où sont donc passés ces blocs ? "La difficulté est qu'aucune pierre, dont on pourrait prouver qu'elle ait appartenu (à la Grande Pyramide), n'existe sur cette pyramide ou à proximité. Il est probable que les pierres de revêtement, dont Hérodote dit qu'elles étaient très bien polies, ont été transportées ailleurs, pour servir à la construction. Il est pourtant extraordinaire qu'aucune ne demeure comme un témoin solitaire de la véracité du "Père de l'Histoire".

(Je rappelle que la barre d'outils ci-dessous comporte un onglet "traduction". Les traductions proposées sont loin d'être parfaites, mais... c'est mieux que rien !)

The pyramids of Egypt, especially the two largest of the pyramids of Jizeh, are the most stupendous masses of building in stone that human labour has ever been known to accomplish ; and we have records of their having been objects of wonder and curiosity from the age of Herodotus, who was born 484 years B.C., to the present time.

The Egyptian pyramids, of which, large and small, and in different states of preservation, the number is very considerable, are all situated on the west side of the Nile, and they extend, in an irregular line and in groups at some distance from each other, from the neighbourhood of Jizeh, in 30° N. lat. as far south as 29° N. lat., a length of between 60 and 70 miles.

The pyramids of Jizeh are nearly opposite to Cairo. They stand on a plateau or terrace of limestone, which is a projection from the Libyan mountain-chain. The surface of the terrace is barren and irregular, and is covered with sand and small fragments of rock : its height, measured from the base of the great pyramid, is 164 feet above the Nile in its low state, taken at an average ot the years 1798 to 1801. The north-east angle of tne great pyramid is 1700 yards from the canal which runs between the terrace and the Nile, and about five miles from the Nile itself. The accompanying plan, which is copied from the great French work Description de l'Égypte, shows the relative situations and sizes of these pyramids, and also the catacombs cut in the rock, the ruined buildings, and the great sphinx.

Herodotus was informed by the priests of Memphis that the great pyramid was built by Cheops, king of Egypt, about 900 B.C., or about 450 years before Herodotus visited Egypt. He says that 100,000 men were employed twenty years in building it, and that the body of Cheops was placed in a room beneath the bottom of the pyramid, surrounded by a vault to which the waters of the Nile were conveyed through a subterraneous tunnel ; a chamber under the centre of the pyramid has indeed been discovered, it is about 56 feet above the low-water level of the Nile. The second pyramid was built, Herodotus says, by Cephren, or Cephrenes, the brother and successor of Cheops ; and the third by Mycerinus, the son of Cheops.

It will be seen, from the preceding plan, that there are three large pyramids and several smaller ones. All of them have square bases, and their sides face the cardinal points.

The pyramid of Cheops consists of a series of platforms, each of which is smaller than the one on which it rests, and consequently presents the appearance of steps, which diminish in length from the bottom to the top. Of these steps there are 203, and the height of them decreases, but not regularly, from the bottom to the top, the greatest height being nearly four feet and two-thirds, and the least rather more than one foot and two-thirds. The horizontal lines of the platforms are perfectly straight, and the stones are cut and fitted to each other with the greatest nicety, and joined by a cement of lime with little or no sand in it. It has been ascertained that a bed eight inches deep has been cut in the rock to receive the lowest external course of stones. The vertical height, measured from this base in the rock to the top of the highest platform now remaining, is 456 feet. This platform has an area of about 1067 square feet, each side being 32 feet 8 inches. If to this were added what is necessary to complete the apex of the pyramid, the total height would be about 479 feet. Each side of the base, measured round the stones let into the rock, is rather more than 763 feet, and the perimeter of the base is therefore 3053'6 feet.

M. Jomard's figures differ a little from the above, in consequence of his measuring, not the lowest course of stones let into the rock, but the base of the steps which rest upon them. The whole height, according to him, would be nearly 473 feet, and he gives the following dimensions :

From this it appears that the faces of the pyramid are not equilateral triangles, as has sometimes been supposed.

(...) Mr. Davison, in 1763, discovered a chamber immediately over the king's chamber, which is reached by mounting by a ladder to a hole at the top of the upper ascending gallery ; and Colonel Vyse has since (1836-7) discovered three other chambers, also above the king's chamber. All these chambers are from three to four feet longer than the king's chamber, and about the same width, the slabs which are the roof of the one forming the pavement of that which is above it ; but none of them is much more than three feet high. They have probably been formed merely to lessen the weight of the mass above the king's chamber.

Captain Caviglia, in 1816, discovered that the entrance passage did not terminate at the bottom of the ascending passage, but was continued downwards in the same inclined plane 200 feet farther, and by a short horizontal passage opened on what appeared to be the bottom of the well. The passage however continued in the same direction 23 feet farther, then became narrower, and was continued horizontally 28 feet more, when it opened into a large chamber cut in the rock, and under the centre of the pyramid. This chamber is about 26 feet by 27. Another passage 55 feet long leads from this chamber, but it appears to terminate abruptly.

The well, which appeared to Mr. Davison and Captain Caviglia to descend no lower than where it was intersected by the descending passage, its depth there being 155 feet, was afterwards cleared out by the French to the depth of 207-75 feet, of which about 145 feet are in the solid rock ; to that the base of the pyramid being 164 feet above the low-water level of the Nile, the present bottom of the well is 13 feet 6 inches abore the Nile ; but the actual bottom does not appear to have been yet reached. The temperature within the body of the pyramid was found to be 81° 5' Fahrenheit, and in the well it was still higher.

Herodotus was informed that the chambers cut in the solid rock were made before the building of the pyramid was commenced. It is evident that it was intended that the pyramid should not be entered after the body or bodies were deposited in it, as blocks of granite were fixed in the entrances to the principal passages in such a manner as not only to close them up, but to conceal them. There are traces however of the pyramid having been entered both by the Romans and the Arab conquerors of Egypt.

As the pyramids consist of a series of platforms, each smaller than the one on which it rests, the height of none of them being so much as five feet, and that height diminishing upwards, it is obvious that the stones could be lifted by manual labour and levers successively from step to step, so as to complete each platform before the next was comrnenced ; but there is a passage in Herodotus respecting the building of this pyramid which is attended with a little difficulty. He says : "The pyramid was made in the following manner, in the form of steps, which some call crossae (battlements), and others bomides (little altars). When they had first built it in this fashion, they raised the remaining stones by machines or contrivances of short pieces of wood. They raised them from the ground to the first tier of steps, and when the stone had ascended to this tier, it was placed on another machine standing on the first row, and from this row it was dragged upon the second row on another machine. As many tiers of stones as there were, so many machines also were there ; but, according to another account (for I think it right to give both accounts as they were given to me), they transferred the same machine, it being easily moved from step to step as they raised each stone. The highest parts were accordingly finished first ; then the parts next to the highest, and last of all the parts near the ground and the very bottom."

The "remaining stones" have sometimes been interpreted to mean casing-stones, similar to those which yet remain on the upper part of the pyramid of Cephren, and by which the whole surface was made smooth. And this indeed would be the only judicious way of putting on such a casing : otherwise, if they began from the bottom, the lower part of the pyramid would be rendered inaccessible, and the stones could only be carried up by external contrivances. There is no doubt that it had such a casing, but the difficulty is, that not a stone that can be proved to have belonged to it now exists either on or about the great pyramid. It is probable that the outer stones, which Herodotus says were highly polished, have been carried off for purposes of building, but it is extraordinary that not one should remain as a solitary witness for the veracity of the Father of History.

Herodotus also informs us that when the great pyramid was designed, they began by making a causeway for the conveyance of the stone. This causeway was 3000 Greek feet in length, 60 in breadth, and 48 high at its greatest elevation. It was made of highly polished stone covered with sculptures ; and in his opinion was as wonderful a work as the pyramid itself. Of this causeway however there are now no traces, though remains of causeways, along which the materials of the pyramids were probably conveyed, may be seen in many places (...).

The materials of all the pyramids are limestone, and Belzoni is of opinion that part of the stone for the second pyramid was procured immediately on the spot, judging from the manner in wnich the rock has been cut away round the pyramid. Herodotus certainly understood that all the stone was brought from the mountains near Cairo, where there are indeed antient quarries of great extent ; but it seems probable that the greatest part of the materials came from the west side of the Nile. The blocks of granite were of course brought from Syene, which is nearly 500 miles higher up the Nile. The rock on which the great pyramid stands has been found to project at least as high as 80 feet into the body of it. The stones of which it is built rarely exceed nine feet in length and six and a half in breadth ; the thickness has been already stated.

The ascent of the great pyramid, though not without difficulty and danger, from the broken state of the steps, is frequently accomplished, and even by females. Belzoni describes the view from the top in terms of enthusiastic admiration.

(...) [The] second pyramid does not rise from the natural level of the plateau, but out of an excavation or deep cut made in the solid rock all round the pyramid. The rock in which this excavation has been made is higher than that on which the great pyramid stands, so that both pyramids may stand on the same level, but this does not seem to have been accurately ascertained.
Belzoni, after great exertion, succeeded in opening the second pyramid, and after traversing passages similar to those in the great pyramid, reached the main chamber, which is cut out of the solid rock. It is 46 feet 3 inches long, 16 feet 3 inches wide, and 23 feet 6 inches high. The covering is made of blocks of limestone, which meet in an angular point, and form a roof of the same slope as the pyramid. The chamber contained a sarcophagus, formed of the finest granite, which is 8 feet long, 3 feet 6 inches wide, and 2 feet 3 inches deep in the inside. There were no hieroglyphics on it. Some bones were found in it, which were ascertained to be those of an ox. From an Arabic inscription on the wall of the chamber, it appears that some of the Arab rulers of Egypt had entered this pyramid and closed it again. Belzoni also discovered another chamber in this pyramid.