mercredi 13 janvier 2010

Techniques de construction des pyramides de Guizeh : l'analyse du British Museum au XIXe s.

On le sait : les musées ont vocation éducative. D'où les publications que lesdites institutions, de par le monde, s'ingénient à intégrer dans leur mode de fonctionnement.
Tel est le cas du British Museum, détenteur, comme chacun sait, de précieuses Egyptian antiquities, dont une certaine pierre de Rosette.
À preuve, le texte ci-dessous qui est extrait de "The British Museum - Egyptian antiquities", vol. 2, ouvrage collectif, sous la direction de Lord Brougham, 1836.
Je l'ai retenu pour ses développements concernant les pyramides de Guizeh.

À toutes fins utiles, voici quelques grandes lignes des extraits choisis :
- le nombre des pyramides laisse subsister quelque doute : en tout cas, il fut plus élevé que celui que nous connaissons actuellement ;
- selon Hérodote, dont les écrits ne sont pas exempts de toute obscurité, la Grande Pyramide fut entièrement revêtue d'une couche de blocs de finition, pour devenir entièrement lisse et empêcher quiconque de monter au sommet ; mais, compte tenu des observations des voyageurs, cette question reste "difficile à résoudre" ;
- il est difficile d'évaluer l'étendue des dommages causés aux pyramides, pour construire le Caire, par les "Arab conquerors of Egypt" ;
- conformément à ce qu'affirmait Jean-Marie-Joseph Coutelle, en prenant ses distances par rapport à ce qu'écrivait Hérodote, la hauteur des degrés de la Grande Pyramide ne décroît pas régulièrement ;
- le noyau de la grande et de la seconde pyramide n'a pas été construit avec le même soin que l'extérieur de ces monuments ;
- les pyramides, contrairement à ce que pensait Belzoni, ont dû être couvertes de textes hiéroglyphiques ;
- la chambre souterraine de la Grande Pyramide n'a jamais été le lieu de sépulture du pharaon, ni un puits ; puis cette étrange affirmation :"Si nous considérons l'énorme masse de la [Grande] Pyramide, il peut très bien y avoir plus d'un millier de chambres qui n'ont pas encore été ouvertes, et encore plus de chambres qui ont été taillées dans le rocher sur lequel la pyramide repose."
- concernant à nouveau le revêtement des deux grandes pyramides de Guizeh, les auteurs du texte affirment avec certitude que, même si le doute subsiste sur la nature des matériaux utilisés, la couche de blocs extérieurs a fait l'objet d'une bien meilleure finition ; ils se demandent toutefois, sans préciser leur opinion, si les blocs de cette couche extérieure ont été transportés et taillés une fois mis en place, ou bien si ces blocs, comme cela semble l'avis d'Hérodote, ont été transportés après avoir été préalablement taillés.

The number of pyramids, large and small, now existing (...) in various states of preservation, is not accurately ascertained ; but whatever it may be, we know that there was once a greater number than there is now. Many of the smaller pyramids have been used as materials for modern constructions, and even the larger masses have not been entirely safe from the hands of destroyers. Some have partly crumbled away, owing to the nature of their materials, as that of Illaoun or El-Lâhoun, near the entrance of the Faioum territority, which is built of sun-dried bricks.

(...) The base of the great pyramid is a square, each side of which is 232'747 metres, or 763'4 ft. This measurement was obtained along the base of the north side, between the extreme N.E. and the extreme N.W. angle, by digging down to the true base of the pyramid. A hole was found at the N.E. angle, 12'79 ft. long, 11'15 ft. wide, and about eight inches deep, which had contained the extreme N.E. stone of the pyramid. The vertical height from the base of the stone let into the foundation to the two broken steps on the top of the platform is a little more than 456 feet, as determined by measuring the separate steps, which are 203 in number ; and if to this we add what is necessary to complete the apex of the pyramid, the total height will be about 479 feet.

(...) This description [celle d'Hérodote] is not quite free from obscurity. The "remaining stones" have sometimes been interpreted to be a kind of casing, formed of triangular prismatic blocks, which made the whole surface smooth. All that we can safely infer from the passage of Herodotus is, that according to his notion, an outer series of stones was added by way of finish ; and as they began this finish from the top, it is pretty certain that, according to his ideas, it could not have been an additional tier of stones, in the form of steps, but something that rendered it either impossible or very difficult to begin from the bottom. The general inference, then, is that something like a smooth face was given to the pyramid, both for the purpose of improving its appearance, and also, perhaps, rendering it inaccessible ; for we may perhaps infer from the silence of Herodotus that it was not the practice to ascend the pyramids in his time. Pliny (whether referring to his own age, or taking the fact from other authors - a distinction that Pliny seldom gives us the means for making) says that the people of Busiris, which is near the pyramids, were accustomed to climb them. (...)

The statement of Herodotus as to the magnitude of the stones is much exaggerated. M. Coutelle remarks (and we place great confidence in what he says), that the stones of the great pyramid, and those of the second, belonging to the outer covering, that are not taken away, rarely exceed nine feet in length and six and a half in breadth. The thickness or height of the steps in the great pyramid has been already stated. M. Coutelle remarks, that the height of the steps does not decrease regularly, as we ascend the pyramid, but that steps of greater height are sometimes interposed between steps of less height ; but he adds, the same level and the same perfectly horizontal lines appear on all the faces. In the second pyramid the outer stones of the upper part, which still remain, are cut with the greatest nicety and made quite smooth, except on the side that is engaged in the interior masonry. The kernel or interior part of the pyramid is not built with the same care : the stones of each tier are not always of the same height, nor accurately joined : the vacant spaces are filled with coarse mortar, pieces of broken stone, and pebbles, a form of building which was quite sufficient for the interior parts. M. Coutelle remarks that no lines could be straighter, and no joinings more exact, than are observed in the interior of the great pyramid, and on the upper part of the exterior of the second. Herodotus describes the first pyramid as built of "polished stones, fitted together with the greatest nicety." Now, as this is not the case at present with the exterior of the great pyramid, which is so irregular as to have led Mrs. Lushington to say there are no steps, and Niebuhr to make the remark just quoted, it is clear that if the account of Herodotus is not a deliberate falsehood, an outer tier or casing of stones (by what name it is called is indifferent) has been taken from the great pyramid.

All travellers agree that there are not the slightest traces of this pyramid having ever had a casing, for so they assume that Herodotus describes it ; while the second pyramid (attributed to Chephren), they say, has some of this coating on the upper part and none on the lower parts. This would seem to confirm Herodotus's account of the upper part of what is called his casing being finished first, but it might prove at the same time that the outward casing of the second pyramid was never completed (...).

With respect to this question of the coating of the great pyramid it is difficult to decide, as the evidence of Herodotus and the Arab writers is at variance with the opinion of nearly all modern travellers.

We know that the pyramids were used as building materials by the Arab conquerors of Egypt, and it is difficult to calculate how much damage may have been done in the course of several successive centuries of robbery. Karakousch, one of the emirs of Salah-eddin Yousouf, absolutely destroyed a number of small pyramids, and with these and other materials built the arches near Jizeh, which we have already mentioned, and decorated the capital, Cairo.

(...) It may (...) have been the design of the pyramids also, as Belzoni argues, to be without hieroglyphics. We doubt the soundness of this hypothesis, and would rather attempt to show that the pyramids once had hieroglyphics on them, from the following evidence : Abdallattif speaks of these pyramids being covered with an unknown character which nobody in Egypt could understand ; and he adds, in the style of oriental hyperbole, "these inscriptions are so numerous that if one were to copy only those on the surface of the two (larger) pyramids, it would fill more than ten thousand pages".

In addition to this evidence, the reader may examine what De Sacy has collected in his notes from other Arab writers, and Jomard in his remarks on the pyramids, as to the inscriptions on the pyramids, and he will find it rather difficult to believe that they are all telling a falsehood. Finally, we have the testimony of Herodotus, as to a particular inscription on the great pyramid, which by no means excludes the probability of other inscriptions ; and we have his evidence most distinctly, to show that the grand ascent or staircase, from the plain to the level of the pyramids, was made of stone and covered with intaglios, like the propyla of Luxor and Edfou.

(...) [À propos de la chambre souterraine] This (...) is neither the tomb of Cheops nor the well of Pliny, being about thirty feet above the highest level of the Nile, and having no inlet. It is true there is a long passage which leads from this chamber to the length of fifty-five feet, but it terminates abruptly. But it has been well remarked, if we consider the enormous mass of the pyramid, that there may be more than a thousand chambers still unopened, and many more chambers also cut out of the solid rock on which it rests. This pyramid, doubtless, has been entered, as we infer from various traces, both by the Romans and the Arab conquerors of Egypt. Captain Caviglia ascertained one curious fact. The rock which shows itself externally at the north-eastern angle is seen again in the main passage, and near the mouth of the well. The highest projection of it into the body of the pyramid is about eighty feet above the base.

(...) In speaking of the great pyramid, we have translated the words of Herodotus literally, without however adopting the common notion, that after the pyramid was built in the form of receding stages or steps, it was completed by filling up the receding spaces with prismatic blocks, beginning at the top. Herodotus may or may not have correctly described the mode of building the pyramids ; but we must take the plain meaning of the text as the expression of what he meant to say. The second pyramid, as already observed, is said to retain a large part of what has been usually called its casing ; but Belzoni is of opinion that the casing was never completed. M. Jomard describes this covering as a compact limestone. At a distance, large spots appear on it, some of which are produced by the dung of birds, and others of a reddish appearance, by a species of lichen, hitherto undescribed. But he is inclined to think, that the lower part was covered with granite (Herodotus says the same), from having seen several prismatic blocks of granite lying at the bottom of the steps, and one lying in the direction north and south, and about nine feet from the south-west angle of the pyramid. M. Coutelle, on the contrary, decides, we think correctly, that these prismatic blocks, as Jomard calls them, could not have been used in the construction of the pyramid.

(...) We believe that we can now explain this matter of the casing in a tolerably satisfactory manner. It appears that all the outer tiers of stones in the two pyramids, whether of finer quality than the rest or not, were arranged with some more care, and better worked, than the stones of the interior. There is no doubt, also, that the salient edges formed by each tier were cut off, so as to give the sides a tolerably smooth surface ; for it seems, as Niebuhr observes, not to have been the intention of the architect that these buildings, when finished, should be ascended, nor indeed entered at all, as the openings were carefully blocked up. The immense mass which M. Jomard saw over his head, was the under side of the stone which was in a position immediately above that which once occupied the vacant space where he stood. Now this being apparently the explanation of the casing, as it is called, the only question is, whether the last outside stones were carried to their respective places and then cut so as to form a plain surface on the side of the pyramid, or whether, as Herodotus seems to have understood it, the stones were carried up ready cut : this latter method would evidently be a saving of trouble. Coutelle objects to the notion of triangular prisms being used to fill up the spaces, that this would be an insecure way of building ; and so it would : but it is not necessary to suppose that the outer stones were carried up entire, and then cut. The stones might have been cut in the following form, and in this state applied to the pyramid, beginning at the top and going down to the bottom.

Les illustrations sont extraites de l'article

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