mardi 14 décembre 2010

Analyse de la Grande Pyramide par le minéralogiste anglais Edward Daniel Clarke (XVIIIe-XIXe s.)

C’est en observateur attentif, et plus spécialement comme minéralogiste, que le voyageur archéologue britannique Edward Daniel Clarke (1769-1822) a visité les pyramides de Guizeh.
De ses notes consignées dans l’ouvrage Travels in various countries of Europe, Asia and Africa (le texte ci-dessous est extrait de la 2e partie, 1817), on remarquera donc les précisions techniques concernant la nature des matériaux mis en œuvre dans la construction des pyramides (pierres, ciment). Les spécialistes apprécieront...
Le savant ne se limite toutefois pas à ce seul point de vue. Sa visite de la Grande Pyramide lui inspire d’autres observations dont je propose ici celles qui m’ont semblé les plus importantes et que j’ai très sommairement résumées dans les intertitres en français.

E.D. Clarke
“In the observations of travellers who had recently preceded us, we had heard the Pyramids described as huge objects which gave no satisfaction to the spectator, on account of their barbarous shape, and formal appearance : yet to us it appeared hardly possible, that persons susceptible of any feeling of sublimity could behold them unmoved. (...)
Having thus surveyed the principal objects, as they appeared from the summit of the greater pyramid, we proceeded to the examination of the substances which composed its exterior surface.

Nature des pierres
The stones of the platform upon the top, as well as most of the others used in constructing the decreasing ranges from the base upwards, are of soft limestone (...). It is of a greyish white colour; and has this remarkable property, that, when broken by a smart blow with a hammer, it exhales the fetid odour common to the dark limestone of the Dead Sea, and of many other places ; owing to the disengagement of a gaseous sulphureted hydrogen. This character is very uncommon in white limestone, although it may be frequently observed in the darker varieties. It is now very generally admitted that the stones, of which the Pyramids consist, are of the same nature as the calcareous rock whereon they stand, and that this was cut away in order to form them. Herodotus says they were brought from the Arabian side of the Nile. Another more compact variety of limestone is found in detached masses at the base of these structures, exactly as it is described by Strabo ; seeming to consist entirely of mineralized exuviae, derived from some animal now unknown. We did not observe this variety among the constituents of the Pyramids themselves, but in loose fragments upon the sand. The forms of the petrifaction are lenticular. (...)
Notwithstanding the throng of travellers, particularly of late years, who have resorted to the Pyramids, almost all of whom have borne away some memorial of their visit to the place, not a single specimen of this very curious variety of limestone has yet been observed in any collection of minerals, public or private.
Shaw mentions the mortar used in the construction of the Pyramids ; although a very erroneous notion be still prevalent, that the most antient buildings were erected without the use of cement. A reference to this kind of test has been frequently made, with a view to ascertain the age of antient architecture. All that can be asserted, however, upon this subject, with any degree of certainty, is, that if the most antient architecture of Greece sometimes exhibit examples of masonry without mortar, that of Egypt is very differently characterized. As we descended from the summit, we found mortar in all the seams of the different layers upon the outside of the pyramid ; but no such appearance could be discerned in the more perfect masonry of the interior. Of this mortar we detached and brought away several specimens, fragments of terra cotta. Grobert says it does not differ from the mortar now in use. Shaw believed it to consist of sand, wood ashes, and lime. (...)

Mesure de la hauteur de la Grande Pyramide
We were employed for a considerable time in a very useless manner, by endeavouring to measure the height of the greater pyramid. This we endeavoured to effect, by extending a small cord from the summit to the base, along the angles formed by the inclination of its planes ; and then measuring the base as accurately as possible, together with the angle of inclination subtended by the sides of the pyramid. The result, however, as it disagreed with any account hitherto published, did not satisfy us. It is a curious circumstance, that all accounts of its perpendicular height differ from each other. Some French engineers measured successively all the different ranges of stone, from the base to the summit. According to their observations, the height of this pyramid equals four hundred and forty-eight French feet. (...)

Photo Marc Chartier

L’entrée vers l’intérieur de la Grande Pyramide connue depuis les temps les plus anciens. Et peut-être cette pyramide n’a-t-elle été jamais complètement fermée...
Having collected our party upon a platform before the entrance of the passage leading to the interior, and lighted a number of tapers, we all descended into its dark mouth. In viewing this entrance, the impression made upon every one of us was, that no persons could thus have laid open the part of the pyramid where this channel was concealed, unless they had been previously acquainted with its situation ; and for obvious reasons. First, because its position is almost in the centre of one of its planes, instead of being at the base. Secondly, that no trace appears of those dilapidations which must have been the result of any search for a passage to the interior ; such, for example, as now remain for a memorial of the labours of the French near the smaller pyramid, which they attempted to open. The opening has been effected in the only point, over all the vast surface of the great pyramid, where, from the appearance of the stones inclined to each other above the mouth of the passage, any admission to the interior was originally intended. So marvellously concealed as this entrance must have been, shall we credit the legendary story of an Arabian writer, who, discoursing of the Wonders of Egypt, attributed the opening of this pyramid to Almamon, a Caliph of Babylon, about nine hundred and fifty years since ? A single observation of Strabo overturns its credit in an instant; as the same passage was evidently known to him, above eight centuries before the existence of the said Caliph. He describes not only the exact position of the mouth of the pyramid, but even the nature of the duct leading to the (...) Soros, in such a manner, that it is impossible to obtain, in fewer words, a more accurate description. It seems also true that this opening had been made before the time of Herodotus, although his testimony be less decisive. He speaks only of subterraneous chambers, but it were impossible to know any thing of their existence, unless the pyramid had first been entered. Hence it is evident, that a passage to the interior had been obtained from the earliest age in which any account was given of this pyramid ; and perhaps it never was so completely closed, but that with a little difficulty an access might be effected. (...)

Deux ou trois conduits, partant du passage horizontal , dont l’un débouche sur une petite pièce carrée
Some of the officers belonging to our party, while we were occupied in examining the well, had discovered two or three low ducts, or channels, bearing off from this passage [a horizontal duct, leading to a chamber with an angular roof, in the interior of the pyramid] to the east and west (like those intersecting veins called by miners cross-courses) and which they believed to have been overlooked by former travellers. Certainly there is no accurate notice of them in the descriptions given by Sandys, Greaves, Vansleb, Pococke, Shaw, Niebuhr, Maillet, Lucas, Norden, Savary, or any other author that we have consulted. Perhaps the French engineers employed under Menou in the examination of the Pyramids, by removing the stones which had closed the mouths of these channels, have laid them open. We undertook a most laborious and difficult task, in penetrating to the extremities of these ducts. The entrance being too low to admit a person upon his hands and knees, it was necessary to force a passage by lying flat upon our faces, gradually insinuating our bodies, by efforts with our arms and feet against the sides. The difficulty, too, was increased by the necessity of bearing lighted tapers in our hands, which were liable to be extinguished at every instant, in the efforts made to advance. As we continued to struggle in this manner, one after another, fearful of being at last jammed between the stones, or suffocated by heat and want of air, a number of bats, alarmed by our intrusion, endeavoured to make their escape. This we would gladly have permitted, but it was not easily effected. Flying against our hands and faces, they presently extinguished some of our tapers, and were with difficulty suffered to pass by us. After all our trouble, we observed little worth notice at the end of any of these cavities. In one, which the author examined, he found, at the extremity of the channel, a small square apartment, barely large enough to allow of his sitting upright ; the floor of which was covered with loose stones, promiscuously heaped, as by persons who had succeeded in clearing the passage leading thither. All these trifling channels and chambers are perhaps nothing more than so many vacant spaces, necessary in carrying on the work during the construction of this vast pile, which the workmen neglected to fill as the building proceeded (...).

Dans la “glorieuse chambre” : nature des blocs et état du “soros” (sarcophage), endommagé non par les Français, mais - hélas ! - par les militaires britanniques
Then quitting the passage altogether, we climbed the slippery and difficult ascent which leads to what is called the principal chamber. The workmanship, from its perfection, and its immense proportions, is truly astonishing. All around the spectator, as he proceeds, is full of majesty, of mystery, and of wonder. The materials of this gallery are said by Greaves to consist of white and polished marble. This we did not observe. Pococke also mentions pilastres in an anticloset before the principal chamber ; circumstances which are inconsistent with received opinions respecting antient architecture. The pilaster is believed to be of modern date; and marble, according to some writers, was not used by architects before the fifteenth Olympiad.
Presently we entered that "glorious room", as it is justly called by Greaves, where, "as within some consecrated oratory, Art may seem to have contended with Nature". It stands "in the very heart and centre of the pyramid, equidistant from all its sides, and almost in the midst between the basis and the top. The floor, the sides, the roof of it, are all made of vast and exquisite tables of Thebaick marble". By Greavess Thebaick marble is to be understood that most beautiful variety of granite called, by Italian lapidaries, Granito rosso, which is composed essentially of feldspar, of quartz, of mica. It is often called Oriental granite, and sometimes Egyptian granite, but it differs in no respect from European granite, except that the red feldspar enters more largely as a constituent into the mass than is usual in the granite of Europe. So exquisitely are the masses of this granite fitted to each other upon the sides of this chamber, that, being without cement, it is really impossible to force the blade of a knife between the joints. This has been often related before; but we actually tried the experiment, and found it to be true. (...)
Near the western side, stands the Soros, of the same kind of granite as that which is used for the walls of the chamber, and as exquisitely polished. It is distinguished by no difference, of form or dimensions from the common appearance of the Soros, as it is often seen in Turkish towns, when employed by the inhabitants to supply the place of a cistern. It resembles, as Greaves has remarked, " two cubes, finely set together, and hollowed within ; being cut smooth and plain", without sculpture or engraving of any kind. Its length on the outside is seven feet three inches and a half ; its depth, three feet three inches and three quarters ; and it is the same in breadth. Its position is north and south.
This beautiful relic was entire when our troops were landed in Egypt. Even the French had refused to violate a monument considered by travellers of every age and nation as consecrated by its antiquity ; having withstood the ravages of time above three thousand years, and all the chances of sacrilege to which it was exposed during that period from wanton indiscriminating barbarity. It is therefore painful to relate, that it is now no longer entire. The soldiers and sailors of our army and navy having had frequent access to the interior of the pyramid, carried with them sledge-hammers, to break off pieces, as curiosities to be conveyed to England ; and began, alas! the havoc of its demolition.”

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