mardi 13 juillet 2010

La construction des pyramides, selon Hérodote revu et non corrigé par des ingénieurs civils du XIXe siècle

On pouvait peut-être s'attendre à mieux de la part d'ingénieurs civils ! Disons : un peu plus de distance par rapport à la relation d'Hérodote et à ses "machines fabriquées avec de petits morceaux de bois". Mais il faut bien le reconnaître : de longs siècles durant, on n'avait guère d'autre référence prétendument sérieuse à se mettre sous la plume que le célèbre "Père de l'Histoire".
Il n'y a donc aucune révélation particulière à attendre du texte qui suit, extrait de la revue Civil Engineer and Architect's Journal, scientific and railway gazette, vol. IV, 1841. On relèvera pourtant une comparaison intéressante entre la "perfection intellectuelle" des Grecs et la qualité de ce que l'on appellerait aujourd'hui "l'aménagement du territoire", où les Égyptiens ont excellé grâce à la qualité de leurs travaux publics, qui leur ont permis de faire de leur pays le grenier de l'Europe.

Photo Marc Chartier
Engineering works of the Ancients, n° 2, February 16, 1811
"Continuing our notes from Herodotus, the present paper will principally relate to the Egyptians, whose works like those of the Babylonians, have an interest for us, as giving rise also to a school on which Greek engineering was founded. It is one of the most ancient of which we possess authentic monuments and records. The Egyptians like the Babylonians principally devoted themselves to hydraulic engineering, in which they made great progress ; their other works also afford convincing proofs of their attainments in other departments of the art. The account of Egypt in Herodotus might be almost termed a history of engineering in that country, where it was called into play as one of the great instruments of national advancement, the exploits of a prince consisting as much in the works he executed, as in the victories which he obtained. This is one of the features of a system of polity, to which Egypt was indebted for great social progress, and an exemption from many of the evils which afflicted surrounding nations. If from moral causes Egypt never attained the intellectual perfection of the Greeks, yet by the extent of its public works the country was brought into a high state of cultivation and productiveness, so as to make it for centuries the granary of Europe. It was less owing perhaps to the fertility of the soil, than to the facilities afforded as to internal communication, that the resources of Egypt were made so extensively available.

Causeway of Cheops
Cheops, it is said by our author, degenerated into extreme profligacy of conduct, and oppressing the Egyptians, in every way, he proceeded to make them labour servilely for himself. Some he compelled to hew stones in the quarries of the Arabian (query) mountains, and drag them to the banks of the Nile ; others were appointed to receive them in vessels and transport them to a mountain in Libya. For this service a hundred thousand men were employed, who were relieved every three months. Ten years were consumed in the hard labour of forming the road, through which these stones were to be drawn ; a work cited by Herodotus as equal in difficulty to the pyramid itself. This causeway was five stadia in length, forty cubits wide, and its extreme height thirty-two cubits, the whole of polished marble, adorned with the figures of animals. So far our author, a modern account by Pococke and Norden, says that there is still a causeway running part of the way from the canal which passes about two miles north of the pyramids. This extends about a thousand yards in length, and twenty feet wide, built of hewn freestone. It is strengthened on either side with semicircular buttresses, about fourteen feet diameter, and thirty feet apart. There are sixty-one of these buttresses, beginning from the north. Sixty feet farther it turns to the west for a little way, then there is a bridge of about twelve arches, twenty feet wide, built on piers that are ten feet wide. Above one hundred yards farther there is another bridge, beyond which the causeway continues, about one hundred yards to the south, ending about a mile from the pyramids where the ground is higher. The reason for building this causeway and keeping it in repair seems to be the lowness of the country, the water lying on it a great while.

The Great Pyramid - the Middle Pyramid - Third Pyramid
As we are rather giving common-place notes from the individual authors, than complete accounts of the works, we have less compunction in copying what Herodotus says of the much-written subject of the pyramids. Having described the causeway just mentioned, our author goes on to say that a considerable time was consumed in making the vaults of the hill on which the pyramids are erected. These he intended as a place of burial for himself, and were in an island which he formed by introducing the waters of the Nile. The pyramid itself was a work of twenty years : it is of a square form ; every front is eight plethra long, and as many in height ; the stones very skilfully cemented, and none of them of less dimensions than thirty feet. The ascent of the pyramid was regularly graduated by what some call steps and others altars. Having finished the first flight, they elevated the stones to the second by the aid of machines constructed of short pieces of wood (supposed by some to be the pulley) ; from the second, by a similar engine, they were raised to the third, and so on to the summit. Thus there were as many machines as there were regular divisions in the ascent of the pyramid, though in fact there might be only one, which being easily manageable, might be removed from one range of the building to another, as often as occasion made it necessary ; both modes have been told me, says Herodotus, and I know not which best deserves credit. The summit of the pyramid was first of all finished off ; descending hence, they regularly completed the whole. Upon the outride were inscribed in Egyptian characters, the various sums of money expended in the progress of the work for the radishes, onions and garlic consumed by the artificers.
The middle pyramid, attributed to the daughter of Cheops, is stated to have an elevation on each side of one hundred and fifty feet.
Chephren, the brother of Cheops, is mentioned as the builder of the third pyramid, which was less than his brother's. It has no subterraneous chambers, nor any channel for the admission of the Nile. The ascent is entirely of Ethiopian marble of divers colours, but it is not so high as the larger pyramid by forty feet. The pyramid stands on the same hill as that of Cheops, which hill is near one hundred feet high."

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