Gilles Dormion Jean-Yves Verd’hurt The pyramid of Meidum, architectural study of the inner arrangement. civilisation pharaonique: archéologie, philologie et histoire World Congress of Egyptology, Cairo, 28th of March-3nd of April 2000 Gilles Dormion et Jean-Yves Verd’hurt, The pyramid of Meidum, architectural study of the inner arrangement The pyramid of Meidum, attributed to the first King of the IVth Dynasty, Snefru, is mainly known for the successive transformations of its outer mass. Step monument in its original design, in the tradition of the monuments of Zoser, Sekhemkhet, and Zawiyet el-Aryan, the pyramid of Meidum was built with inward-sloping sides towards the nucleus. Then an enlargement was undertaken, converting the seven-stepped pyramid into a pyramid with eight steps that were filled in with horizontal-bed masonry, which transformed the monument into the first true pyramid. Finally, the collapse and/or the pillage of these coatings, which is its characteristic shape today. Such special evolution has often been studied and described, maybe to the detriment of its inner arrangement. Owing to the limited dimensions of the apartments and the elementary nature of their layout, the pyramid looks quite simple and does not seem to pose any particular problem. A corridor leads downwards, first through the core of the pyramid, then under the level of the rocky plateau, and goes on horizontally, built in a trench hewn in the plateau. At the end of the corridor a vertical shaft leads upwards and opens in a burial chamber which is built at the level of the rock levelling and covered with a corbelled roof (see plan I). Or a great anomaly in this architectural arrangement caught our attention, and this study was motivated by its logical analysis. The horizontal corridor that connects the descending corridor to the « shaft » leading to the upper chamber has two recesses, whose dimensions are 2.60 m NS (5 cubits) x 2.10 m EW (4 cubits) and whose height from the floor -1.75 m- is equal to that of the corridor (plate I). The ceiling shared by the corridor and the « recesses » is made of a succession of lintels forming a flat roof. At right angles with the « recesses » the span of the lintels is 2.10 m (4 cubits). Covering a 2.10 m span with a flat roof is quite unusual in the architecture of the Old Empire pyramids: the builders, aware of the weight to be implemented, usually used the technique of the corbelled roof in order to cover spans more than 1.05 m (2 cubits). Considering that the span covered is exceptional with a flat roof and that the lintels do not show any significant cracks, it is hardly likely that the builders of the pyramid of Meidum took the risk of putting the weight directly on these lintels, whose span was so great, and that induces us to think that there is a relieving system above the flat roof itself. Such a device, supposed to be made with a corbelled roof according to the technique used at that time, would indicate the presence of « relieving chambers » above the « recesses ». May 1998 As part of this hypothesis, we meticulously observed the masonry in order to detect a significant detail: from the first day, in the upper section of the shaft, we discovered a bonding symptomatic of a walled aperture we called « window » (plate II). The walled « window » is 99.5 cm high and 74 cm wide at the base; it narrows into a trapezium at the top. This section is too reduced, especially in height, to be the mouth of a real corridor; on the other hand, it could be the opening of a narrow passageway for technical use. The east rising joint, at right angles with the block B3, shows a gap 1 cm wide which has no mortar and would enable the passing of an endoscope without any damage. On the 25th of May 1998, upon examination, the Franco-Egyptian working team decided to introduce an endoscope through this joint (flexible endoscope Olympus, 1.50 m in length, 8 mm in diameter, with light source and adjustable head). In the presence of Mr Mustapha El Zeiry, Dr Samir Abdel Halim, Dr Shawki Nahkla, Mr Mohsen, Mr Korani, Mr Gilles Dormion and Mr Jean-Yves Verd’hurt, the operation was executed without difficulty and a small corridor behind the walled window was discovered. The endoscope enabled us to observe that this small corridor was corbelled. There were substantial salt formations on the masonry. The floor was strewn with debris from split stones, and salt crystals that had fallen from the side walls. The corridor was estimated to be 3 m long. A series of photos was taken with the endoscope. In order to complete the observations more precisely, Dr Mustapha El Zeiry authorized to remove the upper stone B4. This operation was made on the 26th of May in the morning. The 40 cm thick stone removed showed an opening 26 cm high and 33 cmwide. Direct observation was thus possible together with photographies from different angles. I. Description a. Walled part called « window » (plate II) The four blocks B1 B2 B3 B4 that wall up the opening are about 40 cm thick. On the east side the stones are laid against the inner corbels of the corridor and badly joined with gypsum (the rising joint of the stone B3 has practically no mortar). On the west side the wall is cut as a trapezium for a depth of 13 cm. Between the block B1 and the upper joint a stone, accurately cut, was inserted. The visible piece of wood above the window is fitted for a depth of about 40 cm into the gap of the upper corbel. b. The cavity (plate III-IV) It is a kind of small corridor going north-south, straight above the lower corridor. Its dimensions are 2.80 m long, 0.75 m wide at the base and 1.44 m high. The pavement of the corridor would thus be 3.40 m above the roof of the lower corridor. The corridor is made of three visible corbelled courses. The substantial salt formations and the splitting of the stones do not enable us to know the real quality of the masonry which, however, seems quite comparable to that of the burial chamber. The top level of the last corbel (that corresponds to the upper end of the piece of wood visible from the outside) seems to correspond exactly to the level of the natural rock. The north end of the corridor, which was difficult to observe in detail (considering the distance of observation -2.80 m- and the two slabs of split stones which partially hide the base) looked smooth and even, with no visible joints and no substantial salt formations, contrary to the rest of the masonry. The opening made was closed that same day with a limestone block cut to size and joined with plaster. II. Comments The position of this corbelled device straight above the lower corridor suggests that its purpose is to relieve it. It is worth pointing out as well that if the builders had found it necessary to relieve a corridor 0.75 m (10 palms) wide, such a precaution should have proved particularly essential with regard to both recesses whose span was three times as great (2.10 m = 4 cubits). That corresponds to the hypothesis which has motivated this study, that is to say it is to be architecturally expected that both recesses should be surmounted by a relieving roof. The removing of a stone in the upper part of the window had enabled us to see a small corridor but not to enter it. After having consulted the Egyptian Antiquities, a second stone was removed in order to make a sufficient gap. The thick layer (about 25 cm) of debris strewing the floor was cleared away. The debris were sorted in order to check if they did not have any element of archeological importance. They were mainly composed of split limestone pieces and of salt formations in large amounts that had come off the side walls and the corbels. Some samples were given to the Egyptian Antiquities for analysis. May 1999 As the north side wall of the small corridor discovered was supposed to be situated less than one metre from a relieving chamber expected to be straight above the southern recess, we decided to make a hole to check the existence of such a chamber. We made an opening 16 mm of diameter in the joint of the western lower corner of the north side wall of the corridor. Easily made for 95 cm in length, this opening led to an empty space. We introduced an endoscope which enabled us to see a small built chamber we meticulously and lengthily observed, then photographed. I. Description of the chamber (subject to the restraints and the limits of an observation with an endoscope) (plate V-VI) As we thought, it seems to be exactly situated straight above the southern recess with the same dimensions (east-west: 2.10 m, 4 cubits; north-south: 2.61 m, 5 cubits). It is covered with a corbelled roof. It is made of seven courses: two vertical ones at the base, then five corbelled ones. The floor does not have any pavement, and is not even: it is made of the upper side of the three beams covering the southern recess. These beams seem to have different heights (exactly as in the relieving chambers of the pyramid of Cheops). The north wall is made of seven courses, the three upper courses seem to have successive recesses. The south wall is made of five courses; only one stone corresponds to the three upper corbels and to the north side wall of the small corridor. The ceiling ridge of the chamber seems to correspond in height to that of the small corridor, that is to say the level of the natural rock levelling. The chamber does not seem to lead anywhere. The masonry is carefully made: the beds of the courses of the north and south walls correspond to those of the existing corbels (except for the lower corbel). The chamber looks well-preserved. The side walls are neither split nor damaged as in the other sections known of the pyramid, and do not seem to have any salt formations as in the small corridor recently discovered. The floor is strewn with few debris. Only a significant block has come off the second course of the west wall. II. Comments The fact that the chamber is exactly situated straight above the southern recess, directly laid on the beams covering the recess without evenness and pavement, and blind, leads us to think that the only function is to relieve the southern recess. What surprised us most is the excellent state of preservation of the chamber. It seems that the damage due to moisture and salt, visible in the other sections that can be visited and in the small corridor discovered, has not affected this chamber at all. This fact is reassuring but raises the question of the state of the sections known of the pyramid, and of the problems linked to its preservation, namely: Has the moisture saturation of the sections visited an inevitable endogenous origin (rising damp from the ground water through the sections that are not built — the shaft, the floor of the burial chamber)? Has it an exogenous origin (moisture brought by visitors and not eliminated)? Or both at the same time? Concerned about this angle of the problem, we took particular care not to cause atmospheric exchanges between the sections visited and the virgin chamber. For this purpose, we sheathed the 16 mm opening in order to leave no gap between it and the 8 mm endoscope, and it was filled up between each handling and hermetically plugged at the end of the works. September 1999 The existence of a relieving chamber above the southern recess implied the existence of a similar chamber expected to be situated above the northern recess. In order to see that chamber, we made a hole (18 mm in diameter, 1.30 m long) without any difficulty in the first section of the descending corridor. This opening led to the north-west corner of the chamber floor; we introduced a video-endoscope and we thus observed a chamber almost similar to the one previously discovered above the southern recess. I. Description of the chamber (subject to the restraints and limits of an observation with an endoscope) (plate VII) As was planned, it is situated straight above the northern recess, with the same dimensions (east-west: 2.10 m — 4 cubits; north-south: 2.65 m — 5 cubits; about 3.50 m in height). It is covered with a corbelled roof. The east and west walls are made of seven courses: two vertical ones at the base, then five corbelled ones. The south wall is vertical and is made of seven courses. Observed with difficulty, the north wall is vertical. The ceiling ridge of the chamber seems to correspond in height to that of the chamber above the southern recess, that is say the level of the natural rock levelling. The floor does not have any pavement: it is made of the upper side of the three beams which cover the northern recess. The masonry is well made, but is not re-dressed. Under the projecting faces of several corbels we can clearly see fine straight lines of red hematite drawn by the builders. In the western lower corner of the north wall we can see a hole situated straight above the descending corridor. The stones that form the opening of this hole form an angle which seems to correspond to the slope of the descending corridor; therefore it seems obvious that it is the mouth of a relieving corridor situated above the ceiling of the descending corridor. The chamber looks well-preserved. The side walls are neither split nor damaged as in the other sections known of the pyramid, and do not have significant salt formations as in the small corridor behind the window previously discovered. The floor is strewn with few debris. However some large blocks have come off the upper corbels; one of them, situated in front of the endoscope, obstructed the observation. II. Comments The comments and conclusions we can make are exactly the same and corroborate those we previously formulated. III. Observation of the relieving corridor In order to observe the corridor whose mouth we had noted in the north wall of the chamber, we made an opening (18 mm in diameter, 0.90 m long) in the ceiling of the descending corridor, 10 metres up from its lower end, and we introduced the video-endoscope. IV. Description of the corridor (plate VIII) Its construction is similar to that of the small corridor discovered behind the window. Its dimensions seem to be roughly 0.75 m wide, 1.40 m high. Its east and west walls are made of three corbelled courses above the beams that form the ceiling of the descending corridor. The masonry is roughly made. It is well-preserved. We do not observe any salt formations. The floor is strewn with a few debris that have come off the side walls. We cannot see the south and north ends: it would seem that it covers the descending corridor for its whole length. This point will have to be checked later. We know that it opens in the south to the northern chamber previously discovered, but it would be interesting to know if it ends in the north at right angles with the initial casing of the pyramid. On the 31st of March 2000, in order to know the length of the relieving corridor above the descending corridor, we made two drill holes. The first one, situated in the corridor ceiling 19.70 m from its lower end, 2 m in depth, did not meet any empty space. The second one, made in the ceiling 12.56 m from the lower end, led into the relieving empty space. The introduction of the endoscope enabled us to see the corridor and its upper end. To the best of our judgement with an observation, the relieving corridor ends about 2.50 m up from the drill hole, that is to say about 15 m from its lower end. The relieving corridor is just as we had previously observed it further down. Three corbels are directly laid on the top faces of the beams of the descending corridor. The top of the beams is not uneven; all the beams of the descending corridor have the same height and make a flat floor in the relieving corridor. About 2.50 m up from the drill hole, the relieving corridor ends against a monolithic stone laid perpendicular to the slope. The corbels rest against this stone. It is laid on the floor (top faces of the beams of the descending corridor) with a wide joint without mortar. In the stone axis we can clearly see a vertical rectilinear brown line. We first thought that it could be a hematite line for the setting up axis, but it might actually be a fine flow mark coming from the corbels axis. Finally we can notice that the 15 metre length of the relieving corridor seems to correspond to the spot where the descending corridor is not built in trench in the ground any longer. If this relieving corridor ended at the outer face of the inner core of the pyramid, against which the first coating layer is laid, this inner core would be 80 cubits wide at the base. As before for the southern chamber, we took particular care not to cause atmospheric exchanges between the sections visited and the virgin ones. For this purpose, we sheathed the 18 mm openings in order to leave no gap between them and the 8 mm endoscope. The holes were filled up between each handling, hermetically plugged at the end of the works, and camouflaged with special mastic, so that possible curious tourists could not remove the plugs. Our works have led to the discovery of the whole relieving system of the arrangement known of the pyramid of Meidum. This discovery induces several comments: First from an architectural point of view The builders of the pyramids, perfectly aware of the great weight to be implemented, were especially afraid of the falling of the empty spaces made inside the monument. In order to make up for this risk, they relied more on vaults than on flat roofs: thus, very reduced spans (0.75 m for the corridors of Meidum and the portcullis spaces of Northern Dashur) were covered with corbelled roofs. All things considered, the first use of the relieving chamber principle in a pyramid is not the well-known one which covers the « King’s » chamber in the pyramid of Cheops: known and mastered from the IIIrd Dynasty, this principle must have been used as circumstances required. It is thus possible, if not probable, that such systems were used in other pyramids. Therefore Meidum, which is a transition pyramid between the pyramids with a subterranean arrangement and the ones with a built arrangement, and between the step pyramids and the true ones, is not as rudimentary as it may have seemed: it is made of a complex built system prefiguring the sophistication of the later pyramids. Secondly from a preservation point of view Whether the causes are endogenous or exogenous, the sections opened are extremely damp and show salt formations and stone splitting. The small corridor discovered behind the window, which is isolated from the damp sections with thin masonry that is imperfectly tight, shows the same deterioration. On the contrary, perfectly closed and isolated, the chambers discovered are nearly intact. Thirdly, from an egyptological point of view The interpretation of what we discovered is outside our scope. Nevertheless, we hope we have modestly contributed to a better knowledge of the obscure period of the IIIrd Dynasty by showing that the architectural concepts were more advanced than we could assume so far. We wish we had discovered some worker graffiti that would have removed the uncertainty about the attribution of the pyramid of Meidum to Hun. Now, even if we clearly discerned red hematite lines, we did not see any graffiti. But the use of an endoscope with dim luminosity does not offer clear observation of the distant parts: some later observations with higher performance equipment would give the possibility of discovering ones. We think we have demonstrated that the study of the pyramids from a strictly architectural point of view could bear fruit. Finally, we greatly thank the Supreme Council of Egyptian Antiquities and especially Professor Gaballa for having placed confidence in us, and we hope that our work gave satisfaction. We also thank the Hilti and Olympus companies, whose high performance equipment, placed at our disposal as a favour, has played a great part in the outcome of our research • 1. The pyramid of Meidum; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 2 and 3. Original blocks of the window situated in the upper section of the north wall of the shaft and hiding the new cavity; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the new chamber discovered, taken with Olympus endoscope on the 13th of May, 1999 4. On the 25th of May 1998, Gilles Dormion and Jean-Yves Verd’hurt taking a picture of the internal part of the new cavity with the endoscope Olympus; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 5. Picture of the upper corbel ofthe new cavity taken with the endoscope Olympus; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 6 and 7. Vieuws of the new cavity; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the north chamber discovered, taken with Olympus endoscope on the 28th of September, 1999 8. North wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 9. North west corner; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 10. Floor from left to right: west wall, north wall, east wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 11. South west corner: we can see on the floor the part of split rock of the west wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 12. Top of south wall: corbels; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 13. South wall: we can see that there are no salt formations; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 14. Top of South wall: corbels; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 15. Opening of the relieving corridor: we can see the processing of the change of angle of the west wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 16. Opening of the relieving corridor in the north wall of the northern chamber; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 17. Top of the north corridor, corbels: we can see that there are no salt formations; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 18. The relieving corridor ends against a monolithic stone laid perpendicular to the slope: in the stone axis we can see clearly a vertical rectiliear brow line; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the northern relieving corridor discovered, taken with Olympus endoscope on the 13th of May, 1999.

Gilles Dormion Jean-Yves Verd’hurt The pyramid of Meidum, architectural study of the inner arrangement. civilisation pharaonique: archéologie, philologie et histoire World Congress of Egyptology, Cairo, 28th of March-3nd of April 2000 Gilles Dormion et Jean-Yves Verd’hurt, The pyramid of Meidum, architectural study of the inner arrangement The pyramid of Meidum, attributed to the first King of the IVth Dynasty, Snefru, is mainly known for the successive transformations of its outer mass. Step monument in its original design, in the tradition of the monuments of Zoser, Sekhemkhet, and Zawiyet el-Aryan, the pyramid of Meidum was built with inward-sloping sides towards the nucleus. Then an enlargement was undertaken, converting the seven-stepped pyramid into a pyramid with eight steps that were filled in with horizontal-bed masonry, which transformed the monument into the first true pyramid. Finally, the collapse and/or the pillage of these coatings, which is its characteristic shape today. Such special evolution has often been studied and described, maybe to the detriment of its inner arrangement. Owing to the limited dimensions of the apartments and the elementary nature of their layout, the pyramid looks quite simple and does not seem to pose any particular problem. A corridor leads downwards, first through the core of the pyramid, then under the level of the rocky plateau, and goes on horizontally, built in a trench hewn in the plateau. At the end of the corridor a vertical shaft leads upwards and opens in a burial chamber which is built at the level of the rock levelling and covered with a corbelled roof (see plan I). Or a great anomaly in this architectural arrangement caught our attention, and this study was motivated by its logical analysis. The horizontal corridor that connects the descending corridor to the « shaft » leading to the upper chamber has two recesses, whose dimensions are 2.60 m NS (5 cubits) x 2.10 m EW (4 cubits) and whose height from the floor -1.75 m- is equal to that of the corridor (plate I). The ceiling shared by the corridor and the « recesses » is made of a succession of lintels forming a flat roof. At right angles with the « recesses » the span of the lintels is 2.10 m (4 cubits). Covering a 2.10 m span with a flat roof is quite unusual in the architecture of the Old Empire pyramids: the builders, aware of the weight to be implemented, usually used the technique of the corbelled roof in order to cover spans more than 1.05 m (2 cubits). Considering that the span covered is exceptional with a flat roof and that the lintels do not show any significant cracks, it is hardly likely that the builders of the pyramid of Meidum took the risk of putting the weight directly on these lintels, whose span was so great, and that induces us to think that there is a relieving system above the flat roof itself. Such a device, supposed to be made with a corbelled roof according to the technique used at that time, would indicate the presence of « relieving chambers » above the « recesses ». May 1998 As part of this hypothesis, we meticulously observed the masonry in order to detect a significant detail: from the first day, in the upper section of the shaft, we discovered a bonding symptomatic of a walled aperture we called « window » (plate II). The walled « window » is 99.5 cm high and 74 cm wide at the base; it narrows into a trapezium at the top. This section is too reduced, especially in height, to be the mouth of a real corridor; on the other hand, it could be the opening of a narrow passageway for technical use. The east rising joint, at right angles with the block B3, shows a gap 1 cm wide which has no mortar and would enable the passing of an endoscope without any damage. On the 25th of May 1998, upon examination, the Franco-Egyptian working team decided to introduce an endoscope through this joint (flexible endoscope Olympus, 1.50 m in length, 8 mm in diameter, with light source and adjustable head). In the presence of Mr Mustapha El Zeiry, Dr Samir Abdel Halim, Dr Shawki Nahkla, Mr Mohsen, Mr Korani, Mr Gilles Dormion and Mr Jean-Yves Verd’hurt, the operation was executed without difficulty and a small corridor behind the walled window was discovered. The endoscope enabled us to observe that this small corridor was corbelled. There were substantial salt formations on the masonry. The floor was strewn with debris from split stones, and salt crystals that had fallen from the side walls. The corridor was estimated to be 3 m long. A series of photos was taken with the endoscope. In order to complete the observations more precisely, Dr Mustapha El Zeiry authorized to remove the upper stone B4. This operation was made on the 26th of May in the morning. The 40 cm thick stone removed showed an opening 26 cm high and 33 cmwide. Direct observation was thus possible together with photographies from different angles. I. Description a. Walled part called « window » (plate II) The four blocks B1 B2 B3 B4 that wall up the opening are about 40 cm thick. On the east side the stones are laid against the inner corbels of the corridor and badly joined with gypsum (the rising joint of the stone B3 has practically no mortar). On the west side the wall is cut as a trapezium for a depth of 13 cm. Between the block B1 and the upper joint a stone, accurately cut, was inserted. The visible piece of wood above the window is fitted for a depth of about 40 cm into the gap of the upper corbel. b. The cavity (plate III-IV) It is a kind of small corridor going north-south, straight above the lower corridor. Its dimensions are 2.80 m long, 0.75 m wide at the base and 1.44 m high. The pavement of the corridor would thus be 3.40 m above the roof of the lower corridor. The corridor is made of three visible corbelled courses. The substantial salt formations and the splitting of the stones do not enable us to know the real quality of the masonry which, however, seems quite comparable to that of the burial chamber. The top level of the last corbel (that corresponds to the upper end of the piece of wood visible from the outside) seems to correspond exactly to the level of the natural rock. The north end of the corridor, which was difficult to observe in detail (considering the distance of observation -2.80 m- and the two slabs of split stones which partially hide the base) looked smooth and even, with no visible joints and no substantial salt formations, contrary to the rest of the masonry. The opening made was closed that same day with a limestone block cut to size and joined with plaster. II. Comments The position of this corbelled device straight above the lower corridor suggests that its purpose is to relieve it. It is worth pointing out as well that if the builders had found it necessary to relieve a corridor 0.75 m (10 palms) wide, such a precaution should have proved particularly essential with regard to both recesses whose span was three times as great (2.10 m = 4 cubits). That corresponds to the hypothesis which has motivated this study, that is to say it is to be architecturally expected that both recesses should be surmounted by a relieving roof. The removing of a stone in the upper part of the window had enabled us to see a small corridor but not to enter it. After having consulted the Egyptian Antiquities, a second stone was removed in order to make a sufficient gap. The thick layer (about 25 cm) of debris strewing the floor was cleared away. The debris were sorted in order to check if they did not have any element of archeological importance. They were mainly composed of split limestone pieces and of salt formations in large amounts that had come off the side walls and the corbels. Some samples were given to the Egyptian Antiquities for analysis. May 1999 As the north side wall of the small corridor discovered was supposed to be situated less than one metre from a relieving chamber expected to be straight above the southern recess, we decided to make a hole to check the existence of such a chamber. We made an opening 16 mm of diameter in the joint of the western lower corner of the north side wall of the corridor. Easily made for 95 cm in length, this opening led to an empty space. We introduced an endoscope which enabled us to see a small built chamber we meticulously and lengthily observed, then photographed. I. Description of the chamber (subject to the restraints and the limits of an observation with an endoscope) (plate V-VI) As we thought, it seems to be exactly situated straight above the southern recess with the same dimensions (east-west: 2.10 m, 4 cubits; north-south: 2.61 m, 5 cubits). It is covered with a corbelled roof. It is made of seven courses: two vertical ones at the base, then five corbelled ones. The floor does not have any pavement, and is not even: it is made of the upper side of the three beams covering the southern recess. These beams seem to have different heights (exactly as in the relieving chambers of the pyramid of Cheops). The north wall is made of seven courses, the three upper courses seem to have successive recesses. The south wall is made of five courses; only one stone corresponds to the three upper corbels and to the north side wall of the small corridor. The ceiling ridge of the chamber seems to correspond in height to that of the small corridor, that is to say the level of the natural rock levelling. The chamber does not seem to lead anywhere. The masonry is carefully made: the beds of the courses of the north and south walls correspond to those of the existing corbels (except for the lower corbel). The chamber looks well-preserved. The side walls are neither split nor damaged as in the other sections known of the pyramid, and do not seem to have any salt formations as in the small corridor recently discovered. The floor is strewn with few debris. Only a significant block has come off the second course of the west wall. II. Comments The fact that the chamber is exactly situated straight above the southern recess, directly laid on the beams covering the recess without evenness and pavement, and blind, leads us to think that the only function is to relieve the southern recess. What surprised us most is the excellent state of preservation of the chamber. It seems that the damage due to moisture and salt, visible in the other sections that can be visited and in the small corridor discovered, has not affected this chamber at all. This fact is reassuring but raises the question of the state of the sections known of the pyramid, and of the problems linked to its preservation, namely: Has the moisture saturation of the sections visited an inevitable endogenous origin (rising damp from the ground water through the sections that are not built — the shaft, the floor of the burial chamber)? Has it an exogenous origin (moisture brought by visitors and not eliminated)? Or both at the same time? Concerned about this angle of the problem, we took particular care not to cause atmospheric exchanges between the sections visited and the virgin chamber. For this purpose, we sheathed the 16 mm opening in order to leave no gap between it and the 8 mm endoscope, and it was filled up between each handling and hermetically plugged at the end of the works. September 1999 The existence of a relieving chamber above the southern recess implied the existence of a similar chamber expected to be situated above the northern recess. In order to see that chamber, we made a hole (18 mm in diameter, 1.30 m long) without any difficulty in the first section of the descending corridor. This opening led to the north-west corner of the chamber floor; we introduced a video-endoscope and we thus observed a chamber almost similar to the one previously discovered above the southern recess. I. Description of the chamber (subject to the restraints and limits of an observation with an endoscope) (plate VII) As was planned, it is situated straight above the northern recess, with the same dimensions (east-west: 2.10 m — 4 cubits; north-south: 2.65 m — 5 cubits; about 3.50 m in height). It is covered with a corbelled roof. The east and west walls are made of seven courses: two vertical ones at the base, then five corbelled ones. The south wall is vertical and is made of seven courses. Observed with difficulty, the north wall is vertical. The ceiling ridge of the chamber seems to correspond in height to that of the chamber above the southern recess, that is say the level of the natural rock levelling. The floor does not have any pavement: it is made of the upper side of the three beams which cover the northern recess. The masonry is well made, but is not re-dressed. Under the projecting faces of several corbels we can clearly see fine straight lines of red hematite drawn by the builders. In the western lower corner of the north wall we can see a hole situated straight above the descending corridor. The stones that form the opening of this hole form an angle which seems to correspond to the slope of the descending corridor; therefore it seems obvious that it is the mouth of a relieving corridor situated above the ceiling of the descending corridor. The chamber looks well-preserved. The side walls are neither split nor damaged as in the other sections known of the pyramid, and do not have significant salt formations as in the small corridor behind the window previously discovered. The floor is strewn with few debris. However some large blocks have come off the upper corbels; one of them, situated in front of the endoscope, obstructed the observation. II. Comments The comments and conclusions we can make are exactly the same and corroborate those we previously formulated. III. Observation of the relieving corridor In order to observe the corridor whose mouth we had noted in the north wall of the chamber, we made an opening (18 mm in diameter, 0.90 m long) in the ceiling of the descending corridor, 10 metres up from its lower end, and we introduced the video-endoscope. IV. Description of the corridor (plate VIII) Its construction is similar to that of the small corridor discovered behind the window. Its dimensions seem to be roughly 0.75 m wide, 1.40 m high. Its east and west walls are made of three corbelled courses above the beams that form the ceiling of the descending corridor. The masonry is roughly made. It is well-preserved. We do not observe any salt formations. The floor is strewn with a few debris that have come off the side walls. We cannot see the south and north ends: it would seem that it covers the descending corridor for its whole length. This point will have to be checked later. We know that it opens in the south to the northern chamber previously discovered, but it would be interesting to know if it ends in the north at right angles with the initial casing of the pyramid. On the 31st of March 2000, in order to know the length of the relieving corridor above the descending corridor, we made two drill holes. The first one, situated in the corridor ceiling 19.70 m from its lower end, 2 m in depth, did not meet any empty space. The second one, made in the ceiling 12.56 m from the lower end, led into the relieving empty space. The introduction of the endoscope enabled us to see the corridor and its upper end. To the best of our judgement with an observation, the relieving corridor ends about 2.50 m up from the drill hole, that is to say about 15 m from its lower end. The relieving corridor is just as we had previously observed it further down. Three corbels are directly laid on the top faces of the beams of the descending corridor. The top of the beams is not uneven; all the beams of the descending corridor have the same height and make a flat floor in the relieving corridor. About 2.50 m up from the drill hole, the relieving corridor ends against a monolithic stone laid perpendicular to the slope. The corbels rest against this stone. It is laid on the floor (top faces of the beams of the descending corridor) with a wide joint without mortar. In the stone axis we can clearly see a vertical rectilinear brown line. We first thought that it could be a hematite line for the setting up axis, but it might actually be a fine flow mark coming from the corbels axis. Finally we can notice that the 15 metre length of the relieving corridor seems to correspond to the spot where the descending corridor is not built in trench in the ground any longer. If this relieving corridor ended at the outer face of the inner core of the pyramid, against which the first coating layer is laid, this inner core would be 80 cubits wide at the base. As before for the southern chamber, we took particular care not to cause atmospheric exchanges between the sections visited and the virgin ones. For this purpose, we sheathed the 18 mm openings in order to leave no gap between them and the 8 mm endoscope. The holes were filled up between each handling, hermetically plugged at the end of the works, and camouflaged with special mastic, so that possible curious tourists could not remove the plugs. Our works have led to the discovery of the whole relieving system of the arrangement known of the pyramid of Meidum. This discovery induces several comments: First from an architectural point of view The builders of the pyramids, perfectly aware of the great weight to be implemented, were especially afraid of the falling of the empty spaces made inside the monument. In order to make up for this risk, they relied more on vaults than on flat roofs: thus, very reduced spans (0.75 m for the corridors of Meidum and the portcullis spaces of Northern Dashur) were covered with corbelled roofs. All things considered, the first use of the relieving chamber principle in a pyramid is not the well-known one which covers the « King’s » chamber in the pyramid of Cheops: known and mastered from the IIIrd Dynasty, this principle must have been used as circumstances required. It is thus possible, if not probable, that such systems were used in other pyramids. Therefore Meidum, which is a transition pyramid between the pyramids with a subterranean arrangement and the ones with a built arrangement, and between the step pyramids and the true ones, is not as rudimentary as it may have seemed: it is made of a complex built system prefiguring the sophistication of the later pyramids. Secondly from a preservation point of view Whether the causes are endogenous or exogenous, the sections opened are extremely damp and show salt formations and stone splitting. The small corridor discovered behind the window, which is isolated from the damp sections with thin masonry that is imperfectly tight, shows the same deterioration. On the contrary, perfectly closed and isolated, the chambers discovered are nearly intact. Thirdly, from an egyptological point of view The interpretation of what we discovered is outside our scope. Nevertheless, we hope we have modestly contributed to a better knowledge of the obscure period of the IIIrd Dynasty by showing that the architectural concepts were more advanced than we could assume so far. We wish we had discovered some worker graffiti that would have removed the uncertainty about the attribution of the pyramid of Meidum to Hun. Now, even if we clearly discerned red hematite lines, we did not see any graffiti. But the use of an endoscope with dim luminosity does not offer clear observation of the distant parts: some later observations with higher performance equipment would give the possibility of discovering ones. We think we have demonstrated that the study of the pyramids from a strictly architectural point of view could bear fruit. Finally, we greatly thank the Supreme Council of Egyptian Antiquities and especially Professor Gaballa for having placed confidence in us, and we hope that our work gave satisfaction. We also thank the Hilti and Olympus companies, whose high performance equipment, placed at our disposal as a favour, has played a great part in the outcome of our research • 1. The pyramid of Meidum; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 2 and 3. Original blocks of the window situated in the upper section of the north wall of the shaft and hiding the new cavity; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the new chamber discovered, taken with Olympus endoscope on the 13th of May, 1999 4. On the 25th of May 1998, Gilles Dormion and Jean-Yves Verd’hurt taking a picture of the internal part of the new cavity with the endoscope Olympus; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 5. Picture of the upper corbel ofthe new cavity taken with the endoscope Olympus; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 6 and 7. Vieuws of the new cavity; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the north chamber discovered, taken with Olympus endoscope on the 28th of September, 1999 8. North wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 9. North west corner; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 10. Floor from left to right: west wall, north wall, east wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 11. South west corner: we can see on the floor the part of split rock of the west wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 12. Top of south wall: corbels; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 13. South wall: we can see that there are no salt formations; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 14. Top of South wall: corbels; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 15. Opening of the relieving corridor: we can see the processing of the change of angle of the west wall; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 16. Opening of the relieving corridor in the north wall of the northern chamber; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 17. Top of the north corridor, corbels: we can see that there are no salt formations; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. 18. The relieving corridor ends against a monolithic stone laid perpendicular to the slope: in the stone axis we can see clearly a vertical rectiliear brow line; photo Gilles Dormion and Jean-Yves Verd’hurt, all rights reserved. Pictures of the northern relieving corridor discovered, taken with Olympus endoscope on the 13th of May, 1999.