Reginald Engelbach

“ Here the obelisk is very long and thin and has an impossibly short pyramidion, but in any case such a problem can only be solved by one who has had previous experience, not only of the friction to be overcome in the transport of large blocks, but of the nature of the ground to be traversed. ”

“ It may be that, since in all the obelisks we know of, whose taper does not vary to any great extent, can be supported anywhere, the Egyptians never had a case of such a monument breaking by its own weight.
Another interesting point arises in connection with this, and that is, since in obelisks (and all beams) of the same proportion, the bending stress due to their own weight depends on the linear dimension, and therefore the fact that a granite scale-model does not break will be no indication that the monument itself will not break when similarly supported. ”

“ It might be remarked that instead of having a method of greatly hardening copper, the Egyptians might have been able to temper iron. The experiments on iron and its properties during the last century have been innumerable and, had there been a method, apart from the introduction of carbon, of tempering iron to a very great hardness, I think that it would certainly have been discovered by now. In our present state of knowledge, it is best to leave the subject as an open question. ”

“ It would be almost impossible to lever up a large obelisk, close to a pylon, on an ever-increasing earth slope, and it could not be ‘rocked’ up as it would slip out of the notch. (2) Pulling by head-ropes, with or without the aid of a strut or ‘raising-lever’, would be useless until the obelisk was almost upright, even if it was done from a high embankment. ”

“ In any case I imagine that the workmen would find it false economy to narrow the trench too much, as the cramped position would make the work go more slowly. I suggest that the reason for the occasional narrowings is that one party knew that their spell was coming to an end at a certain level, and finished it quickly, knowing that someone else had to continue the deepening.
It will be noticed that the top-dressing, as seen at the pyramidion, plate IV, no. 1, and the butt-end of the obelisk, is less regular than the pounding work in the trench ”

“ The obelisk is then pulled up on rollers, base foremost, until it just overhangs the slope A. The funnel, previous to this, is filled with the finest Aswân sand, which has very little cohesion in its particles, banked high against the butt of the obelisk. The sand is then very gradually removed from the tunnel, thus letting the obelisk slowly down on to its pedestal. In this process, men would descend with the obelisk until the masonry portion of the tunnel was reached. ”

“ Of modern theories two seem to be popular; the first suggests that the obelisk was laid flat, with one side of its base just above the notch, which in nearly all cases runs along one side of the pedestal, and that it was gradually levered up, and at the same time banked from below, being assisted when it had become sufficiently high by pulling with head-ropes, and similarly checked by ropes when on the point of tilting over on to its base. ”

“ It is very likely that water was poured on the hot stone to make it break up. This method of heating and chilling is used on the granite in India at the present day. Traces of burning are seen in the obelisk area at A and B on plate V, no. 1. Such a vast amount of stone has been removed in the neighbourhood which shews neither wedge nor chisel marks that, without the proof of the burnt brick and stone, we should have been driven to the conclusion that burning was the method employed [1] . ”

“ The most serious flaws in the obelisk are those lettered a, b, c, d, k, m, o and p; any one of these would give one seriously to think as to the advisability of abandoning the work forthwith. {7} Fissure a meets fissure b and settles, once and for all, that the pyramidion must be set back at least half a metre. Fissure c is even more radical. Fissures d, e and f all seem to have connection with one another and make a considerable reduction in width necessary; those between k and m carry a similar warning on the south side, while m and o necessitate shortening the obelisk from the butt end. ”

“ The width of the embankment or track, of which there are many about the quarries, need only be about one-third the length of the obelisk, and the tendency for the obelisk to roll in a circle would be to a large extent neutralized if it were of soft sand, where the heavy end would sink in to a greater depth than the point end. ”

“ Although it is the largest obelisk known (pace the phantom 108 cubit obelisk of atshepsôwet) , the old engineers have actually moved even heavier and more unmanageable blocks: the colossus of the Ramesseum and the colossi of Amenophis III at Thebes. If we can solve the ancient method of dealing with this particular obelisk, we can the more easily understand how the others were dealt with. ”

“ A gigantic tower of wood, known as ‘Fontana’s Castle’, was erected over the obelisk, being made of compound wooden struts of a metre square in section. From the cross-beams of the tower pairs of blocks and tackles were attached at four points along the obelisk, which was protected by matting and planks. The obelisk was first raised sufficiently high, being wedged as well from below, to enable a ‘cradle’, or platform on rollers, to be introduced underneath it. ”

“ The purpose of this evidently was to raise the great block by sliding it on its side up the slope and then to tilt it upright by gravity over the head of the slope. How the mass would be turned we have nothing to show, but probably the simplest way, by gradually removing earth, would be followed. By next ramming earth behind the obelisk as it lay on the slope, it would be quite practicable to force it forward into an upright position. ”

“ Boning rods are a set of equal, usually T-shaped pieces of wood. One is held upright at each end of the surface which it required to straighten. A man standing at either end, if he sight along the top of these boning rods, can see if a third boning rod, placed anywhere between them, is above or below the line joining them. Thus the surface can be tested anywhere along the obelisk until it is made to slope evenly down along its whole length.
Boning rods for dressing moderately large blocks of stone are shewn in PETRIE, Tools and Weapons, plate XLIX, B 44–46. ”

“ What it does, if the pulling is not very even and square, is to pivot on one of its corners at the beginning or end of its first rock, with what would be disastrous results in a large obelisk. (37) The more usual explanation as to how the erecting was performed is that the obelisk was pulled on rollers up a long inclined embankment until it was at a height well above the centre of gravity of the obelisk. ”

“ A square funnel is first built round and above the pedestal on which the obelisk is to stand (see plate VIII) , leaving a space about half a metre high, and one and a half metre wide, clear over the edge of the pedestal, to lead out to a tunnel. The sides of the funnel, which are {39} of smooth masonry, are set at a slope so that the obelisk on being lowered into it can lie against the wall of the slope without passing its dead-centre and coming of itself to an upright position. ”

“ Now nearly all the ancient wedge-slots appear perfectly smooth inside—just as if they had been polished. This would be a disadvantage in using feathers, as there would be a greater tendency for them to jump out at the first blow. Nothing seems to be gained by polishing. Personally I favour the assumption that the Egyptians used the plug-and-feather, but the question is best left open for the present for lack of conclusive evidence. Photographs of two iron wedges from the Ramesseum are given in PETRIE, Tools and Weapons, plate XIII, B 16, 17. ”

“ The blocks of stone were removed and the vessels, being thus gradually lightened, received their burden.” If this was so or not, it certainly was not the method by which the obelisks were brought from the Aswân quarries to the bank. No trace of a canal of this sort is to be seen, though there are plenty of traces of enormous embankments. ”

“ I am very sure that, at the end of the tunnel, no constant flow will occur, even when the sand is being pressed down by a 1168‐ton obelisk; it is more likely that men would have to remove the sand from half-way along the tunnel.
The bottom of the funnel would have to be slightly larger than the base of the obelisk, so as to be able to remove the sand, stones and brick fragments which might have come down with it.
If all went well, the obelisk, when it touched the pedestal, would lie against the near wall of the funnel with its base engaging in the notch. ”

“ The fact that it is in black paint on very dark red weathered granite has made it very difficult to photograph. It appears to begin with a date, and to have a number in the middle, but there is no name of a king.
(20) At the top of the upper quarry-face there is what seems to be the bed from which a monument, very probably a small obelisk, of 7 metres long has been extracted. The bottom of the trench can still be traced where the work has been divided up into grooves of similar width to those in the obelisk trench. ”

“ If this is the true solution, it is probable that the knowledge died out when the use of iron and steel became general, as its value in not producing sparks could hardly have been foreseen. It is not surprising therefore that the knowledge died out when it was no longer a necessity. ”

“ Assuming that, with rammers, the men can extract 8 millimetres in an hour in each quarter of their double-foot task, then the time taken to complete the trench, with an extra metre for undercutting, will be that of working it at its deepest part, that is to a depth of 4.2 + 1.0 metre, and will equal (4 × 5.2) / (.008 × 12 × 30) months of twelve hours per diem = 7.22 months.
Before leaving the subject of time taken, we might apply this calculation to the obelisk of atshepsôwet, assuming that it was detached in much the same way. Here the deepest part of the trench is 2.40 + .75 metre [8] ”

“ Assuming that only half a metre was undercut from both sides, it would require 30 12‐inch tree-trunks going down three feet into the trench (properly packed) , and projecting 18 feet above the trench, being used vertically, with 70 men pulling on ropes attached to the top of each lever. The strain set up would be about 1000 pounds per square inch, which is well within the {24} powers of ordinary coniferous wood as cypress. (I assume that a man pulls 100 pounds.) The more undercutting performed, the less force would be required to rock the obelisk. ”

“ The great advantage of rollers is that comparatively little space is required and a minimum of pulling force; its disadvantages are that there is always a risk of the rollers becoming jammed, and that, even on a slight incline, the obelisk is liable to get out of control.
As to the sizes of the rollers required, I can only say that the top of the fallen obelisk of atshepsôwet now rests on 20 cent. diameter pitch-pine rollers, spaced one metre apart, and there is not the faintest sign of crushing. The worst stress with the Aswân obelisk might rise to 11 times as much as the example cited. ”

“ The reason seems to be that, given a moderate sized block and plenty of men, the progress would be quicker, as the sled does not need the constant adjustment and attention which is required by rollers. As we have already remarked, the friction renders the use of sleds alone impossible for a large obelisk (cf. section 31) , so, since it appears that obelisks must have been brought into the temple precincts endways, there is no other means we know of other than rollers. ”

“ Let us assume that this method was to be used for the Aswân obelisk. I think that the largest levers practicable would be 15 metre tree-trunks used with a mechanical advantage of 10 to 1. Not more than 30 levers could be used on each side of the obelisk. The number of men required to raise the obelisk can be found to be about 56 per lever, assuming that they all heave at the end. I hardly see how such a number can be put on a horizontal lever unless we assume that a cross-baulk is attached along the ends of the levers and the whole loaded with stones. ”

“ Levers must have surely been familiar to the Egyptians; the constant import of tree-trunks from Syria would furnish them with the material, and a hundred occurrences in every-day life, such as extracting a stone with the point of a hoe would suggest to them the application. ”