(21) Having examined, as far as possible, the methods by which the obelisk was separated from the surrounding rock, we will consider by what means the obelisk was detached from its bed and got into a position in which it could be handled and transported.

It might be remarked that this particular obelisk has not been transported; there is no doubt, however, that the man responsible for the work had quite definite ideas as to how he was going to perform the feat. 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.

There seem to be two methods by which the obelisk could be detached from its bed; the snapping off of such an obelisk in the manner mentioned in section 19 being out of the question.

(1) By undercutting the obelisk from both sides to a certain extent, say a quarter of the breadth from each side, and either detaching it by a series of very large wedge-slots (as was done all over the quarries for medium-sized blocks), or, if the Egyptians used wooden wedges, expanded by the action of water, by one long wedge channel on each side of the obelisk. These could be wetted by flooding the trench with water, but before this could be done, the trench would have to be divided into compartments by, say, mud-brick walls to prevent the water running down to the deep end, leaving the pyramidion end dry. In this case a large allowance would have to be made in case the granite did not break evenly across between the wedge-channels. The great objection to this method is the risk of the obelisk breaking across owing to uneven strains set up by the wedges; it will be seen, in section 43, that the obelisk can only just support its own weight when in a horizontal position. If this method were employed, before the obelisk could be moved, it had to be raised off its bed to pass ropes round it. This could be effected by levering from both sides of the obelisk—using the outer trench wall as fulcra—and gradually rocking the obelisk higher by packing below it at each tilt. 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. Since the obelisk would have to be tilted from both sides, a good deal of rock would have to be removed from the south side of it before the levers could be used.

(22) (2) By completely undercutting the obelisk. In spite of the slowness of the work I am convinced that the obelisk was completely undercut, most likely by hand pounding, since the expenditure of copper chisels would be terrific, and the idea, in this kind of work, seems to be to economise as much as possible on copper. It would be packed by wooden blocks or stone as near the centre as is consistent with stability, and in as few places as possible. Ropes would then be passed round the obelisk, each going several times round and being brought forward from below to anchorages in front. It is here that the details of this method assume such great importance; it must be remembered that, if the obelisk weighs 1170 tons (allowing a margin for the roughness of the undercutting below), and lies on its side on a hard bed, then the horizontal pull by ropes necessary to turn it over on to a new face will be half the weight of the obelisk, i. e. 585 tons. This would need 13,000 men, if a man pulls 100 pounds. I do not see how such a number could possibly be put on to this work. Figure 6 shews the obelisk supported on its packing, the section here being at the centre of gravity, and the outer edge of the packing being 1 metre from the centre of the obelisk on each side. To pull it over by horizontal ropes would need 8000 men, which still seems more than is practicable. It is possible to reduce the number of men required to turn the obelisk over by means of levers working off the north wall of the north trench, which seems to have been deliberately left for that purpose (cf. section 5).

(23) By using, say, 30 21-foot levers with a mechanical advantage of six to one, as described in the last section, the obelisk can be made to turn slightly about N (see fig. 6) so that the packing P can be removed and perhaps replaced by sand.

About N the moment of the force at the bottom of the lever is to that of the weight of the obelisk acting at its centre as 7:2 (by scaling off the figure), so that the moment at the top of the lever to that of the weight will be 42:2, or 21:1. Let the number of men per lever be n. {25}

Then 30 ×21 ×100 ×n =1170 ×2240, which gives the number of men as 42, or 1260 men in all[9].

I have taken the amount of undercutting in figure 2 as .75m. at the centre of gravity; it would increase as far as 1.00 metre at the butt.

As soon as the sand had replaced the packing, the rock A?B would be removed by burning and wedging until it sloped down as much as possible from the level of the bed of the obelisk. I had not sufficient funds at my disposal to examine the levels of the rock to the centre of the valley, so I have to be rather vague as to what distance the obelisk was rolled out[10]. The obelisk would then, when the sand flowed out or was removed, take up a position as shewn in the dotted section.

Then, about Q, the moment of the horizontal force of the ropes round the obelisk to the moment of the weight will be, from the figure, as 9 to 2, so if n be the total number of men required to pull the obelisk over, then (n ×100) =(2 ×1170 ×2240)/9 which gives 5824 men as against the 8000 men which would be required if the levers were not used. It is an enormous number, but I do not see how they could manage with less.

A bank of sand just in front of the lower edge of the obelisk would make the second turn an easy matter, and if from thence the obelisk is rolled downwards on soft sand, I think that the 5824 men will still be ample, as the sand can be undercut in front of the edge and so make the rolling approximate to that of a cylinder.

(24) As to the size of the ropes required for the rolling out of the obelisk, all we can do is to obtain a very rough idea as to it. If they spread the men out slightly fanwise, I do not see how they could have used more than 40 ropes. The strain per rope will be, as we have seen, (2/9 ×1170/40) =6.5 tons per rope.

The rope used was probably the very best palm-rope, newly made. The safe load which can be put on coir rope, which is of about the same strength, is given by the formula: Load in cwts =(Circumference in inches)² divided by 4 (Military Engineering, 1913, Part III A, p. 49). Substituting, we have (6.5 ×20 ×4) =C² which gives a circumference of 22.8 inches and a diameter of 7¼ inches. If such a rope were used it would require handling loops on it.

(25) Before leaving the work at the quarry, it remains to be seen how the chiselling of the wedge-slots was done. The apparent impossibility of cutting granite with a copper chisel has struck every student of this question. Many suggestions, some of them grotesque, have been put forward to explain how it might have been performed. Gorringe, in his Egyptian Obelisks, {26} boldly assumes the knowledge of steel. To my mind, the reasons against this are, first: the knowledge of steel would have soon resulted in its use being widespread for daggers, swords and, above all, razors; secondly, it would have had a special name, since its properties are so different from iron. Now all the ancient names for metals have been accounted for, none of which could be applied to mean steel. If we translate Benipet as ‘steel’, then we have no word for iron.

Gorringe’s assertion that iron and steel tools would have disappeared by oxydisation in a few centuries is not borne out by excavations. We know, from the scanty mentions of iron, that it was not very generally used, but quite a number of iron tools of late Egyptian date are now known, and I have myself taken out an iron bill-hook from the filling of a Roman or Ptolemaic grave which was hardly rusted at all, and in the Cairo Museum there is an iron fork of Coptic date from a depth of 5 metres in the sabÂkh of Tell EdfÙ which is almost like new. If the ground is dry and free from certain chemicals, objects such as iron, wood, linen, papyrus, etc., will keep indefinitely, whereas, in unsuitable ground, even copper will disappear and leave no traces, except, perhaps, a blue stain. If steel had been in anything like common use, we should surely have found examples, either in graves or in town sites like KahÛn or Tell el-?Amarna. PETRIE, in Tools and Weapons, pl. VI, 187, cites a halberd of iron dated to Ramesses III; had steel been known, we should have expected it to be of that rather than iron. An examination of such broken iron tools as can be spared might give us definite information one way or the other, as steel, though it may lose its temper, will not turn into iron, however long it is left, and should be easily recognized by a micro-photograph.

On the rocks of the Wady HammÂmÂt, the following inscription is to be seen, together with others having the same title (GOLÉNISCHEFF, Hammamat, II, no. 3, and COUYAT et MONTET, Les inscriptions hiÉroglyphiques et hiÉratiques du OuÂdi HammÂmÂt, in MÉmoires de l’Institut franÇais du Caire, vol. XXXIV, p. 54):([glyph])

The determinative [glyph], sometimes written [glyph], seems to suggest iron tools in general, and we are hardly justified in deducing from this that the chisels for cutting granite were necessarily of iron; it is very likely, however, that the wedges were of iron.

(26) The suggestion, put forward by Donaldson, that the Egyptians softened the granite by chemical means before using the chisels on it, is not worthy of serious notice, as a glance at the tool marks shews that the granite was quite hard, and behaved in exactly the same way as it does under modern tools. His other suggestion, that the granite was first pounded to render it more workable, cannot be accepted as the explanation, as how did they pound the bottom of the wedge-slots?

A far more reasonable suggestion is that the granite was cut by chisels of dolerite or similar {27} basic rocks. Mr. Firth tells me that, except for the grinding of the cutting-edge, they occur naturally in the Wady Alaqi. A series of trials with such a chisel left me entirely unconvinced, the more so since many of the old chisel-marks shew that a narrow-edged tool had been used.

From my own experiments, I can believe that the Egyptians could have cut granite with a copper chisel, but more time is spent sharpening the tool than in cutting the stone, and the expenditure of metal would be appalling in any but the smallest works, but I cannot admit that copper tools, as we know them, could have ever been used to cut hard quartzite, which gave the Egyptians no special trouble, if we judge by the huge chambers which they cut, polished and transported, as in the case of the burial chamber in the Hawara Pyramid.

It has also been suggested that the copper chisels were fed with emery, but anyone who has handled a chisel will appreciate the impossibility of feeding the tool with emery; on the other hand, emery may well have formed the basis of the polishing process, and have been regularly used in stone drilling and sawing.

(27) How, then are we to explain this problem? Much as I hate to admit it, I am driven to the conclusion that the ancient Egyptians possessed some simple method of tempering copper to the hardness of modern tool-steel[11]; even now copper with 2% of alloy may, by heavy hammering, be brought to the hardness of mild steel. This has been suggested by many writers, and examples of tools are known—Wilkinson quotes one in volume II, p. 255—where the malletted end of the chisel was worn by the blows, but where the point was sharp; of course that might be explained by the fact that it had just been re-sharpened, but I have myself seen a chisel where the cutting-edge was chipped in the same manner as a modern steel tool instead of being burred. I was unable to purchase this specimen, but I tried the point with a knife, and was able to scratch it as I could any other piece of copper; the temper, therefore, must have been temporary (cf. WILKINSON, Manners and Customs, vol. II, p. 255, and PETRIE, Arts and Crafts, p. 100).

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.

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.