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Comments
Set 7, posted March 20, 1999
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Question:

If I were given the job and the resources to do it, what better way than to use water?
  1. They obviously had the shipbuilding technology to transport such items, so they could reverse this procedure and build a dry dock at the site.

  2. Provide the monolith with flotation collars at optional locations. The collar should be located at just overcenter (lengthwise) and the secondary flotation collar located toward the base.

  3. Close the container and fill it with water and when the desired elevation is achieved, flood the base.



Dennis Scott-Jackson
Burnaby, British Columbia



Response from Roger Hopkins, stonemason:

Dennis, the Egyptians were really great at building canals and dams, but they seem to be lacking in putting all the hydraulics into transferring water from one place to another. It's doubtful that they would have been filling chambers with water. To use this flotation idea, they would have had to have mastered moving great quantities of water, because no matter what they built it would have leaked quite rapidly.



Question:

I read your dispatch about the pulling progress. (See 'Pulling Together'.) If the pullers cannot maintain the dragging, then maybe the approach is just a few feet at a time. Try anchoring the ends of the ropes, then attach ropes to the middle and pull perpendicular. You increase your mechanical advantage. Your advantage finally drops to just 2X when the ropes hit 30 degrees from the direction you are trying to pull (at 10 degrees it's more than a 5X advantage, 20 degrees it's 3X—try the math).

Andrew Kulich
Rochester, Minnesota



Response from Roger Hopkins, stonemason:

Andrew, I agree with you that there is a lot of mechanical advantages to pulling rope perpendicular, but in my own personal opinion, I believe that they only pulled the obelisks very short distances. They would bring the obelisk by boat as close as possible and then they would have probably used rollers and a very firm rope—a combination of rollers and levers and rope—pulling—because it's a little easier to control. If you're depending entirely on ropes, they can act unfavorably at times.



Question:

After carefully observing the obelisk, it seems as if it was carved after being raised. It is very possibly easier to raise the obelisk in an "un-careful" state (not wanting to damage the carving) using a vertical drop. Being pulled carefully by rope over the drop (as seen in many Egyptian demonstrations), the obelisk would be pulled and standing at a vertical state.

(name witheld by request)



Response from Roger Hopkins, stonemason:

It's always best when you're carving into a block of granite to be working on the flat. So, it's probably likely that they did the carvings and rotated it on the ground. On the vertical, you could do some changes there, but it requires a lot of staging and it's more difficult work when the granite is in a standing position. As for being careful, they would had to have been careful whether it was carved or uncarved, because they went to a lot of trouble to get that block of stone there.



Question:

You almost had it the first time. Why couldn't you raise it with oxen? I would suggest the A-frame to be tilted more towards the pulling team from the start or set up two shorter A-frames in a series.

(name witheld by request)



Response from Henry Woodlock, Whitby Bird & Partners:

You are right. When the rest of the team did their first attempt, A-frames in series would have helped. However, when you consider the largest obelisks, the use of A-frames becomes less appealing. The forces involved require enormous frames. The key to using this technique is getting elevation height above the object and reducing the force required by tilting the obelisk to a steep angle first.



Question:

As far as I could tell from your program, the problem is essentially one of controlled descent. Two methods were used, and a combination of the two seems to be reasonable: A very steep ramp (steeper than that used in the program), with raised blocks built into the ramp that guide the sled in its descent. These blocks could even be placed at an angle or shaped for the purpose of catching and guiding the sled. It would seem that these blocks, or even the whole ramp structure, could be reused, so it's conceivable that most of the work that you would have to do in raising an obelisk would be a matter of fabricating stonework that the Egyptians had on hand from past projects.

Markers would have to be placed at the runway at the top of the ramp to guide the sled; the blocks that physically guide the sled will, of course, be buried in the sand used to control the descent of the sled. The sled would be pulled onto the bed of sand to the point of balance, the sand would be released, and the sled would slowly slide down the (very steep) ramp. The descent is controlled by a combination of sand removal and support ropes from behind. The bottom of the obelisk could be fitted into the turning groove in this manner. The sled runners, the height of the block, the location of the turning groove, and the base of the obelisk would have to all be coordinated, but this should not require any great feat of math (not that I pretend to be an expert in either math or the ancient Egyptians' grasp of it).

Anyway, setting the base of the obelisk, I believe, is a matter of a sand-controlled, block-guided descent down a very steep ramp to a pre-measured destination. The steeper the ramp, the better (I would guess), because this would put the obelisk at such an angle so that getting it upright would be easier.

Once this was done, many possibilities present themselves. A long structure could be built at a right angle from the top of the obelisk before it is erected: It would look like an inverted "L." The beam perpendicular to the obelisk would have to be supported from the end of the beam farthest from the obelisk to the base of the obelisk, creating a triangular structure laying against the side of the obelisk and attached to it; the widest part of the triangle at the top of the obelisk and a pointy end at the bottom. (The obelisk itself would form one of the longest sides of the triangle, with its base at the most acute angle of the triangle at the base of the obelisk.) I don't know if the Egyptians from that period understood the idea that a triangular brace will make a structure stronger, or if they had material which would make such a structure possible.

Assuming that such a structure is feasible, it would be attached to the obelisk before it was lowered into the pit. The obelisk would be lowered as before, and the sandpit would be disassembled around the obelisk and its attached structure once the sand was drained. Many ropes would be attached to the end of the beam perpendicular to the top of the obelisk on the end of the beam farthest from the obelisk.

Someone would then have to climb out onto the end of the beam and start hoisting up sandbags. As a practical touch, a little seat could be built onto the end of the beam for this purpose. This would add comfort and efficiency, because I contemplate a slow pace in this phase—about 10 to 20 pounds at a time. Since we are talking about such huge weights, this would take a good deal of time, but by the same reasoning, a platform with three men could work pretty steadily at the end of the beam.

This method would, of course, present the problem of enormous torsion at the base of the obelisk if the counterweight were not balanced along the midline of the obelisk. Also, if the whole contraption were not balanced properly, the structure would likely collapse; it is not built to take lateral strain in one direction. Lateral strain in two directions, however, would have the net effect of balancing the whole contraption. The balancing could be done in the following manner. Ropes would be placed like guy wires on each side if the obelisk and structure. These would be "paired" ropes, two ropes to each support. The ropes could then be twisted with large poles to control the lateral movement of the obelisk and the counterweight. Further, the ropes could be stretched over A-frames to make them more manageable. Someone could "eyeball" the structure from a distance, and with either runners or hand signals, fine-tune the raising of the obelisk.

The whole would, of course, have to be supported from behind in order to keep it from toppling forward once the counterweight went past the point of balance. These support ropes would be pre-twisted in a manner that the tension on them could be slowly released. Once the obelisk was upright, the sandbags would be cut away one by one, and the tension on the ropes slowly released, and the obelisk would be left standing once the structure was cut away from it.

A theoretically similar method to the above involves the use of A-frames. Instead of one A-frame, however, an array of A-frames would be used, much in the same manner as a very large team of horses is arrayed from a very heavy load. Some of the A-frames would be closer to the "load" and some would be farther away, but in the end, all would pull in the same purpose. Again, lateral guide ropes would be twisted to control lateral movement, and sandbags would be used to pull the A-frames.

I really think this would work. The ropes could be attached to the obelisk and then stretched over the A-frames. Sandbags could then be attached to the ends of the ropes after they are stretched over the A-frames. Again, the sandbags would be attached one at a time. A few bags could be attached in the beginning to make the A-frames stand up, and then two people could be stationed at each frame to hoist sand bags. Note that this would not require cruelly heavy labor on the part of anyone, and the methods used would be only moderately dangerous. Further, it would not require huge crews, and could be accomplished with about a hundred people (assuming that each frame can pull a ton).

The A-frames could probably not lift the whole obelisk at once, and would have to be moved several times in order to bring it all of the way up. The obelisk, of course, would have to be supported from behind each time it was lifted a little. This would probably change their relative positions, and they would have to be initially spaced so that they will not interfere with each other throughout the whole of the project. Again, the ascent of the obelisk would be controlled laterally and from behind with twisted ropes. Once the obelisk was upright, the sandbags would be slowly cut away from the A-frames and the tension on the ropes would be released.

To sum up, I would raise the obelisk by sand-controlled and block-guided descent down a very steep ramp and then use a large counterweight balanced by ropes to help in raising the obelisk. Or, I would use several A-frames to slowly pull the obelisk into position once it was placed in the turning groove by the controlled descent described above. Again, sand, and not brute human pulling power, would be used as both the force and control needed to raise the extremely heavy obelisk once it was in the turning groove.

Marcus Vise
New Orleans, Louisiana



Response from Henry Woodlock, Whitby Bird & Partners:

The difficulty with the sand method is twofold. First, there is the size of the construction required to get the height of the ramp. Sandbanks are naturally at quite a shallow angle, and if it is banked up high enough for the big obelisks, the pile would cover an enormous area. I sometimes feel that the implications of this have not been considered. In the temples, monuments are closely spaced and all would be covered in sand during the erection of the latest obelisk.

The second difficulty with sandpits is control. How do you let sand out of a chamber evenly to avoid the obelisk going off course? We saw the difficulties on the last NOVA program, and that was with a tiny obelisk. A 'sand-box' has been suggested by some archaeologists. The suggestion has been that mudbrick was used to enclose the sand. I remain skeptical about the ability of mudbrick walls to resist the lateral pressures of the huge height of sand. Sand control makes sense to me for cuboid heavy objects like a sarcophagus or some statues, but not for the shape of the obelisk.

The raising methods you describe are all feasible from a steep angle. The reason I hesitate to use an A-frame to pull the obelisk the last few degrees to vertical is the risk of overturning the obelisk. It may be easier to pull in a less direct way at the front by 'swigging' (pulling horizontally on anchored vertical ropes) and brake the obelisk at the back to achieve fine control.



Question:

How were the mummies wrapped?

Alexis
Reading, Pennsylvania



Response from Rob Meyer, NOVA:

Alexis, that's an interesting question. I would suggest checking out Mummies of the World, part of NOVA's Web site Ice Mummies of the Inca, in which we explore that very issue.




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