floating stones

[Norman Albers]

A friend of mine, a dental technician, offered an interesting answer to the question of how people thousands of years ago assembed large stones to construct pyramids. A different friend who did heavy-duty cement work like in boring nuclear test holes years back, said he thought we have a certain limit of weight we can lift with modern cranes and that some of the work building Mayan structures was challenging to that standard. The bright idea (?) is using water floatation, or displacement; Dora thought water was available nearby. Thinking about this, many rocks have specific gravity 3-4 times that of water. A cubic foot of water weighs 62.4 pounds, so a 600,000 pound stone displaces, in the nautical sense, about ten thousand cubic feet. This would be the displacement of a barge, say, 30' square, at a depth of 11'. FURTHERMORE, could one not suspend the stone beneath the barge and so gain an extra displacement and save 30% of the effort?

[SkepticLance]

Certainly transporting stones by barge makes good sense. It has been suggested that many of the stones at stonehenge must have been carried this way.

 

Of course that does not solve the business of getting the stones into place up a pyramid. I think we are still dependent on earth ramps and lots of people pushing over rollers.

[Norman Albers]

Babe, I hear you! I rebuilt a player piano a bit more massive than most. Built in the Chicago brick sit-house style, it was perhaps 1400 pounds total. When the center of it hung on a low threshold, two of us could not slide it. Thus I learned to meditate on rollers, yup. This was an upright piano; I have pictures of the Steinway factory in 1905 or so, NY, USA, several square blocks with four or five stories and steam from the basement piped throughout. Outside are teams of four and six horses to handle drayage of grand pianos. I have been privileged to rebuild a handful of these. I'd rather avoid the submersion. I work with hot-pot hide glue, as they did. {Yes, glue factory}.

 

My friends were thinking that water was flooded actually into the pyramid. The wide base has the strength of a dam. I could imagine two separate but connected chambers to act as locks. If one were filled, then you could open the connection to get halfway up, then you'd have to pump (or carry) the other half. Then again, I can imagine lots of things. If an aqueduct delivered water high up it would be a free lift. Please be easy on me. My cement-working friend argues the space-beings had to do it.

[SkepticLance]

An ancient Egyptian hydraulic lift. That actually could work. I am not quite sure how, but I am sure a competent engineer could work something out.

[Norman Albers]

Thanks, Lance. Given a small army of laborers a "pump" could be a major "bucket line". If there is anything to this it should become evident in the structure itself, or, like, the aqueduct. What did the Egyptians do? (I have built hydraulic ram pumps which are a very cool momentum transfer device.)NEWS FLASH: Amazingly this week's issue of Science News features the plans of physicists to use muons to probe the structure of the large-looking Pyramid of the Sun at Teotihuacan.

[SkepticLance]

I would imagine something like a water tight lift shaft. A gate at the bottom is opened to float a barge in, and then closed and sealed. Some technique, whether bucket chain or other, is used to fill the shaft with water, and the barge floats up to the required level. As the pyramid gets higher, the shaft gets built up accordingly.

 

There could be a problem with stresses due to water pressure at the bottom of the shaft. If the shaft was 100 metres high, that represents a pressure of 11 bars at the base, or 250 pounds per square inch. Could ancient Egyptians build to resist that?

[Norman Albers]

Consider the shape, it's like an earthen dam profile with a broad foot. . . . . . <Could they have been storage? From the picture the one at Teotihuacan is more than 50 meters square. >

[MrMongoose]

Surely a water tight pipe the width of a pyramid rock and the height of a pyramid is more of a feat than a pyramid for an egyptian architect?

[Norman Albers]

I agree. There was not polyvinyl chloride, and soft-metal pipes won't carry much pressure. We used Bentonite clay to slow loss in our fair-sized pond.

[SkepticLance]

In today's technology, deep sea submersibles use flat lead plate as seals in joins. Normal rubber seals cannot tolerate the high pressures.

 

I think it rather likely that the Egyptians had lead. After all, the ancient Romans used lead pipes. Perhaps blocks of rocks sealed with lead beaten flat might have been used? The lead would be recovered when the shaft was dismantled.

[Norman Albers]

Certainly, Skeptic Lance, lead is a low melt temperature. Interesting to hear your knowledge. For 25 years I've had the same kitchen sink, used when I got it. I never learned about silicone grease on faucet O-rings, and always got one size too small. It was snug in the slot, but lasted only two years. Turns out I sized wrongly as is obvious when you 'mike' it. The right-size O-ring is a bit loose in the slot; even the inner part of it is compressed, and the whole thing gets nice and tight and I could hardly turn it until I figured out, a few days later, to ask about appropriate grease.

 

I read this past season about one of the South American civilizations whose people built canals and aqueducts and the water deposited so much calcite that it sealed and kept building them higher and higher. . . . . . HERE IT IS: Scientific American, Oct.2006, a beautiful feature article on the pre-Aztec hydraulic engineeering in southern Mexico, like the Tehuacan Valley.