Molten Stone Walls of Scotland

I remember seeing an article on the net,several years ago,where a scientist tried to melt a duplicate wall using charcoal and high velocity air.

He figured that the sea breeze may have provided the extra air to the charcoal.

He only succeeded in melting a very small portion.According to him,it would have taken more than all of the forests in Scotland to melt the walls that we see today.

And the search go on for the real answer.

Did you check out my link,where they are using a solar reflector to melt stone?

It would be easy enough to make a hyperbolic reflector with their level of technology.

As I said,the focusing effect was probably discovered by accident,or maybe "A DENT" in a shield,lying on the ground that started a grass fire.

The Sun Stone was probably also discovered by accident.

https://www.marineinsight.com/maritime-history/how-vikings-used-sunstones-for-navigation-at-sea/

The rear arm-rest in my car was melted by a SUV parked next to it in the parking lot.It did not flame up,but it melted it totally.I got back just in time.

The curve of my windows,the curve of the SUV windows,the distance between us all came together by chance.

Sheet happens!

Back when I was teaching physics, I had a two foot diameter glass parabolic front-surface mirror. Simply holding the mirror in my lap I did most of those things. I could cut a soft-drink can in half in somewhere between 5 and 10 seconds, BTW using asbestos gloves and gas-welder's goggles.

There a parabolic mirrored building in the Uk, that’s causing quite a bit of trouble... guess it wasn’t throughly thought out....

So with about a 1 square meter Fresnel lens an unidentified rock had a melted part about a US dime size (~2.5E-5 m^2) melted area in 15 seconds. A steel nail took 30 seconds to melt (plastic state, not fully liquid) while resting on what looked like the same rock. Without the use of a Fresnel lens ancient people during the iron age smelted far larger pieces of iron for casting from a liquid state using fire.

While it is possible to use sun light to vitrify parts of a wall, I don't believe this is the likely technique used. It would certainly take an exorbitant amount of time and patience to vitrify with reflected light a whole wall of any dimension let alone a wall that is part of a fort.

Remember, Anglo-Saxon glass manufacturing and working did not use sunlight in production.

Somewhat off topic, but I recall a party trick from the workshop mob at Parabadoo where they would weld rocks from the mine together.

Both with oxy and even arc welding.

Very rich iron content ore....still is near 40 to 50 years later

I don't believe the reflector theory. The knowledge and materials were not available. It's much more likely that animal bones and fat were used as fuel for the temperatures needed. Bones gave old societies a very hot fuel source. Probably used for smelting ores. Burning bones.....a lost art.

No, probably just wood...

..."Now, archaeologists from Forest Enterprise Scotland working with Stirling University and a squad of volunteers drawn from the area have been able to determine the source of the heat following a research project at the site.

It is now believed a timber superstructure supported by the ramparts was set alight, with the fire burning down on the stones and heating them up “like an oven”, according to Matt Ritchie, archaeologist with Forestry Enterprise Scotland.

Mr Ritchie said tests had shown blocks of molten stone were formed in anaerobic conditions without oxygen and likely caused by a “tremendous heat from above”."...

https://www.scotsman.com/arts-and-culture/archaeologists-solve-ancient-mystery-melted-iron-age-fort-296899

The iron age came after the copper and bronze age,which goes back to around 3500 BC.It was a progressive technology,and they were very familiar with copper and bronze metalworking by 500 BC,which is considered to be the date of the molten stone walls.

By the time iron was smelted,the copper/bronze age was very mature.

So what materials and technology were not available?

As I stated,the discovery of focused sunlight could have been serendipitous,and was exploited.

A cylindrical paraboloid reflector is very simple to make,and it focuses to a line,not a point.Trial and error with the curvature could have been effective.

It could have also been made in sections that were independently moveable for best results.

Some DIY satellite receivers were made this way, and the LNB was moved along the length of the cylinder to change satellites.

Humans were just as intelligent then as they are now,and they didn't have as many distractions.

The Atladle was invented around 17000 years ago by the Upper Paleolithic humans in Europe.

Anyway,everyone has a theory to end all theories,but are frequently wrong after many years of misguided effort.

The burning wood theory is disputed,as I said in one of my previous posts.

This is my theory and I'm sticking to it.

I think it's more of a relic of warring factions over many hundreds of years, each burning down each others forts every other generation or so....

https://en.wikipedia.org/wiki/Hillforts_in_Scotland

As weird as this is, I agree with SE. I think it is more likely the result of demolition than construction. Torching things has alwasy been one of our favorite past times. He learned early on that heat caused stone to weaken and fracture so superheating the wall would make them brittle and useless for defense but still leave the structure useful for shelter.

"The Atladle was invented around 17000 years ago by the Upper Paleolithic humans in Europe."
The Atladle was rather old hat at only 17,000 years ago and onviously a patent/copyright infringement - maybe we should take the Europeans to court and get some cash
The Australian Aboriginals as much as 40~50,000 years ago were using a woomera.
The Mungo Man remains from at least 43,000 years ago show severe osteoarthritis in the right elbow associated with the use of a woomera.
Lawrence, Helen (2006). Mungo over millennia : the Willandra landscape and its people. Sorell, Tas: Maygog Publishing. p. 42. ISBN 0-9758199-1-7.

How it was done is one thing but the why may be ;

Theory # 1

Waring tribes would either steal or destroy the food supply of their enemy so the burnt grain stores is possibly the cause and the melted stone an unintended byproduct.

Theory # 2

It may have been done deliberately for sterilisation and sealing the walls against moisture ingress for storing grain , as moisture and mould is detrimental to grain storage.

They didnt melt the gold , they just used the fire to make the quartz brittle so it could easily crush in the stamper mills.

There are hundreds of chimneys still found in the old gold fields to this day , the height of the chimney may indicate convection was used to increase airflow through the base of the fire.

So the slag heap beside the chimney was not really molten rock from the process only from the Szechuan Beef sauce being emptied out, I sit corrected!

"I am sorry but I don't see bronze age warriors having the ability or time to fashion a parabolic reflector accurately enough to get a concentrated beam, "

You don't need to make a parabolic mirror: you tell a hundred soldiers to each make and polish his best flat one square metre (four square cubits, whatever) mirror. Then you label the wall in 2 foot square sections starting in the middle at the bottom and moving out radially. You arrange the men on ramparts about twenty yards away as if you were about to take a school photo, and tell them all to shine their "light" on 1 etc.

Yes, the brass mirrors can be flat. As this refutation demonstration with the Mythbusters team shows. Unlike the original Mythbuster attempt, the mirrors rested on a wooden jig instead of each individual unsteadily holding a mirror reflection on a common point. After 40 minutes a glowing ember formed. In 2 hours of sustained focused and tracked light the black pitch coated ship hull did burst into flames under the 37.7°N latitude San Francisco sun.

Scotland lies farther north at 55°N and higher. Summer will certainly be longer in Scotland than San Francisco but I wonder about the amount of sunlight available to continue melting a part of a wall.

A bonfire banked against the rock wall to destroy the wooden structures of the fort or to just continue to clear out unwanted timber seems so much more likely than a rig of brass mirrors waiting for the clouds to clear.

...just a curious comment from me.....I fanned a small piece of stone with an oxy/acetylene torch ... but apart from glowing bright red... nothing happened ... it certainly didn't melt.

...so what sort of heat is required ... or did i pick the 'wrong' stone to try

The stones used for brick making to line blast-furnaces don't seem to melt....

In Utah several decades ago an inventor covered the interior of a 60 ft diameter parabolic antenna with mirrors to concentrate solar heat onto a flow of raw mineral ore. The idea was to vaporize the flow and then as the various minerals would cool and solidify, each at their own temperature, there would be a dropout and collection area for each thusly separating out the gold, silver, quartz, etc.

The test day came, the powdered ore was flowing, the sun was hot, but just a bit of wind... Just enough to swing the antenna around sending the focused beam into his house.

His wife, meanwhile cooking in the kitchen, dropped a fork and bent over to pick it up... Just as the beam came through, taking out the kitchen windows and wall, going through the house and blasting a hole in the living room wall as well. No injuries, but the tests were definitely delayed!

Reference? I find that story impossible to believe, for a number of reasons:

1. A 60 ft diameter parabolic reflector (which is NOT an antenna), is not likely to be strong enough to support much more of a "mirror" than aluminum foil.

2. A parabolic mirror can only focus the incoming energy properly if it is aimed directly at the energy source, in this case the sun. If the wind blew the mirror to point in a different direction, it would ruin the focus. It is extremely unlikely that the house would be anywhere near to a position where a slight movement of the reflector would aim the focus at the house, and if it did, then the house itself would block off much of the light reaching the mirror.

3. Parabolic mirrors have a very definite focal length. The likelihood of the house being at that focal distance is essentially zero.

4. Parabolic mirrors have a very small depth of field. If all the above conditions were met such that it blew out a kitchen window, there is absolutely no chance of it doing significant damage to another room.

5. In order to achieve the high temperatures required, the focus area must be very small; certainly not large enough to take out multiple windows and a wall, even if it were to somehow sweep across the area.

Hi, reference = me. I haven’t followed up on the project but was there in person, the day AFTER the mentioned happening. Heard the stories and had a good climb around tour of the apparatus and saw the damage to the kitchen wall. Whether this thing ever worked for separating out elements in ore, or not, I don’t know, but it was certainly imaginative and intriguing, although scary.

1. I may have exaggerated the size of the former ANTENNA which could have been 40 ft diameter. It was purchased via a surplus government / ex-military equipment facility. It was substantial in construction and supported the mirrors well.

2. What you say about focusing is true, but it was being set-up when the wind moved it into an unexpected, and undesired, moment of alignment with the sun.

3. True, about focal lengths, but there were added reflective surfaces to position the energy.

4. I only have seen the kitchen damage. Did not enter the house. The story was told by the inventor and his father who was there when it happened.

5. As mentioned, the project was still being set up, so the focusing system had not been set.

On the other hand, this is the same dude who had an idea of how to powder the coarse ore to prepare it for the solar vaporization system which he had in mind. He purchased a largish jet engine, bolted it down, fueled and fired it off and with many witnesses, (not me), took a shovel full of rocks and threw them into the intake. The machine was not happy! It half blew up, jumped off its mounts and rolled/tumbled down the hill side, towards town. No one injuries except perhaps his pride.

This "guy" reminds me of another improbable American inventor.

Good story!

I have a cold fusion reactor for sale - interested?