February 23, 2013

Screw stoppers of Upper Paleolithic Dordogne

While not really a novelty, I bet that most readers have never heard of this (I had no idea myself admittedly). David Sánchez discusses this week at his (Spanish language) blog Noticias de Prehistoria - Prehistoria al Día the existence of several most intriguing conic screw pieces found in Gravettian and Magdalenian sites from Dordogne (Aquitaine, French Republic), a district that (because of its great density of findings and cultural centrality for Middle and Late UP European prehistory) I have sometimes dubbed the Paleolithic Metropolis of Europe.

Drawing of two ivory (?) stoppers from Combe-Capelle and Fourneau du Diable
(from Don's Maps, ultimately from S. Lwoff 1968)

Stopper of bone (?).
First reported as
from Laugerie-Haute
but apparently the
same as above (bottom),
from Forneau du Diable.
What are these magnificent pieces of Paleolithic craftsmanship? Apparently they are nothing else that that waterskin stoppers. Don's Maps suggest (scroll down) that the waterskin's neck hole would be made with a long bone hollow piece (just get out the marrow and tie it tightly to the skin's neck with a couple of thin ropes after performing two grooves on the external surface of the bone piece), then just apply the screw stopper forcing the bone (which is hard but somewhat flexible) to adapt to it. Naturally the inner groove would be created as you repeat the process once and again, surely having to push a little more each time (the bone tends to expand somewhat under the internal pressure).

Why are they conical and not cylindrical like modern ones? Surely because the same stopper (hard high quality work) was expected to serve many different waterskins, with different neck sizes. Also the very process of creation of the neck's perfect fit requires of an initial process of expansion for which a cylindrical stopper was not fit.

It never ceases to amaze the ingenuity and creativity of our Paleolithic ancestors, right?


Sources: Noticias de Prehistoria[es], Don's Maps.



Update (Jan 7 2014):

I just got feedback from Don Hitchcock (the author of Don's Maps and main ultimate source for this entry) saying that he found that the photographed stopper and the second drawn ones are the same (from Forneau du Diable and not Laugerie-Haute, as originally reported), complaining that the artist 'gilded the lily' more than a little with regard to the perfection of the screw thread.

I fear he must be right because some details in the handle are very similar. It is a bit disappointing but I believe that the original hypothesis about their use as stoppers stands anyhow. 


Update (Jan 10):

Don Hitchcock has updated his page on the Paleolithic tools with other two example of water bag stoppers. These don't seem to have any clear spiral design in the screw but at least one uses instead parallel groves.

To the right: ivory stopper from Laugerie Haute Est.

Below: ivory stopper from Brassempouy (Aurignacian):


14 comments:

  1. Hi Maju, via Facebook some friend show me this link

    Im not sure if stopper or pendant, I saw it when I was working in post,but finally I didn´t include because my doubtsand I think we ask to permission to take the image.




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    1. While the general design is similar it lacks the well-finished screw (instead just some marks), so I would not think it as a stopper. However the overall design is similar and the work very nice, suggesting that already in the Aurignacian the people had the cultural-technical ability to work that kind of artifacts.

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  2. A stopper with a spiral groove would leak, obviously.

    A functional stopper might have annular rings, perhaps, but even no rings at all would be preferable to what is illustrated.

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    1. Why "obviously"? Notice that the user is adapting (according to Don's Maps' theory) the bone "neck" of the waterskin dynamically as it is pressed from the inside. Another hypothesis we discussed at David's blog was using hot bee wax for the outer screw but this would be more fragile. A third hypothesis was to cover the inside of the bone "neck" with the excess of skin, which wet or dry, would also mark the screw as it was pushed in.

      All them should work probably but I'm not sure which is best: only an experiment would solve the riddle. Modern stoppers anyhow all have spiral screws but they are not conical and also take often advantage of rubber or maybe cork to further seal the hole. I have right in front of me a bottle with an spiral groove and it does not leak at all because the closure is based on pressure, the groove actually serves to enable and direct that pressure.

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    2. "Obviously", because a seal, considered geometrically, is always a closed figure, Maju. Think of a cork in a wine bottle. The shape of where the wine, cork, and glass, meet is roughly a circle. A seal will always be a closed figure like that. When it doesn't close, as is the case with a spiral groove, it will leak.

      This whole idea fails the smell test, being an overly complicated solution of very doubtful efficacy to a fairly simple problem. The simplest, and to my mind most obvious, way of closing a water skin is to fashion it with a neck, fold the neck over once or twice, and secure it with a thong or the like. If you wanted a stopper of some kind, again you might fashion the skin with a neck and use something like what's illustrated, there, but with annular rings perhaps instead of a spiral. Don't know about now, but it used to be that the stoppers used for air mattresses were made that way, tapered and with slightly raised annular rings. Pouring spouts for liquor bottles have annular rings like that for the same reason.

      "I have right in front of me a bottle with an spiral groove and it does not leak at all because the closure is based on pressure, the groove actually serves to enable and direct that pressure."

      No, you likely have a bottle with a screw top and this latest attempt at misrepresenting objective reality is duly noted.

      The threads on a screw top do not form a seal as such and, if they did, it would leak. The seal of your bottle is formed between the flat, round inside of the cap and the round lip of the bottle itself. The threads are there to hold the cap tightly against the lip. That is all.

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    3. The stopper carves its own groove either on the bone making the neck, the leather on it or the suggested wax. That means eventually a perfect fit in at least several turns of the spiral. The pressure does not leave micro-capillarity, so there is no leak.

      I know of this from my time as gardener: clay is effectively impermeable because its grains are so small that the micro-capillarity is almost nil. Instead sand, with big grains allows water to filter through easily. A gardener or farmer generally wants certain intermediate texture so the water can flow but does not drain too fast. Very small interstices may still allow air to circulate but not water or other liquids.

      This is a bit different but the essence should be the same: you just do not allow enough space for the water to flow and you achieve that via pressure. Rubber joints or corks work on the same principle in fact, regardless of shape. You surely imagine that along the spiral there is a hole large enough to allow the leak but nope: there is no hole and therefore no leak.

      "The simplest, and to my mind most obvious, way of closing a water skin is to fashion it with a neck, fold the neck over once or twice, and secure it with a thong or the like".

      Looks a nice method and it may well work as well, but the stoppers depicted here are a conceptual or technological advance beyond it. Even chimps solve problems just for the fun of it, humans even more and someone in the Paleolithic seems to have found an improved solution to your thong idea.

      "No, you likely have a bottle with a screw top"...

      Not your usual screw top at least. I have a bottle with a simple circular metallic top with four flanges or "teeth" to the inside. The bottle neck's exterior has four partial spiral grooves: the top's flanges follow the spirals and with a mere 30º-45º turn the bottle is closed or open. When I turn it upside down (and is closed) nothing falls at all. The closest I could find on a search is this image but the inside of the top is not apparent (however it may remind you of something familiar). The only flexible part is a thin rubber band along the inner edge of the top (otherwise metal, the bottle is made of glass), in the Paleolithic case that flexibility would be provided by the leather or the neck's bone itself.

      Your lack of trust is amazing anyhow. Mind you that it talks only of your character because I'm not intently misrepresenting anything.

      "The threads are there to hold the cap tightly against the lip".

      Maybe but it all works by pressure in any case and has nothing to do with the shape of the stopper.

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  3. "The stopper carves its own groove either on the bone making the neck..."

    I will not waste time on your fantasies, Maju. It is enough to state for the record that you are full of shit and move on. Of course it would leak and you obviously don't even understand what is under discussion.

    The bog-standard, screw top that you describe functions precisely as I said it did. The fact that this is utterly beyond your comprehension would be laughable, were it not so maddeningly typical of your pseudo-scientific story telling.

    I have reached a point where I don't trust anything that you write, not on any subject. I have caught you distorting the truth too many times. I have for too long watched you hold others to one standard of evidence -- and behavior -- and yourself to quite another. To my eye, you lack the emotional maturity to accept that you might be wrong about anything, even something as trivial as a screw-top bottle. It poisons everything you do and renders your every claim deeply suspect. And the way that you insult and deride anyone that dares question you tells me all I need to know about your "character".

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    1. So you are right and nearly everyone else (Don's Maps author, whose idea is), David, me and the many other indidviduals, including some qualified prehistorians (David himself but also people he asked at faculty or by email), who think that the stopper theory is perfectly valid are wrong.

      And therefore you use this opportunity to insult me in two paragraphs out of three. You get a warning, indeed. You have all the right to disagree, make criticisms, etc. but you are as of late too often throwing personal attacks. And that is simply not desirable nor acceptable.

      "... you insult and deride anyone that dares question you"...

      I do not think I do. I have got a spiral of tension with Terry that is getting vicious as of late - but I'm not necessarily (nor surely in most cases) the one insulting first, just that I also have a character and if I am insulted I will eventually strike back, after all this is MY blog, just like my living room, and I demand a modicum of respect for myself (and everyone else) anywhere but very especially at MY home. You are very welcome if you come in good style and agree to disagree and all that but you are as of late making many personal attacks, so the least I can say is that I don't like that at all: please correct your attitude. If you wish to slander me elsewhere, I will probably not even know, so I won't care. But if you come to my place and start questioning my integrity, then I eventually get angry, logically, and either strike back or take measures of both.

      I have of course an alternative that many bloggers have chosen: to moderate comments all the time, so for example this insulting one of you would have never made it through and you would have surely entered a black list. But for various reasons I prefer not to pre-moderate comments. I hope that also says something about my character, which, for good and bad (both), is quite frank and direct and about my like of fresh live discussion, with the only limit of respect.

      Respect for the blog, respect for me, respect for other readers and commenters, respect for the ideas they may have, even if wrong.

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  4. "I have got a spiral of tension with Terry that is getting vicious as of late"

    I must say I thought your last comment at the genetics of East Asian hair was very measured. I hope the attitude you managed to express there is transfered to the debate here.

    "but I'm not necessarily (nor surely in most cases) the one insulting first'

    Maju, I would certainly not ever have insulted you unless you had insulted me. Just for the record I think Va_Highlander is correct when he says:

    "The simplest, and to my mind most obvious, way of closing a water skin is to fashion it with a neck, fold the neck over once or twice, and secure it with a thong or the like".

    I have no idea what the conic screw pieces may have been used for.

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    1. If you only stopped beating dead horses and searching for burning nails, and very especially stopped overquoting to answer with one-liners of your opinion (I believe this, I think that, whatever is ridiculous/stupid/idiotic...) and instead you wrote in consistent manner explaining your viewpoint and accepting that others, particularly I, do not have to accept your ideas, then we'd be in better relation, I guess.

      You may want to take example from this recent discussion, in which neither you nor Highlander have been involved, in which we all began with different opinions but there has been a very productive, frank and interesting exchange in which all we have learned something, no doubt. We may still not agree in a lot but the way the discussion went has been most interesting. I wish all debates were like that one, really.

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  5. A coat rack? Anyway, thank you David Sanchez for the story. I have always believed our ancestors were a little more capable than we assume. The fact that we don't know for sure what this tool did supports this view. So it's great to read about their technical skills.

    May I also ask for a little civility here? I am an amateur, having studied literature and law but never archaeology. But it's good to have a forum to ask questions and offer ideas. There are plenty of blogs where intimidation and insults are common. Maju always welcomes comments even when he disagrees with them. That is what this medium should provide, in my humble opinion. Squelching discussion is inimical with the values of free speech and inquiry. Thanks.

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  6. I must say that i had several discussions in different spanish blogs with Maju and never had any problem with him; the discussions was always in the way to brainstorming and mutual knowledge.

    In my point of view we have to open mind with the paleolithic people; i sincerely believe that paleolithic people, like Clay told us, were a little more capable than we assume.

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  7. Important update: Don Hitchcock contacted me to mention that he has found that the photographed stopper and the second drawn one are the same and that the artist of this one exaggerated the perfection of the screw thread, it seems.

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