The Early Iron Age Revival of the State, VII: Briquetage

Lye: Also known as Caustic Soda

This is your top-of-the-page reminder that this "Sacred Spring" series started with a Technical Appendix about a new glycerine recovery boiler for soapmaking plant. The salient point being that soda, lye and potash are made from wood ashes and salt, and are, along with lime, the classic basic reagents of pre-modern chemical engineering. Because traditional language hates you, "soda" and "lye" are commonly called by each other's names. (Washing) soda is sodium carbonate (mostly Na2CO3, although natron is Na2CO3-10H2O). (Baking) soda is sodium bicarbonate (NaHCO3). (Caustic) soda is NaOH. Clear as glass, I hope. 

The basic argument (get it?) is that new technologies of timber removal --that would be your iron axe-- are linked to a new agro-industrial base built up around charcoal production. This much being an established point, the realisation that charcoal production also bears on soap and glassmaking is the point being explored here. I'm not going to push on with silver refining for now, because that stuff's just too weird.

So, what about this new agro-industrial base? Well, it can serve as a weak lead-in to a quote from Niall Sharples, recently appearing in this series as the careful, thoughtful and assiduous excavator of Maiden Castle: "[The technological change from bronze to iron] coincides with, and, indeed, is connected to, a major transformation of society. The principal archaeological change at this time is the transformation from a dispersed society of individual houses, scattered across a landscape of fields, to large densely occupied permanent settlements that are contained by substantial boundaries --hillforts."

My engagement with Sharples' enticingly titled Social Relations in Later Prehistory: Wessex in the First Millennium BC" is ongoing. That's how I say, "I'm still reading it," and manage to look at myself in the mirror. As I dive deeper, I am bearing in mind a noticeable tendency for recent writers on British Iron Age prehistory to namecheck "heterarchy,"a concept I first encountered in Byers' account of Cahokia, in which the prototype American city appears as a spiritual "shopping mall" of competing offers in the fields of cosmology, cosmogony, theogony and other pompous-sounding Grecisms. (Or, as I would prefer, a North American college campus, not that it is always easy to tell one of those from a mall, these days.) If Cahokia is a model for later towns from Kaskaskia down to Prophetstown, which we have accounts in the Jesuit Relations and elsewhere, a heterarchical town would also have offered a range of tribal and linguistic identities to choose from.

Is it at all permissible to compare Maiden Castle with Cahokia? Maybe, maybe not. The walls are a bit of an issue, for one.  And is "revival of the state," too bold? (Even after distancing the argument from its origins by moving to an area where the "state" is a pristine creation and arguing by analogy back to the centre, or at least to Golasecca.) I could also ask whether this new agro-industrial base flow from the revival of the state, or leads to it, but it looks as though Sharples is going to engage with the question, and I look forward to see where he goes with that.


For now, I'm going to explore what this blog has to offer about the relationship between technological and population change, with a laser-like focus on grazing land might shed some light on. So, just to be clear, it's about turning grazing land over to industrial production of fats, hide and wool and to production for export, which frees the pastoral base from its implicit, "primitive" base of subsistence --although salt production very definitely comes back to us, there.

Evidence. Livius seems to hold by the old fashioned way of blogging online, where, if you do have a real name, it's hidden somewhere in your blog, and who has time to click around to find it? The photograph is related to ongoing research into the Late Iron Age saltmaking industry of the Seille Valley in Lorraine, although the briquetage is presumably modern, as the salt crystals don't usually last for thousands of years. 

In the introduction to his Salt in Prehistoric Europe, Very Eminent archaeologist, Andrew Harding, after a bizarre segue defending himself against someone's charges that he is a Johnny-Come-Lately to the field of salt in prehistory, identifies a renaissance, a flourishing, a revolution, as it were, i nthe rapidly developing field of salt prehistory. It's this revolution that he has presumably not swooped in on and pre-empted with a hasty monograph from Sidestone Press. (If this were a review, it would be mixed.) "Briquetage" is a now-widely recognised category of extremely crude, cheaply made, ceramic good, used for the evaporation of salt brines before the widespread adoption of metal pans. Briquetage has been recognised in Neolithic contexts from Rumania, where some might have a suspicion of Balkan tale telling as the dates get pushed ever further back, in the region of Halle in Germany from the Middle Bronze Age, from Pre-Columbian sites in Mexico,  from some sites in Britain going back, again, to the Middle Bronze Age, more specifically, about 1400BC, in rich deposits in eastern Britain, notably Exeter and the Severn Valley, as well as the Saille, in the Early Iron Age, and on an industrial scale in the Late Iron Age, just before the Roman Conquest.

Unusually, the Severn Valley finds, which are traced to the long-established salt spring works in Droitwich and a so-far unidentified site in Cheshire, are distributed around these centres at considerable distance. Most briquetage salt production sites are recognised by the enormous quantity of broken pottery, because the pots are broken open on site to extract the salt, which is then packed for transport in something lighter than pottery. Droitwich and X-Marks-The-Spot, Cheshire, salt, is distributed in the pots. Sometimes, at least. Weird.

Tom Moore envisions the "Severn-Cotswolds" area. 

It is not exactly clear just how important briquetage industries were in the Iron Age. The point is that they are archaeologically visible. Other salt production techniques include evaporation pans in coastal lagoons, which we know to have been common in the Mediterranean, although these industries are archaeologically indetectable, and on the south coast of Brittany and around the Bay of Biscay, where, could we not detect them archaeologically, they might be dismissed as socially premature. (Rather in the way that we hesitate to assign too much tin industry to Bronze Age Cornwall, because it is just too early.) Brine from salt springs can also be helped along a considerable way on the path to crystallisation by human ingenuity, and an assortment of troughs and towers are known from more recent eras. Rock crystal salt can also be mined, and was, in the Iron Age, at the unique location of Hallstat in the Salzkammergut; and it can erupt from the ground and be extracted as a surface deposit, something well-studied in the Carpathians, although unknown in the wetter Atlantic littoral. 

The high-altitude salt mines at Hallstatt are associated with a graveyard with lots of sumptuously furnished graves. It seems plausible that Iron Age miners made good money, but you can make this less obvious if you try.

Finally, salt can be produced by washing the ashes of burned halophytes. (Speaking of The Engineer articles worth following up, remember the series about the harvesting equipment on the Scottish seaweed farm?) Janice Kinory points out that no evidence of salt production from ashes is known in Iron Age Britain. Dr. Kinory impresses me with her scholarship, so I'll take that as a given, but that can't be the whole of the story.  

Dr. Kinory also investigates the question of what people did with this salt, which is apparently beneath most of the scholarship. Harding, in particular, has an egregious section in which he cites a wide range of claims about minimum daily salt intakes for health maintenance, and draws a conclusion not far short of, "It's impossible to say, because some dudes are fuddy-duddies, who are, like, 'wine, women and song!' (While their female colleagues look on, appalled), and some people are orthorexic." 

Well, okay, that's a tiny bit unfair. He does cite one extreme range source that suggests a cow might need 90g of salt a day, which, given an annual yield from the Hallstatt mines of perhaps a few tons, makes it difficult to credit the traditional assertion that Iron Age farmers must have used salt to preserve food. The point is, I'm much more impressed by Dr. Kinory's use of up-to-date medical and veterinary advice, combined with a deep dive into old cookbooks. From these, it turns out that the kind of peasant societies we imagine as dependent on salt for food preservation is a much wealthier society than one that we can imagine in the Iron Age, on the basis of much ethnographic comparison.

It is true that we have an idea in our heads of a democratic, Wealden Anglo-Saxon pig farmer, sitting at ease of a winter's eve, entertaining at his table, with a slaughtered pig hanging,  "squeak to tail," from his smoky rafters. The problem is that a dry salt cure requires a 1-to-10 ratio of salt to meat. As Kinory points out, you could buy a standard-sized, 30lb block of salt on sale in a north-of-England grocery in the 1930s, because the accepted ratio was one-block-for-one-pig. Needless to say, Iron Age salt boilers on the Essex shore weren't meeting the needs of a nation of ham-and-bacon fanciers! As for sauerkraut or dry-cured cheese, forget about it. 

The Romans made dry cheeses, but thought of them as luxury goods for long distance trade.

There are, admittedly, other ways of using salt to preserve food. Wet-curing uses less salt, but is ancillary to drying techniques, requires considerable skill, and doesn't work enormously well without tightly sealed packaging. Fresh cheeses, sweet butter, ghee, sour cream, and pemmican all preserve animal-based foods to at least a sufficient degree to get a community through the worst of winter. 

The hungry months of summer are a different matter entirely, as, of course they are; because one of the reasons that it is so hard to quantify the daily required intake of salt from animal fodder is that not only does natural salt intake from fodder vary from place to place and from season to season, but so does an animal's need for salt. Milking cattle and expectant mothers require more salt; more salt is needed in warm weather, and for working animals; and stall-fed animals need more salt, because they cannot roam in search of natural sources. Harding, in the end, has a point. It's probably pointless to work backwards from supposedly secure estimates of salt needs to reconstruct the necessary structure of the industry. But we can work from common-sense parameters to use the salt industry for insight into Iron Age society. 

An Iron Age glass bead recovered at Burrough Hill by the University of Leceistershire's Archaeology programme in 2012.

 There are two briquetage salt industries visible in the archaeological record of Iron Age Britain. The Droitwich/Cheshire industry demands attention because of the dispersal of the briquettage. Finding artefacts made at a site in a scatter around the surrounding landscape promises an understanding of mobility and landscape use, especially when it can be mapped against distributions of pottery and querns (handmills for grain), also with known locations of manufacture.

The other, which came to light in the last century because of numerous Iron Age toxic waste dump sites known as Red Hills, is in Essex, along the left bank of the Thames estuary and extending around the corner into East Anglia and perhaps into Lincolnshire. The Red Hill sites are all below the high tide line, are densely littered with briquetage, have a distinctive soil, and would not have been viable work sites in fall and winter. 

There's a Wikipedia article! By Colin Smith, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=9311717

The reason for the latter is interesting, because it reminds ignorant people like myself of the actual technical complexities of salt production. It takes a reduction of 100g of sea water by evaporation to 10g before table salt (NaCl) begins to precipitate, and after producing a little less than 3g by a further reduction to 5g, the resulting liquor, or "bittern," is so high in other ions, mainly potassium and magnesium chloride, but also iodine and other mineral salts, that the liquor must either be discarded (or turned over to post-Iron Age chemists for other industrial uses); or the crystals held in storage for years at a time while these more soluble salts are deliquesced by atmospheric humidity. In practice, Dr. Kinory thinks that it is more likely that the Red Hill workers were expert saltmakers who could spoon off the sea salt crystals, and, eventually, discarded the bitterns. The resulting contamination has long since washed away, but, at the time, the Red Hills had to be periodically abandoned. 

So: i) A local industry, making expedient pottery and burning accumulated fuel; ii) expert workers; iii) seasonality; iv) a non-obvious economic logic; v) an industrial scale of production in the late, pre-Roman Iron Age.

A context for the Essex industry? Barry Cunliffe reads the rise of the "central place" in the Iron Age. Essex salt is being produced more-or-less at the apex of a fan leading down Watling Street. 

At this point, it is as well to point out that salt springs can be as much as 20% salt by weight, in contrast to sea water's 3.5%, and be free of bitterns. Salt-spring-based industries aren't necessarily more efficient than sea salt industries, since sea salter makers often use evaporating pans for a fuel-efficient first reduction step, but there is no evidence of pans around the Red Hills. 

Also, there's mineral springs, natural carbonation --why does the real world have to be so complicated?

It might be as well to return to the social studies of the Droitwich industry, to extract what we can from it. It is first of all unlikely that there was no coastal salt extraction in the Somerset Levels. The appearance of a glass industry there in the Late Iron Age is at least a terminus point. The distribution of Droitwich and Cheshire salt in its originating briquetage points to a social value being placed on its origin place. If these two sources were special in some ways, it becomes much easier to accept that we are missing a large part of the total salt production and distribution: it is "invisible salt," as Dr. Kinory says. Tom Moore's examination of find spots of, for example Malvernian querns, found in a virtual amphitheatre of locations up to 80km away from the Malvernian hills, but in site of their summits, suggests that distribution patterns are socially relevant in a context of mobile populations. Given the seasonality of the saltmaking industries, Iron Age saltmakers, at least in the Cotswolds-Severn area, presumably lived elsewhere and supported themselves in other ways during the rest of the year, underlining mobility and dispersed and regional social relationships.

In the Cahokia case, Byers wants to reject the idea of an American city on the grounds that occupation is seasonal and functional. Strip out the eye-watering academicese, and people go to Cahokia to make stuff, enjoy parties catered by various heterarchic social entities and served in red-buff ware, and participate in a spring-renewal ceremony whose cult practice is roughly fixed, even as the ideological content is contested by the various elements of the heterarchy. The problem is that this will do for any ancient city. Any consideration of the cult practice of Rome makes the place seem pretty heterarchic, and, never mind the Iron Age, cities still empty out of locals and fill up with tourists in the summer festival season in the Silicon Age. 

Taking the incipient "agglomeration" of the Iron Age of the Cotswolds-Severns in line with this model, and one can again see groups and individuals moving in and out with the seasons. Taking Godelier's New Guinea ethnographic comparison that so intrigues Iron Age scholars as a model, and we can even see various groups breaking up, with their "sorceror" saltmaker-members, possibly women, in which case witches, gathering at the Droitwich and Cheshire streams in the spring and summer to make salt, which they will then distribute --in its briquetage, to various important places in the fall, when a rising water table dilutes the springs and the firewood gets too wet to burn.

Also, and it seems reasonable, if overly functionalist, when the need for salt peaks. 

So much for that. Now I want to look at some  orthogonal, suggestive facts that take us back to the earliest Iron Age, and the earliest stages of the Seille industry, and late flourishing of the Hallstatt mines. 

(Maps taken from Pierre-Yves Milcent, "Hallstatt Urban Experiences before the Celtic Oppida in Central and Eastern Gaul: Two Case-Studies: Bourges and Vix," eds. Manuel Fernandes-Goetz, Holger Wendling and Katja Winger (Oxford: Oxbow, 2014). 

The current state of the art sees the cities of Iron Age Europe as fundamentally different from their Central Mediterranean peers. They are not "central places" within a system of centres; but, rather, are "monopolistic," often large, and best characterised as "tribal states," rather than "city states," says John Collis. "Tribe" sounds unhelpful, and what seems more interesting to me is the striking combination of size and ephemerality. The distinction that Collis wants to make is in the service of the idea that these cities are not just imitations of the Mediterranean model which, as alien implants in Iron Age Central Europe, do not flourish. This, on the other hand, will do just fine for me. It's like arguing that American Midwestern pyramid centres set in ceremonial plazas where warriors play ritual games while elders drink frothing, caffeinated drinks and smoke tobacco in ceremonial pipes aren't inspired by the millennia-older Mesoamerican practices they so suspiciously parallel. At some point, parochialism becomes parody. (And yet, politically speaking, here we are.)

What I want, instead, to focus on is location. Currently, Iron Age studies differentiates between "trade centred" settlements, which may or may not be more normally "open agglomerations," and walled "prince's seats," fuerstensitzen. 

(You know: Like this. Man, if it's hard getting water up to Maiden Castle . . . . On the other hand, we don't see the backside, so maybe Edoras is on a spur with a stream from above?)

This is all very well, but new isotope studies of bones at the Heuneburg show that the animals eaten there came from at least 60km away. Whatever we make of the ceramic assemblages that show that the Rhone valley centres were involved in trade with the Mediterranean via Marseilles and Etruria, there are other ways, and other distances, across which trade or exchange can happen. One thing that can happen is that salt can be traded long distances; but there is more to it than that, I think.

So I return to this ambiguity, of salt, soda, lye, potash, soap, glass, all derived from the same fundamental sources. You could have knocked me over with a feather when I googled through to the source material and discovered that Godelier's New Guinea saltmaker/sorcerors were making a potassium salt! Potassium supplementation of regular table salt is necessary for rehydration treatments in warm weather, but why were they focussed on potassium to the exclusion of sodium chloride, with its much more important biological role? One begins to wonder about soapmaking, out of sight of the ethnographer, but what do I know?

Rehydration, seems to be a good place to start. Andrew Harding's ridiculous, "One scientist says cows need ten times as much salt as the other scientist, so what do you think about that, eggheads?" might not be the best sales job for the Antiquity brand, but I hope it makes more sense to think about what a specific cow or horse that's just been driven more than sixty kilometers to the Heuneberg, and stalled in the hot, late summer weather might need. Rehydration salts are sold over the counter at your local grocery store not just as Gatorade and Powerade, but as an oral diarrhea treatment. You cannot rehydrate with water if your electrolyte balance has fallen too low, and while the orthorexic scold will point out that our diets are already high in salt, etc., I can tell you that, as a frontline retail worker, people, in our modern, salt-saturated world, often present with symptoms of dehydration that are at once frightening (diarrhea, again) and difficult (crankiness tending towards irrational outbursts). Iron Age salt scholars have either been talking to each other, or reading each other, because I doubt that they have all independently come to the knowledge that the old Roman agronomic texts list numerous salt-based cures for livestock afflictions. The old Romans may be taking a "magical" view of how salt works, but there is something magical about how quickly a bottle of Gatorade can cure a serious, indeed, life-threatening complaint. "Dysentery" is no joke. (Scare quotes warranted given the extent to which simple dehydration can mimic gastrointestinal disease.) 

I can only imagine what the scene on an early Iron Age hillfort in September, when the animals are being gathered for the "ritual activities" with which Kinory associates the use of Droitwich salt in its original packaging. What, exactly, is the difference between magic, medicine and ritual? 

As the Wikipedia article notes, it took a while for the argument that the Red Hills produced salt, triumphed over the alternative argument that they were being used to make alkalis for glass production. There is a great deal of evidence for some kind of fire-based industry at the Red Hills, and before it was explained in terms of briquetage, the idea that the Red Hills workers were burning halophytic saltmarsh plants and washing their ashes, seemed highly enticing. However, if this were being done, it did not seem likely that the workers were aiming at salt production. Sodium and potassium hydroxide, widely used for salt and soapmaking, start in old-time organic chemistry at the same point as salt-making, with free sodium (and potassium) ions in water. It is not that they are more valuable than salt, necessarily, but having the raw material for the production of either at hand, the question is, which do you focus upon? I'm honestly not sure how an old time worker ensures that they get  washing soda (Na2CO3) instead of NaCl from the washing process. People just say "lixiviation," and that's that. Honestly, the more I read this stuff, the better I understand those old alchemists. If I had to sort this stuff out with the tools they had to work with, I'd go a bit nuts, too. Point is, if glass beads were being made from scratch in the British Isles during the Iron Age, as it appears they were, then there was lixiviation going on all around, even if we can't see it in the archaeological record --but probably in the last stages of the Iron Age, after about 250BC. But, as we know, glass was entering Iron Age Europe much earlier, from northern Italian industries. 

I'm probably stretching things, or succumbing to monomania, in suggesting that the archaeologically-attested long distance trade in salt underwrites a long-distance movement in livestock. It does seem absurd that there would have been a trans-Alpine trade in sheep and cattle at this early date, but the distribution of early centres does suggest trans-Alpine movement, and if it is not ceramics, or goods in ceramics, then why not livestock? Horses, and, more specifically, saddlebroken horses, are a much more prestigious good to move. If the phases of "premature" central European urbanisation are in very approximate synchronisation with the climactic phases of Mediterranean military activity: the final century of the Neo-Assyrian Empire; the rise of Carthage, with its Sicilian wars; and the Punic wars --Well, the main question for my hypothesis at this point is why I'm mixing military events in the western Mediterranean basin with events in the Middle East.