From the bronze age to food cans, here’s how tin changed humanity

Tin comes from the ore cassiterite.
Shutterstock/PYP

Michael Cortie, University of Technology Sydney

To mark the International Year of the Periodic Table of Chemical Elements we’re taking a look at how researchers study some of the elements in their work.

Today’s it’s tin, a chemical that has little use by itself, but mix it with other elements and it takes on a whole new life.

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Mention tin and most people would think of the typical tin can, used to preserve foods you store in your cupboards. Tin is used here to help protect the can against corrosion (although not all cans today contain tin).

But while the use of tin in canning only dates back to the early 1800s, the mixing of tin with other elements dates back many centuries.

The tin in cans helps to protect them from corrosion.
Flickr/Salvation Army USA West, CC BY

Tin – chemical symbol Sn with an atomic number 50 on the periodic table – is soft and silvery in colour, with a melting point of only 232℃. At first sight it doesn’t seem to be a promising prospect for making anything.

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Somehow, humans discovered that adding controlled amounts of tin to copper produced a splendid, golden-yellow alloy we call bronze.

I first became interested in bronze during my final year undergraduate research project in 1978. That interest continues today – I’m working with colleagues in Thailand to reverse-engineer the technologies used to make ancient Thai bronze bangles.

Early bronze

The first known tin bronzes seem to have appeared in the Caucasus region of Eurasia in about 5800 to 4600 BCE. That these very scarce early examples of tin bronze may have been accidentally made from rather rare ores that naturally contained both copper and tin simultaneously.

There is abundant evidence that by about 3000 BCE, tin bronzes were being made in the Aegean and Middle East (Turkey, Syria, Iraq, Iran) by deliberately alloying tin and copper, with the ores being obtained from separate sources.

Clearly, a series of somewhat unlikely events had to occur before this could be the norm.

An accidental melt would have to have been made from suitable minerals containing oxides of tin and copper. The resulting metal would have to be recognised to have desirable properties, such as hardness, colour and toughness, such that superior weapons or ornaments could be produced.

Craftspeople would then have had to be organised enough to be able to work out how to repeat this smelting process to create artefacts such as swords, axe heads, bowls and bangles.

This 4000-year-old bronze axe with a low tin content was found in Sweden.
Flickr/The Swedish History Museum, CC BY

Trading networks then had to be established to bring the comparatively rare tin from faraway places, such as Afghanistan or Cornwall in Britain’s southwest, to any foundry. The metallurgical craft would have to be passed on to other practitioners, probably by oral means.

The spread of bronze

The trick of deliberately adding tin to copper then spread throughout the Old World, reaching Western Europe by about 2800 BCE, Egypt by 2200 BCE, the populous North China Plain by 2200 BCE, China’s Yunnan province by about 1400 BCE, Thailand by about 1100 BCE, and southern India by 1000 BC (if not a century or two earlier).

This has led to some robust discussion among archaeometallurgists on whether the special knowledge of tin’s useful attributes spread from a single founding location in the Middle East, or whether it had been repeatedly independently developed by indigenous craftspeople.

In the case of Thailand and Cambodia, arguments have been raised for several scenarios: that the technology was independently developed, that it was brought south from China (or maybe the reverse, exported from northeast Thailand to China), or that it was imported from Bengal.

An ancient Thai bronze bangle from a site at Sa Kweo in east Thailand.
Courtesy of Dr Supitcha Supansomboon and Assoc Prof Seriwat Saminpanya, Author provided

With China, some local scholars have favoured the view for independent local discovery of tin bronze, although it the balance of evidence suggests that the knowledge was transmitted by horseriding visitors from West Asia.

African bronze

Tin was also mined in precolonial times in Southern Africa, and some bronze artefacts – such as pieces of metal sheet or ingots – have been recovered at old metalworking sites there.

The available evidence for this region suggests the technology for producing and working iron, copper and bronze appeared contemporaneously at locations in sub-Saharan Africa, beginning about 500 BCE in the north and reaching South Africa in about 300 CE.

How did the metallurgical knowledge get to Southern Africa? Was it an indigenous discovery of the Bantu of East Africa that was then carried with them on their migrations, or was the skill transmitted southwards from the Middle East, and if so by who and how?

As in the case of Asia, interpretation of these issues can be coloured by modern political sensibilities. The question of the source of the metalworking skills that produced the beautiful copper and gold ornaments of the ancient city of Mapungubwe in South Africa, for example, has still not been settled.

Bronze in the Americas

The ancient cultures of the Americas also developed sophisticated skills for processing precious metals, copper and tin.

They were able to manufacture bronze artefacts such as rings, pendants, body ornaments, ornamental tweezers, sheet metal breastplates, large discs, ornamental shields and especially bells, by casting, albeit only from about 1000 CE in South America and then soon afterwards in western Mexico.

In the case of Mesoamerica, the knowledge of bronze was believed to have been carried north from Peru and Ecuador to Mexico by maritime traders.

Clearly, the ancient world, both Old and New, was well connected by lengthy trade routes along which ideas (and in many cases tin) flowed.

The mix of tin

The transmission of the technology can also be followed by paying attention to specific aspects of the physical metallurgy involved.

When more than about 15% tin by mass is added to the copper, the resulting alloy becomes rather brittle in its cast form, even if it still has a wonderfully warm golden yellow colour.

Somebody, somewhere, made the remarkable discovery that if such a casting is rapidly quenched from red heat into water (or better, brine), it becomes softer and relatively more ductile and workable.

The quenching heat treatment leaves a very characteristic needle-like microstructure (known as martensite) in the artefact that can be detected by a microscope. This tells an archaeologist that the part has been manufactured by a comparatively complex process, rather than merely cast.

The presence of martensite needles in microsections taken through high-tin bronze artefacts is a sure sign that they have been quenched into water from red heat.
Michael Cortie, Author provided

When the tin content is less than about 15%, no martensite forms and nothing remarkable happens on quenching.

The result obtained when heat-treating a high-tin bronze is counterintuitive because, when iron is treated this way, it becomes hard and brittle. The trick to make the bronze tough is so specific that it is most likely this knowledge was transmitted from person to person.

Its transfer across the Old World would have required knowledgeable individuals travelling significant distance to foreign climes. The appearance of these artefacts at far-flung locations across Eurasia and Africa is another sign of ancient globalisation.

An extra element

There is one more trick that appears in the ancient bronzes, although this one might have been independently discovered at more than one location.

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Some time in the Late Bronze Age or Early Iron Age (around 500 BCE), craftspeople began to add lead to their tin bronze castings. This gives the molten metal extra fluidity, allowing it to flow into fine detail in a mould so that castings with fine details and embossed figures can be made.

As an element, lead is not as shiny or attractive as tin; it is much denser and is found in quite different ores such as galena (lead sulfide). The earliest known cast bronzes with significant controlled additions of lead appear to be from China (500 BCE to 200 CE). Once again, it was clearly a deliberate innovation, and once again it spread rapidly all over Eurasia.

Another ancient bronze from Thailand (measure is in centimetres).
Courtesy of Dr Supitcha Supansomboon and Assoc Prof Seriwat Saminpanya, Author provided

As more sites such as the ones in eastern Thailand are excavated, and as the database of alloy compositions and dates increases, it will become possible to cast more light on ancient routes of trade, migration and tech transfer.

The presence and usage of tin at these sites will act as a kind of metallurgical DNA, an indicator for ancient cultural and human exchanges.

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If you’re an academic researcher working with a particular element from the periodic table and have an interesting story to tell then why not get in touch.

Michael Cortie, Physics Discipline Leader, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bread like chaff and putrid rations: how WW1 troops obsessed over food

Heather Merle Benbow, University of Melbourne

Sing me to sleep, the bullets fall
Let me forget the war & all
Damp is my dugout, cold is my feet
Nothing but biscuits & bully to eat.

Popular soldier’s song, circa 1918, recorded in the diary of Archie A. Barwick.

‘A tinned ration consisting of sliced vegetables, chiefly turnips and carrots, and a deal of thin soup or gravy. Warmed in the tin, ‘Maconochie’ was edible; cold, it was a man-killer. By some soldiers it was regarded as a welcome change from bully-beef.‘ (Imperial War Museum.)
© IWM (EPH 4379)

Many of us will be making Anzac biscuits this Anzac Day, paying homage to an apocryphal story of soldiers in the first world war and the comfort afforded by these gifts sent from home. While the provenance of this most iconic of war food is debatable, we can learn a lot about what soldiers really ate by reading their letters and diaries. These sources reveal that food was a vital part of daily life, with emotional, cultural and practical facets.

Bully beef (brined and boiled beef in a can) and biscuits were the notoriously dull cornerstones of rations for both Australian and British soldiers in the first world war.

While the rations commonly included other items such as tea, jam, sugar, bacon, peas, beans or cheese, “B.B.B.” were symbolic of the inadequacy of the soldier’s diet.

Am living quite a terrible life! No rations or. than B.B.B. How cheerful.
Leonard V. Bartlett, Alexandria, December 1915.

The shortcomings of the rations weren’t just a lack of vitamin C and other essential nutrients. Lack of variety and taste in food took an emotional toll on the servicemen, and in the soldiers’ letters and diaries we can see a veritable obsession with food.

Ration parties, like this one from the 12th Battalion Royal Irish Rifles, had to bring rations from horse-drawn limbers at night to avoid enemy fire. Supply lines were often targeted by both sides.
Essigny, 7 February 1918. © © IWM (Q 10685)

The diary of Lieut. Bartlett, a signaller who served in Egypt and Gallipoli, pithily conveys how his emotions fluctuated depending on the food available. Thus on 9 July, 1915 he rejoices:

Salmon for Brekker, what joy, my luck is really in today.

Nine days later, while suffering from one of his regular bouts of dysentery, he declares:

Feelg. rotten all day & existed on dried biscuits & tea.

For Bartlett and others serving in the Middle East, the harsh conditions made mealtimes a trial; he declared the rations “putrid”. One history describes mealtimes in the Jordan Valley in May 1918 as unbearably hot, humid and plagued by “venomous creatures” of various kinds, these miseries exacerbated by the food:

Rations reached the lines […] in a condition which would have revolted any men but soldiers on active service. The bread was dry and unpalatable as chaff; the beef, heated and reheated in its tins, came out like so much string and oil.

An Indian cavalryman who has found two starving Christian girls in the desert leans down from his horse to give one of them half his rations. At the time the men themselves were on short rations.
© IWM (Q 24724)

Supplements to the army ration were therefore intensely welcome. One letter to Mrs Hugh Venables Vernon thanking her for her contribution to the Australian Comforts Funds describes the soldiers in receipt of her gifts as “like kiddies at a picnic”.

Comfort packages – while probably not containing actual Anzac biscuits – did distribute items redolent of home and civilian life. The “Christmas billies” for the Australian Light Horse in Sinai and Palestine in 1916 included “Christmas puddings, tins of milk, packets of chocolates and similar dainties”.

Soldiers also took advantage of opportunities to scrounge, buy or commandeer supplementary foodstuffs from local populations, including “eggs and camel whey” from a Bedouin encampment in Palestine.

Its’s worth noting that conditions behind the lines in France were very different to the Middle East. Sapper Vasco, a caricature artist and draftsman, wrote letters to his wife from “Somewhere in France” as though on a grand tour, and food featured prominently in his rhapsodic prose:

Precious One […] Ever since I landed in France life has been perfect. […] This is our country. If I’ve ever made up my mind about anything it’s to get you over here ‘Apres la guerre’. […] More violent contrasts, more delicious food, wine, exquisite country, music, more café life and true ‘bohemianism’ on a Sunday or any week day than England ever dreamt of in a lifetime. […] Sunshine as mellow as Brisbane’s shines day after day on La Belle France. […] The pastry cook shops make our pastry cakes taste like piffle. You couldn’t believe there was a war on here.

During the war giving or exchanging food – often across cultural divides – was a potent act of caring, and relationships between soldiers were cemented over food. Bartlett writes of having “a pleasant little feed” with his friend Monty, and of a visit from a fellow soldier called Merrivale, who shared cake with him.

Bartlett was involved in a lively network of exchange and barter among soldiers, and regularly visited the “Indian Camp” for “chapadies” or curry. Meanwhile in Cairo, General Rosenthal enjoyed “a sumptuous dinner of about 15 courses, all exquisitely cooked. The table was set out in faultless British style, but the foods were prepared in Egyptian style.”

Indian Army soldiers eating chapadies at a camp in New Forest, October 1914.
© IWM (Q 53367)

Even across enemy lines, intercultural culinary encounters occurred, such as during the famous 1914 “Christmas truce” when German and British soldiers entered into no-man’s land to exchange gifts of rations, cigarettes and chocolate.

Australian prisoners of war experienced particularly poignant acts of generosity from civilians as they were marched by German soldiers through occupied France. Corporal Claude Corderoy Benson describes French women attempting to smuggle bread, biscuits and sweets to the POWs, often at great personal cost:

I felt I would rather have died from starvation than see these women so ill treated, and wished the poor creatures would not try and help us.

Bensen describes the deprivation of the prisoners, which makes for harrowing reading:

…very often the German guard would offer us half a loaf of bread for a watch, and I have seen gold watches and rings go for less than a loaf of bread, anything to satisfy our hunger.

In the long and arduous campaigns of WWI, food – and the lack of it – was paramount. Major battles were fought to control supply lines, and hunger was a brutalising and dehumanising tool of war. In looking at food and its exchange, we see how the conflict produced both the best and the worst of human behaviour.

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The soldier’s diaries and letters quoted in this article are publically available through the World War One collection of the State Library of NSW.

Heather Merle Benbow, Senior lecturer in German and European Studies, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Feeding the troops: the emotional meaning of food in wartime

Heather Merle Benbow, University of Melbourne

“Can an egg save a soldier?” So asked a full-page advertisement for Sunny Queen Farms in the The Age’s Sunday Life magazine last month. A young returned serviceman, a veteran of Afghanistan, looks straight into the camera. He is pictured next to a toast “soldier” dipped in a soft-boiled egg, an image replete with childhood nostalgia for many Australians, and one that speaks strongly of mothering.

The soldier, we are told, “knows how tough returning to civilian life can be for veterans suffering Post Traumatic Stress Disorder”. We can now see that, though his white T-shirt reveals a strong physique, the soldier’s eyes are vulnerable. This is a young man in need of care and Sunny Queen Farms promises to support returned soldiers with a modest donation for each pack of its “eggs for soldiers” sold.

World War I advertising similarly drew on maternal feeling.
Clarke & Sherwell Ltd, Ministry of Food/Wikimedia Commons, CC BY

This advertisement draws not just on the power of maternal feeling, and the nostalgia around childhood food memories, but on the heightened emotional significance of food in wartime. Food is central to experiences of war, and not just for the soldiers for whom it is a daily preoccupation. On the home front, too, food gains heightened emotional, social and political meaning.

The website for Walking Wounded, the organisation supported by the Eggs for Soldiers campaign, draws heavily on ANZAC imagery, and in these centenary years, World War One looms large in the national imagination. Yet we are just beginning to understand the role played by food in the emotional battles of WWI.

The ANZAC biscuit epitomises the link between food and WWI in national remembrance, and it is yet another expression of maternal care, having reportedly been devised to withstand the long journey to the front in “comfort packages”.

In WWI food was the most potent means for mothers to convey their love to sons at the front. On their return, Australian soldiers were welcomed with a hot meal at ANZAC buffets and sometimes another kind of female affection, as this iconic photograph (below) shows.

A wounded AIF soldier receives an affectionate welcome home at the Anzac Buffet in The Domain in Sydney. As men started returning from the front, the Anzac Buffet became the place where men were welcomed home.
Australian War Memorial, Author provided

The frisson between the wounded soldier and the young woman are central to this image, but the face of the older woman at left conveys a complex mixture of maternal feelings; delight at the soldier’s return, dismay for what he has endured.

In The Secret Battle: Emotional Survival in the Great War, (2010) Michael Roper writes that British soldiers’ families were effectively “an adjunct to the army, helping to ensure that the soldier stayed clothed, well-fed and healthy”. In Germany, where the British blockade quickly led to mass hunger on the home front, coping with food scarcity for her family was a mother’s contribution to the war effort.

Food is central to ideas of national and cultural belonging, something that can be used to bolster wartime patriotism, but it also gives a pungent flavour to cultural difference. Food therefore also provides powerful imagery for propaganda, such as in a 1915 Australian newspaper report that equates German food with hatred and bloodlust:

Blood sausage. Brain Sausage. Decaying cabbage pickled in vinegar … only a few of the cheery dishes in which the German rejoices, the delicacies upon which he feeds his hatred.”

In the Central Powers countries it did not take long for hunger to take a toll on home front patriotism. Existing cultural fault lines—between major cities and rural areas, between different nations and ethnic and religious groups—were brought into stark relief.

Scholars such as Hans-Georg Hofer and Maureen Healy have argued that tensions around food supply and distribution contributed in part to the collapse of the double monarchy of Austria–Hungary.

In Germany, rumours of Jewish machinations in food distribution ran rife, and resentment emerged over immigrants from the East placing pressure on scarce resources.

When we look at experiences of wartime through the prism of food we are constantly reminded of its power to to divide us, but also to bring people together. So famously a “weapon” of WWI, food can also occupy a central role in the bridging of national, ethnic and religious divides.

Australian officers having breakfast in a shell hole in Sausage Valley, Pozieres, 1916.
Australian War Memorial

Australian soldier Leonard V. Bartlett writes in his Gallipoli diary of frequent visits to the “Indian Camp” for “a feed of curry & chapadies”. During the informal Christmas truce of 1914 German soldiers entered no-man’s land and offered chocolate to soldiers serving in the British army, an event that was made into feature film Joyeux Noel (2005).

In historian Craig Gibson’s Behind the Front (2014), a recent study of British soldiers’ encounters with French civilians, the most touching anecdotes centre upon the exchange of food: a warm cup of coffee offered to an exhausted soldier, or much-needed army rations donated to hungry children.

Historian Rachel Duffett, in her book The Stomach for Fighting (2012), describes how, along the Western Front, soldiers of the belligerent armies were cared for—often tenderly—in billets. In 1922, the German lieutenant Ernst Jünger wrote of the hospitality of one French couple with whom he shared meals and many cups of tea, during which they discussed “the difficult question […] of why men must make war”.

In the article “Fighting a Kosher War” (2011), researcher Steven Schouten describes how Jewish soldiers serving on the Eastern Front with the advancing Imperial German Army were often welcomed into Jewish homes for a kosher meal.

And when the war during which so many had died of hunger ended, Hofer’s research demonstrates, food also became a tool of peace. Food aid flowed into Austria, and one fifth of Austrian children were nourished by families abroad.

In wartime, when cultural differences are amplified, food can be a potent reminder of shared humanity and reinforce a sense of belonging. Feeding is also a powerful act of love.

Indian cavalry troopers preparing a meal Estrée Blanche, France, 1915.
British Library/Wikimedia Commons, CC BY

Scholars have recently begun to examine the significance of food in wartime as an aspect that provides a tangible emotional connection to people from earlier times. As we approach the centenary of the end of the Great War it is timely to consider how food helped to heal some of the wounds of this scarifying conflict.

Heather Merle Benbow, Senior lecturer in German and European Studies, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Article: Germany – Margot Wolk

There are some jobs you could never get paid enough for to actually do – then there are jobs you probably don’t get paid enough for, yet have little choice but still have to do them. I imagine the job that Margot Wolk had was in that category.

The link below is to an article that takes a look at Margot Wold, Adolf Hitler’s official food taster.

For more visit:
http://www.spiegel.de/international/germany/hitler-food-taster-margot-woelk-speaks-about-her-memories-a-892097.html

Article: The History of Dog Food

The link below is to an article that takes up the history of dog food.

For more visit:
http://www.neatorama.com/2013/05/20/Kibble-Me-This-The-History-of-Dog-Food/