Planet Earth Online - Roman Recycling
Kat - Planet Earth podcast presenter Richard Hollingham has been asking what have the Romans ever done for us? Well, apart from building baths, sewers in cities and education, it turns out they were also into recycling. And to hear how, he met up with Sheffield University's Caroline Jackson and Harriet Foster from the Norfolk Museums and Archaeology Service...
Caroline - What we've got are six vessels. Three drinking vessels, there's two jugs and a bottle, and they're all late 4th century.
Richard - Now we've got here a modern glass which I am allowed to touch. Actually, you look at this mass-produced modern glass and you compare it with these from almost 2000 years ago, Caroline.
Caroline - That's right.
Richard - These glasses could almost be mass-produced because those three glasses, pretty much identical. You can imagine those in a box at a supermarket or something.
Caroline - Well that's right. They actually were mass-produced in a way. Glass production, certainly by the 4th century was something which was prolific. Glass is found in most archaeological contexts. It's all blown glass, this is something which came in certainly in the Roman period. The Romans invented glass blowing, something that perhaps wasn't around in earlier periods. So, to produce the glass by blowing is very rapid. It's a very easy technique once you've mastered it. So you can produce many, many vessels from a small amount of glass, and this is why these have such thin walls as well - because they're blown.
Richard - How do you know they recycled the glass?
Harriet - We've known for a long time that the Romans recycled glass. We've got evidence from a late 1st century AD source that talks about broken glass in Rome being collected up in exchange for items of small worth. There's archaeological evidence for glass recycling. So we find the equivalent of bottle banks.
Richard - So what did you do then?
Caroline - We took a lot of material from about 20 sites in Britain and analysed them chemically to see if we could see anything within their compositions which might give us an indication that recycling was taking place. And the results of that were quite surprising.
Harriet - They were surprising because of the amount of recycling that we found that was going on. A significant proportion of the assemblage that we looked at which was over 500 samples suggested to us that the glass was being recycled in quite large amounts and that was interesting because it throws out more questions about, what does that mean about the supply of glass to the province at that time? Was glass being recycled because there weren't fresh supplies available or is it something else?
Richard - Have you got any ideas why this might be going on?
Caroline - By the late 3rd and 4th century, the Roman Empire is starting to change. The large industrial complexes that you see are starting to decline, trade is starting to contract. Now, we don't know exactly what was happening with supplies of glass because we don't have any archaeological evidence at this point that is published, where we know glass was being produced. So we can't say this factory stopped and maybe that factory started, but we can say that it looks as though that supply of raw glass is starting to decline, because there is a greater proportion of recycled glass that you can see in the chemical fingerprint. We've got elements in there which can only come from mixing that can't have come from the raw materials. That's not just for the common forms and the common colours, even this more high status colourless glass, which is always thought of as something which is reserved perhaps for more specialised vessels, even that is showing evidence of large scale recycling. So it's going on throughout the glass industry.
Richard - Okay, so you're learning about the glass, but you can also, by using the glass, tell a lot about how the society was changing as well.
Caroline - Well that's archaeology. That's what we do. The glass is a really interesting material, but only interesting in what it tells us about the people who were making it and consuming it. In the same way as we look at any archaeological material, it's there for a purpose. It's there to tell us about people, the individual, and society.
Kat - That was Caroline Jackson and Harriet Foster, talking to there to Planet Earth podcast presenter Richard Hollingham. You can hear the latest edition of the Planet Earth podcast as well as links to other Planet Earth Online resources at thenakedscientists.com/planetearth.