Heavy Shoes

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Nov. 5, 2009

The tale of some really old soles.

Gerard Depardieu isn't the only French relic that's remarkably well-preserved. This is Sandra Tsing Loh with the Loh Down on Science.

Archeologists in Lyons, France recently dug up an 800-year-old garbage dump.

Among the cheese rinds and berets? Brace yourselves, girls – some fabulous leather shoe soles.

What's so striking about this?

Leather is skin, so it's made largely of collagen. That's the same tough protein also found in human bones.

But unlike bones, leather gradually disintegrates. It rarely lasts more than a few centuries.

However, this leather was compacted in mud lacking oxygen. That means leather-eating microbes couldn't live in it, and degrade the leather.

Still – eight centuries? To learn more, nuclear scientists at the French Atomic Energy Commission tested the soles.

They used nuclear magnetic resonance, which subjects specimens to strong magnetic forces. The reaction of a specimen's atoms reveals chemical composition.

Turns out the soles' tannins, or leather-preserving compounds, were gone!

They'd been leached out, and replaced by iron oxides in the mud. That iron preserved the soles, creating the archeological treasure now known as...

Old Ironshoes. At least by some of us.

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