Possibly of interest for camping. Assuming that one needs a way to cool
something down, like a couple bottle of wine, doesn't have an ice chest
or refrigerator, but does have two terra-cotta flower pots, some sand,
some water, and a towel. A fairly unlikely scenario, sure, but hey!
Amaze your friends!

<http://lifehacker.com/5825676/create-an-electricity+free-refrigerator-with-some-flower-pots-and-sand>

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RJS