Darwin’s Fulgurites

I’m fairly convinced by now that the Voyage of the Beagle is a decent cure for insomnia. I only manage a chapter at most before the eyelids start drooping. I don’t understand it, it’s actually a really interesting book with lots of stuff to take in but it invariably makes me fall asleep. One of those little mysteries of life, I expect.

I’ve already found a favourite bit. At the end of Chapter 3, Darwin mentions finding “a group of those vitrified, siliceous tubes which are formed by lightning entering loose sand”. These tubes are fulgurites and can be found all over the world – anywhere, in fact, you have sand exposed to the elements and a recent thunderstorm.

Despite being common, fulgurites are incredibly fragile and can break very easily. Many beach fulgurites can be in excess of ten or fifteen feet tall initially, but if the storm is especially fierce, they will often fall and shatter into numerous smaller pieces which wash away and surface on other beaches which may be less sandy. The fulgurites that I have are all between 1-2 inches long which I believe is about average.

Darwin gives a very detailed description of the fulgurites he found near Maldonado and this leads to an analysis of the action of the lightning on the sand. He notes that attempts to replicate this action in laboratories has proved unsuccessful, so don’t expect to be coming across artificially formed fulgurites any time soon. It’s a fascinating section and extremely thorough given that at the time Darwin was an amateur natural historian rather than a professional scientist. He comes across as being well read, learned and very objective.

On the whole, the Voyage is a fascinating insight into the mind that changed the nature of biological and geological history forever and well worth a read – if you can stay awake long enough.

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