Cloud Nine is now Cloud Ten

I’ve been reading The Cloudspotter’s Guide: The Science, History and Culture of Clouds, by Gavin Pretor-Pinney. Pretor-Pinney is described on the back cover as “a former science nerd” who “has been obsessed with clouds since childhood.” He’s the founder of The Cloud Appreciation Society. Click on the link to see some great cloud photos (they make nice background photos for your computer screen) and lots of information.

The Cloudspotter’s Guide is the best kind of popular science book – fun to read, full of learning but not ponderously so, and about a really fascinating subject. I love reading about ordinary stuff I never really thought about before (the prime example of this kind of thing would be The Secret Life of Dust, an absolutely riveting book about . . . dust). It’s one of those books that, while you’re reading it, you constantly want to turn to someone and say, “Hey, listen to this. Did you know . . . . . .”

Cloud nomenclature began in the early 1800s, when a Quaker amateur meteorologist named Luke Howard proposed a classification system for clouds similar to the Linnean system in botany and zoology. In 1896 a Swedish meteorologist and an English one formed a Cloud Committee to develop an international system of cloud classification. This committee published The International Cloud Atlas. “Now published by the World Meteorological Organization, it is the undisputed authority on cloud classification, and a book that any serious cloudspotter should own,” according to Pretor-Pinney.

In the original 1896 edition, there were ten cloud genera, and Cumulonimbus clouds held the number nine spot. Cumulonimbus are thunderclouds, which can extend up to summits at 60,000 feet or more (taller than Mount Everest). So to be “on cloud nine” was to be on the very tallest cloud – up in the stratosphere.

As early as the second edition of the Cloud Atlas, though, the genera were rearranged, and Cumulonimbus was reassigned to the number ten spot. This didn’t matter to popular culture, of course. The phrase “on cloud nine” turned out to be a very sticky meme.

Sort of related: one of my favorite songs is the rather little-known “Cloudy” from Simon and Garfunkel’s Parsley, Sage, Rosemary and Thyme album.

Photo courtesy Flickruser kevindooley