Rheaumer Scale
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At the world's only thermometer museum in Onset, Massachusetts, curator Richard Porter has gathered almost 3000 different Thermometers. He has every imaginable shape, design -- and scale. And that's not just Fahrenheit and Celsius, there's one that's, well... less well known.

Richard: "The ah, oldest one in my collection, ah, is this one here. It's an old French woodcut. And ah, I date it to the 1830s. And oddly enough it has a double scale on it. And you would expect perhaps Centigrade, but it isn't a C, it's an F for Fahrenheit. But the other scale on it, as a double scale is the Rheaumur scale. And Mr. Rheaumur invented that scale in 1730. And it's still used in parts of France even today."

On the Rheaumur scale, freezing is at 0 degrees, and the boiling point is at 80 as opposed to 100 Celsius, or 212 Fahrenheit. The gradation of temperature scales is arbitrary and Rheaumur was an arbitrary scientist. Aside from his temperature scale, he invented the egg incubator. But, it's Rheaumur's temperature scale that remains noticed, if just barely. It's unlikely to come across a Rheaumur scale thermometer in this country but if your passion, like Richard Porter's, is collecting thermometers, you'd be thrilled to find one at any price.

Richard: "I got that at the Wellfleet Flea Market for $6.00. And it, it's priceless actually as far as I'm concerned."

The Thermometer Museum is in Onset, Massachusetts. Funding for The Weather Notebook is provided by Subaru, the beauty of all wheel drive and by the National Science Foundation.