Part 16 — The Paris Thermometer

When we were in Paris this spring our friend M showed us a new kind of thermometer that tells the temperature of things by the frequency-mix of light they give off. Actually this is an old invention but the new one is very user-friendly and nicely designed. It looks like a flowerpot with an eyeball on a long stem growing out of it.

You open your mouth and put the eyeball up to your mouth and it sees what invisible colors of infrared glow are coming out of your mouth and a voice speaking from the flowerpot might say "219 degrees." That is mouth temperature on the new scale. Or it might say "2.19 grade." One grade of temperature, on the new scale, is a giant step of a hundred degrees.

Any thermal glow has a keynote frequency. (In the language of Freshman Physics, the word for this frequency is, "kayTee-over-haitch-bar", but this needn't concern us.) The important thing is that the flowerpot also knows the keynote frequency of the radiant heat—indeed it tells the temperature by measuring its keynote frequency!

What this device does is look at the blend of frequencies in a thermal glow and then it will either tell you the actual frequency of the keynote or it will tell you the temperature that goes with it.

Depending on how you want the answer it will either say "2.19 grade", or, if you want to know the frequency, it will say "2.19 mmmm...quinze per minute."

The brief hum drowns out something it may be saying and then you hear "quinze" (pronounced kanz) indicating a frequency 10¹⁵ per minute. That frequency is 10¹⁰ above middle D on the piano.

I pointed the eyeball at the sun and it said "40.8 grade." Another time, when I wanted the answer a different way, it said "40.8 quinze per minute."

If you point it at light which is a pure frequency (not the blend of thermal glow at some temperature) it won't tell you a temperature in grade but it will tell you simply the frequency of the light. One time I pointed it at some green light and it said "2.0 dix-sept." All the visible colors are between 1.5 and 2.5 dix-sept on this French frequency scale.

Something wonderful was baking something in the oven. Very briefly I opened the oven door and pointed the eyeball into the oven. The voice in the flowerpot said 3.2 quinze. So that frequency is the "keynote" in the blend of infrared in a baking oven. Madame always gets the icecream at Berthillon's. For desert she had many different kinds with interesting colors. I pointed eyeball into one of the cartons of ice cream and the voice said "1.93 quinze."

The livingroom was at a comfortable temperature, ideal for conversation, and after dark we turned off the lights and pointed the device at the wall to find out what "room temperature" is on the new scale. It turned out to be 2.07 grade, and of course the keynote in the thermal glow from the walls was 2.07 quinze.

They live close to the Eiffel Tower and there is a good view of it from their balcony. At eleven o-clock we watched the tower scintillating. Their physicist granddaughter is one of those people who, like the young Danish fellow Ole Römer, has measured a Planck quantity. She was there as well. What a splendid evening!