Making The Milligrade

By The Metric Maven

Bulldog Edition (Extra)

I have to admit that there is only one measurement identified with the metric system that gives me pause.  It’s temperature. Most of the world uses Celsius, and seems fine with it. US detractors surround me, and with boney fingers, point out with derision how compressed the Celsius scale is when compared with Fahrenheit. I object, and defend Celsius, but my heart is not exactly in tune with my defense. Fahrenheit has almost twice the number of graduations over the same temperature interval as does Celsius. My mind wants to embrace Celsius, but pines for some undefined metric mistress of temperature, with whom it would prefer to spend its time.

About a year ago, I started trying to expose myself to mostly Celsius thermometers to see how familiar and comfortable I could become with the scale. In the Winter I find it rather informative to have zero at the freezing point of water. Most of the meteorologists in the US may not say zero degrees Celsius, but almost always describe the number of days above or below freezing. The freezing point is of course assumed to be that of water. I put a Weatherbug on my computer desktop set for Celsius only, and Mike Joy was kind enough to send me an outdoor thermometer from Australia in Celsius only. I really like the way the temperature ranges for human comfort are designated with colors. I mounted the Celsius only thermometer just outside my back door. Below is an image of this thermometer:

Australian Metric Only Thermometer - Click to Enlarge

I’ve slowly become accustomed to temperature in Celsius, and if there was a total switchover to SI, I would be comfortable in a fairly short time I suspect. I seem able to keep C and F separate in my mind. All I would have to do now is drop the F from my world.

An Engineer from the UK, with whom I had worked in the past, visited with his fiancee in December sometime back. It was with pride I pointed out the thermometer Mike had sent me, and in return I received an impish smile. My British friend informed me that his soon-to-be wife could only think in terms of Celsius in Winter and Fahrenheit in Summer. This information hit my mind with the same reaction a cat might have as a stream of water unexpectedly impacts its face. I looked at her in astonishment, with my countenance frozen and contorted. Words failed me. All I could say was: “Really?” I decided this was a very, very unusual data point, and pushed it to the back of my mind—until recently. It resurfaced when Deputy Prime Minister, Lord Howe called for the UK to finish the metrication it had started years ago, but had been halted by the Thatcher Government around 1980. I was amazed in this time of deafening silence about the metric system in the US, that any politician, anywhere would mention it. I read comments by the UK Metric Association members, and one suddenly jumped out. Because the UK made it about half-way in its metrication effort, the weather reports could be in metric or imperial. The British Tabloids, who are not noted for their calm, objective approach to the news, often report Summer temperatures in Fahrenheit and Winter temperatures in Celsius. Thankfully, the UK people explained why. The Fahrenheit temperatures sound really large and give the impression of exaggerated high heat in the Summer. Great copy! The earth’s crust is in danger of melting!  In the Winter, because 0 C starts at 32 F, Celsius exaggerates how how cold Winter temperatures are. Fimbulwinter is upon us! Ragnarök cannot be far behind! Repent!

Ray Bradbury's Celsius 451 or Milligrade 4510

This is a somewhat, benign example of what happened before worldwide adoption of the metric system. One could use multiple measurement units to fool customers (marks?) into making purchases that favor the merchant when he sells, and also when he buys. The option of a choice between two similar sets of units can easily lead to confusion. For instance, perhaps the most famous novel in the English language with temperature in its title, is Ray Bradbury’s Fahrenheit 451. This is the temperature at which paper spontaneously bursts into flame—except it doesn’t. The actual temperature from the technical literature of the time is Celsius 451. Yes, the person who decided upon the title of this book made a Celsius/Fahrenheit mix-up.

If one is old enough, they may recall when Celsius was called Centigrade. The idea was that the temperature from the freezing point (triple point) of water to the boiling point would be divided into 100 parts. Zero Centigrade is the freezing point, and 100 Centigrade is the boiling point of water. If we follow the reasoning of the metric prefixing scheme, it would imply that this scale is obtained by dividing up a temperature interval called the “grade” into 100 parts. The grade would be a normalized range from 0 to 1, which makes a lot of sense.

It has been argued many times on this blog, that the “prefix cluster around unity” is a cluster. Naughtin’s Laws explicitly eschew centi-anything, and use milli instead. After much thought, I believe that the common temperature range which should have been used instead of Celsius, would be the milligrade scale. It would be from 0 to 1000. Like the use of millimeters for Australian building construction, decimal points would never be needed. Only Engineers and scientists might ever need temperatures with a precision smaller than those given by the milligrade scale. There would be no confusing Fahrenheit and Milligrade values. When it’s 100 degrees F, then it’s 378 milligrade—take that British Tabloids! If the reference book Ray Bradbury’s publisher consulted to find the self-ignition temperature of paper had been in Milligrade, there would be no confusing a temperature of 4150 with Fahrenheit or Celsius.  My fellow Engineer Lapin has told me that much of the temperature data on the web, which is meant for professionals, has the temperature in Celsius generally given to a tenth of a degree. All we need to do is move the decimal point, invoke Naughtin’s Laws and presto, a much more usable integer temperature scale for humans exists without decimal points.

If one is a strict adherent to SI definitions, then the actual temperature standard is in Kelvin. Celsius is a derived scale.  The definition of zero Milligrade or Celsius was the triple point of water. It turns out that if you have ice, water and water vapor all present in a sealed triple point of water cell, and then wait for a while, the temperature will stabilize at a very precise value (0.01 C or 0.1 milligrade), which may then be used as a standard. It is called the triple point because you have all three states of matter: liquid, solid, and gas present, and in temperature equilibrium. Celsius is actually derived from the Kelvin scale and the two points of definition are absolute zero and the triple point of water, so the 100 degree boiling point of water is no longer part of the temperature definition.

Farhenheit in a Centegrade World -- Click to Enlarge

But imagine the plight of poor Fahrenheit, it is only derived from Kelvin by way of Celsius. When you are a Metric Maven in the United States, you know what it feels like to be Fahrenheit in a Centigrade World, but my new metric temperature mistress, milligrade, would fix that problem for temperature, and provide much needed comfort to my psyche.

5 thoughts on “Making The Milligrade

  1. This is a new way to look at it. It appears however that you caused Ray’s death

    • While cooking this week, I switched to Celsius on two of my cooking thermometers. They both read out to a tenth of a degree when set to Celsius—but not when set on Fahrenheit. Clearly they are reading out to the accuracy of “milligrade.” Three digits would definitely signal you’re not using Fahrenheit anymore, and would eliminate the decimal point. When a readout is to 1/10 in Celsius or is in milligrade, it’s still more precise than the Fahrenheit readout. If you’re a cook who desires precision, Celsius to one-tenth is better.

      The Metric Maven

  2. Dear Metric Maven,
    Did you ever stop and think how compressed Fahrenheit scale is and more room on the Celsius scale. Fahrenheit is two degrees to every Celsius more or less. When compared Fahrenheit crams 212 degrees from 32 and Celsius has 0 to 100 for the mind to think about getting a glass of water to drink. This week the temperature has been between 38 to 42 degrees Celsius. Does this make me feel cooler thinking how I would feel if it were Fahrenheit, No! Do I think the heat is exaggerated when i think about the equivalent degrees in Fahrenheit No!

  3. I switched all my thermometers to deg C about a year ago – it is not hard to change if you change all at once (the one in my car, web page weather reports, indoor/outdoor thermometers ).

    And it is easy to learn – 20C is about room temp – 20 -25 – if it is 30 it is a bit warm – 40 really hot, 10 is chilly, 0 is freezing, -10 is getting pretty cold, -20 and you need to think about frost-bite, -30 and your car might not start, -40 is the same in both scales.

    Don’t try to change only one thermometer – you need to change all of them to start thinking in degC.

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