[Next] [Up] [Previous]

Temperature Scales

To the left is a scale for temperature conversions. I had been thinking of temperature at the time I made that chart because it was a bit cold where I am; so the thermometer in the chart shows a temperature of 5 degrees Fahrenheit or 15 degrees below zero Celsius. The scale converts not merely between Celsius and Fahrenheit, but also between them and Kelvin and Rankine.

The Rankine scale of temperature uses Fahrenheit degrees from absolute zero, and thus was used in formulas used in aviation in countries using English units. It is named after William John Macquorn Rankine, who did considerable work in the study of thermodynamics. He is also the author of the following poem:

When I was bound apprentice, and learned to use my hands,
Folk never talked of measures that came from foreign lands:
Now I'm a British Workman, too old to go to school;
So whether the chisel or file I hold, I'll stick to my three-foot rule.

Some talk of millimetres, and some of kilogrammes,
And some of decilitres, to measure beer and drams;
But I'm a British Workman, too old to go to school,
So by pounds I'll eat, and by quarts I'll drink, and I'll work by my three-foot rule.

A party of astronomers went measuring the earth,
And forty million metres they took to be its girth;
Five hundred million inches, though, go through from pole to pole;
So let's stick to inches, feet and yards, and the good old three-foot rule.

While the pre-eminent utility of the metric system in carrying out calculations of every sort is inarguable - a trifling example might be to figure out how many times a book might be laid end to end on the road between two cities, when the book is measured in inches, and the road in miles, as against when the book is measured in centimetres and the road in kilometres - the discomfiture, inconvenience, and expense of converting the measurements used in daily life can be deplored as unnecessary, and, since it was unpopular at the time, as high-handed and thus inconsistent with the meekness, humility, and obedience which a democratic government should manifest towards its populace as a general rule, if not at all times.

Of course, just as it is popular in each instance to spend government money, and unpopular in each instance to levy taxes, but steering the country into debt is unwise, so there are cases in which a thing unpopular at the moment must be done for the sake of the long term well-being of the nation, and it would seem that the adoption of the metric system, even if it could have been done more gently in some instances, was one of those cases. Still, it is touching that Rankine, himself a scientist, spoke up not for his own self-interest or even that of his fellow scientists, but instead that of the common British workman.

And, as it happens, the polar diameter of the Earth, in inches, is indeed some 500,531,700 inches, but that would require making the inch longer by about one-tenth of one percent to make it a geophysically-based unit.

Also included in this version of the chart is the Réaumur temperature scale, in which zero is the freezing point of water, and 80 is the boiling point of water. It is likely in contrast to this scale that the Celsius scale was also called the Centigrade scale. As well, the De Lisle temperature scale, which starts at the boiling point of water as zero degrees, and works downwards to the freezing point of water at 150 degrees (as revised by Weitbrecht), is shown. So is the temperature scale of Olaus Roemer, who first obtained an accurate estimate of the speed of light by observing the motions of the moons of Jupiter; this scale had the same zero point as later used in the Fahrenheit scale, which it inspired, and its other calibration point was 22.5 degrees, normal human body temperature. In the chart, this is aligned with 37 degrees Celsius, or 98.6 degrees Fahrenheit, the modern accepted medical value for normal human body temperature. This may be anachronistic; measurements at the time of skin temperature tended to yield a value of about 96 degrees Fahrenheit. Not depicted on the chart is Newton's temperature scale, in which 0 is freezing, and 12 degrees is body temperature. Many other temperature scales existed, numerous cities, such as Florence and Edinburgh, having, for a time, their own temperature scales.

When Anders Celsius first proposed his scale, it worked downwards as did the De Lisle scale, 0 as boiling, 100 as freezing. Both he and Carl Linnaeus later revised the scale to its present form. Just as Celsius was formerly known as Centigrade, Kelvin was formerly known as Absolute.

Modern thermometers use alcohol instead of mercury as an indicating fluid, both because mercury freezes at 40 degrees below zero (Fahrenheit or Celsius!) and because alcohol is cheaper. Traditionally, the mercury in most thermometers (although not fever thermometers) was dyed red for better visibility. Why red, instead of perhaps blue or green? Perhaps because Roemer's thermometer used red wine as its indicating fluid, and Fahrenheit, after studying his efforts, decided to use mercury as an improvement. Of course, red is also the color of fire, and thus easy to associate with heat, and that could well be why the convention was persistent.

A scale of temperature not shown here is the scale of degrees Smurdley, which forms part of the Potrzebie system of units given in MAD magazine #33 and which was devised by a youthful Donald E. Knuth.

The account given noted that 100 degrees Smurdley was equivalent to 27 degrees Celsius, but neglected to state another point on this temperature scale.

However, it is noted that the specific gravity of Halavah is 3.1416, and that its specific heat is 0.31416, Halavah being "a form of pie".

Also, the fundamental unit of volume in this system is the ngogn, and the basic unit of weight is the blintz, which is the weight of one ngogn of Halavah. This would give it a specific gravity of 1, not 3.1416, in the Potrzebie system of units. But conversions are also given, and it is noted that one blintz is 36.42538631 grams, and one ngogn is 11.59455 cubic centimetres. If we divide 36.42538631 by 11.59455, we will obtain 3.141593965..., showing that the specific gravity of Halavah was given in the metric system, not the Potrzebie system.

We can then assume the same for the specific heat of Halavah.

The amount of heat energy required to raise the temperature of one blintz of Halavah by one degree Smurdley is one vreeble, and the table of conversion factors gives one vreeble as 34.330 calories.

Multiplying 0.31416 by 36.42538631, one blintz of Halavah is equivalent to 11.4433993631496 grams of water; heating that by 34.330 calories will raise its temperature by almost exactly 3 degrees Celsius.

Thus, rather than 0 degrees Smurdley being the same as 0 degrees Celsius, as some have assumed, 0 degrees Smurdley is the same as -273 degrees Celsius. One can presume that -273.16 degrees Celsius, the absolute zero of temperature, was intended, and thus the Smurdley scale of temperatures is an absolute scale of temperature, like the Kelvin and Rankine systems, rather than a conventionalized one like Celsius and Fahrenheit.

[Next] [Up] [Previous]