Taking back control (of our units)

As I was perusing Physics World1 earlier this year, I revisited an article by physicist John Powell2 (author of How Music Works and Why We Love Music) in which he proposed, in view of recent triumphs of populism, replacement populist units of measurement.

Of course, in the UK we could simply reinstate feet, pounds and hours (instead of the horrid European metres, kilograms and seconds), while in the US they have never gone away.
For Powell this would be too simple. He proposes furlongs, hundredweights and fortnights, on the rather contrived grounds that horse-racing is popular (measured in furlongs), as are holidays lasting a fortnight. He glosses over the choice of the hundredweight but, of course, this would reduce fat-shaming since nearly everyone’s weight would fall into the range of 1 to 3 cwt.

Elsewhere, a unit of the firkin (90lb) has been proposed, leading to the FFF system. Following the French revolution, times based on the day were proposed: the centi-jour would have been about 14 minutes.
Various constants of nature would have to be converted: Powell points out that the acceleration due to gravity, 9.8 metres per second squared, would be 71 gigafurlongs per fortnight squared. The speed of light in vacuo would be 1.8 terafurlongs per fortnight. Buying food would be awkward in hundredweights but I think this could be sorted with the division of the hundredweight into a hundred … weights! A weight of potatoes would be a bit over a pound or half a kilo.
Powell remarks that it would be popular for pi to have an exact value of, say, 3 as this would greatly simplify calculations of circular areas and so on. This reminds me that this value is implied in the Bible: I Kings 7:23-26 refers to a circular cauldron in Solomon’s temple with a diameter of 10 cubits and a circumference of 30 cubits. Now, as any fule kno, the ratio of the circumference to the diameter of a circle is pi (3.14 approx.) while 30/10 = 3. I am shocked (SHOCKED!) to find that the Bible literalists have almost entirely disregarded the word of God in this matter (though at least one person has addressed this problem and explained it away with a lot of assumptions that would have been unnecessary if the word “approximately” had been in the vocabulary of God).3

This reminds me of the sadly apocryphal stories of attempts to legislate more convenient values for pi in, of course, the USA. In one of these, in 19th Century Iowa, a legislator suggested that pi be defined as 3 to make things easier but the suggestion was quickly quashed in committee.
A more serious proposal originated with Edwin J Goodwin, an Indianan physician and amateur mathematician. In 1894, he believed that he had solved three ancient and unsolved problems in mathematics, namely squaring the circle, doubling the cube and trisecting the angle, using only a straightedge and compasses. His belief was not affected by the proof in 1882 that squaring the circle was impossible, confirming its proverbial meaning of attempting the impossible stretching back to at least 414BCE in The Birds by Aristophanes.
Goodwin persuaded the Indiana legislature to adopt his ideas in Engrossed Bill No. 246,4 generously allowing them to use his methods in state textbooks without charge, and it sailed through committee and the lower house before attracting criticism from a passing mathematics professor, who persuaded members of the Senate not to pass the bill. Section 2 of the bill states “the ratio of the diameter and circumference [of a circle] is as five-fourths to four.” This means that pi = 4/1.25 = 3.2 exactly, which it most definitely doesn’t (it’s about 2% less).

Monthly journal of the Institute of Physics and, together with Chemistry World (ditto of the Royal Society of Chemistry), my favourite reading.
Lateral Thoughts: Hail to the new, popular, units. (April 2017, p52)





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