Did you get swept up in the jubilant celebrations four years ago, in which millions of once gruesomely oppressed carpenters, map makers, printers, pub landlords, coal miners and tailors drank themselves senseless as they recalled casting off the shackles of feet, inches, miles, foolscaps, pints and hundredweights and replacing them with things whose names began with centi and kilo and mega? You didn’t? Neither did I.
In 1668, an English bishop, John Wilkins (1614-1672), published a book with a plan for a ‘universal measure’. You might think that a logically organised system of weights and measures would be so appealing to the man on the Clapham omnibus that all who heard of the metric system would immediately hurl their Imperial tape measures and scales and beer glasses into the nearest deep water harbour as they liberated the depths in fathoms by painting them over with metres. Not a bit of it. Mr Wilkins’s suggestion was more or less ignored until the mad French dictator Napoleon imposed the metric system on traders in his country by force, sending a special metric police force into the marketplaces to smash any eighteenth century French pounds and ounces they came across and then beat the trader using them to a pulp, just to show him who was boss.
Anyone who wants to learn just how barmy Napoleon’s metric system really was needs only to take a look at the French decimal time and decimal calendar, forced onto the French public in 1793. Decimal time lasted all of eighteen Gregorian months before being ignominiously abolished, while the decimal calendar was kept going until XIV, or 1805 as everyone else called it.
In a curious echo of the way Napoleon dealt with market traders who shunned his new-fangled measurements (see picture, below), British Consumer Protection jobsworths suppressed dissent by prosecuting Mr Steve Thoburn in 2001 for daring to sell a pound of bananas to a customer who asked for a pound of bananas, contrary to the Weights and Measures Act 1985, and so petty were they that they confiscated his Imperial scales.
Why should the metric system have aroused indifference on such a massive scale despite, allegedly, being a spectacularly good idea? Everywhere you look in the metric system, ten of something makes one of something else. Isn’t that idea simple and elegant enough to guarantee the metric system fame, fortune and a place in every grocer’s shop in all the length and breadth of Bonny Scotland for the rest of eternity?
Well, no, it isn’t.
It is true that throughout the metric system, the answer to any question about how many of these makes one of those is always ‘Ten.’ In the Imperial system the answer could be eight, twelve, thirty six, eighty, one hundred and forty four or even five thousand, two hundred and eighty. But although this ubiquity of tens may be an attractive feature of the metric system, it isn’t actually a useful one. In other words, if the answer’s ten, you are asking the wrong question.
Obviously, if a collection of weights and measures created for a myriad different purposes over a period of more than a thousand years and related to each other by so many different ratios that schoolchildren used to have tables of the best known ones printed on the back covers of their exercise books, it never mattered much to anyone that the ratios appeared to be as random as lottery numbers. If the apparent randomness had been a problem, the Imperial units would have been rationalised centuries ago.
Ask not how many of these make one of those. Ask instead, ‘What weighs one kilogram?’
The only thing I can think of, apart from a certain piece of platinum which is slowly wearing out in a museum in Paris, is a pack of sugar, and I guess that is because before they metricated it, sugar was packed in 2 lb bags. Even the abbreviation lb for pound is a nod to the antiquity and lineage of the Imperial unit: it comes from Latin. The pound itself was first defined in around 1300, and so was the yard, while the pint and the gallon have a confused history, started life in antiquity and were standardised in 1824. (Well, that’s really only true for small values of standardised. The United States pint is sixteen fluid ounces; the British pint is twenty.)
But ask the same question of Imperial measures and you can't throw a stone (a unit which, incidentally, originated in Roman times) without hitting an answer.
What weighs one pound? A pound of meat is enough to feed your family. What has a volume of one pint? A pint is the amount of beer you want to drink. What has an area of one acre? An acre is the area that you can plough in a day with two oxen. What weighs one hundredweight? Anything in a sack, because a hundredweight is the weight that a man can lift.
That is the conceit that keeps Napoleon's metric system going: that all lengths, all weights, all volumes can be measured by what are, when you look closely enough, three basic units, and one size of each of them fits all.
One of the unsung glories of the Imperial System was that every trade used units of measurement which it found appropriate. Tailors, for one example, measured their customers in feet and inches but cut their cloth in ells, which were handier than feet and inches for the purpose of cutting clothes. Farriers measured horses in hands and racecourses in furlongs, both of which turn out to be easier to use for their purposes than feet and inches, let alone metres. Surveyors and railwaymen measured lengths of track in miles and chains, perhaps because feet and inches gave a spurious appearance of immense accuracy. Ships’ crew navigated in nautical miles and knots rather than in ordinary miles and miles per hour, because of the relationship between the nautical mile, the radius of the earth, the degree of latitude or longitude and the angle between the sun and the horizon. Over and above all these many specialised units, the remarkable British currency of pounds, shillings and pence also served all trades. The currency even felt more like money than decimal currency does. Sums of pounds, shillings and pence clinked and weighed heavy and had dates on the coins that went back to the early nineteenth century. Pounds, shillings and pence could be divided by two, three, four, five, six, eight, ten and twelve, as well as seven if you converted the sum into guineas. The same people who struggle to divide a decimalised pound by eight knew without thinking that there were eight half crowns in a pound. That’s the thing that advocates of metric have not realised, or have realised but won’t admit. Everyone could do it. There is, therefore, no advantage at all in every measurement being ten of another one.
At least, we who lived with it could do it. Even if they wore a bowler hat, carried a furled umbrella on a sunny day and suppressed the urge to goose-step along the main road, hold one arm horizontally and cry, Sieg Heil, German spies were usually rumbled when a newsagent realised they did not know how many half crowns there were in a pound.
A thousand years of evolution had created a system of measurements and currency that anyone could use and met all the needs of trade and industry after just half an hour’s daily instruction for seven years at junior school.
Of course, Wilson was right. Different countries use different ‘customary measurements,’ but so little use has been made of the metric system that it has not split up into dialects. Therefore, metric is ideal for international trade. Everybody agrees on what a tonne of steel or a metre of fabric is.
Secondly, metric is good for scientific measurements. It is easier to coin new units using metric measurements as a basis, and easier to calculate ratios if all the measurements involved are based on the same units. This doesn’t always work. For instance, there are two units for the energy content of food, kilocalories and kilojoules, and there are several units for very long distances including parsecs, light years and Astronomical Units.
And that's it. The metric system is no use for anything else, and there's no point in pretending that it is. No wonder you hear a sort of rumble of thunder in your head any time a BBC journalist reports that he is standing half a kílometre from the front line (invariably with the stress on the i) or a patient in hospital is fifty kilograms overweight. Nobody in Britain ever uses metric measurements in such contexts, unless they have a gun held to their head. May we never start.