BASES

The base 10 number system makes calculations straightforward, whether adding, subtracting, multiplying or dividing. Young people won't remember the days before calculators. But when I was at school we used a curious contraption called a "slide rule". In my mother's day, it was pencil and paper.

Yet it is easy to forget that metric measurements are in fact a relatively new phenomenon. A decimalised measurement system was first adopted by revolutionary France in 1791, replacing the previous different systems. Over time, it spread to more and more countries, so that today, it is only really the United States that does not use the SI ("système international") units of kilogram, metre and litre.

Before that time, there were all sorts of different bases. The Babylonians used base 60, which is why we still have 60 seconds in a minute and 60 minutes in an hour. The Roman numeral system, beloved of films, television programmes and the Super Bowl, was a complicated mixture of base 5 and 10. A number of currencies (the pound, the franc, the rupee) subdivided into 20. Many countries had a unit called a mile, but they were all different.

Pockets of resistance to the power of 10 still exist. Although decimalisation of the pound took place in 1971, the U.K. still has traffic signs in miles, and pubs serve beer in pints. Danish farmers still talk of land areas called "toender", even though they were officially abolished in 1907. They are roughly half a hectare (5,000 sqm), but in fact a bit bigger (5,516.2 sqm). There are similar anomalies in most countries. And industries dominated by the U.S. still use old measurements such as a barrel of oil and a bushel of corn.

However, although base 10 appears to have swept everything else inexorably away, it is not in fact the most common base system. That accolade belongs to the humble base 2. Computer chips are a mass of small circuits and switches, in which 1 represents a switch allowing current to pass, and 0 represents the closed position. With zillions of chips in the world, base 2 wins. A good job that it is computers that have to calculate in it, not humans.

Walter Blotscher