Nuts and Bolts: System Not-So-International.

The SI in the SI system of measurement stands for Système International. It's obviously a good thing to use an international system in our multi-national world, and the fact that on the whole the SI system is fitted together on a scientific basis makes measuring things as straightforward as it can be.

Now, if there's one place were you need a proper international system it is, of course, on aeroplanes, which can waft from one country to another in a matter of minutes. And so what system do aeroplanes use?

Well, vertical distance is measured in feet, speed in knots, visibility in metres, distance in miles, time in minutes, direction in degrees, and fuel in litres.

(A knot, by the way, is a nautical mile per hour, equal to (about) 1.15078 miles per hour or 0.514 metres per second.)

Ah well. 

At least everyone speaks English...

Well, more or less, anyway.

Nuts and Bolts: systems. The word system comes from the Greek syn-, which means together, and histanai, which means to cause to stand.