Great Britain: 'Alf a Liter, Luv

There have been 16 ounces (Latin undo) to the English pound (Latin pondus) ever since the Romans invaded Britain MCMXXII years ago. The yard is 36 inches long because England's Henry I (1100-1135) decreed that it should equal the distance from a man's outstretched thumb to his nose. Indeed the whole British system of weights and measures is fraught with tradition, and for that reason it is frightfully hard to work with, as generations of British schoolchildren, agonizing over gills, pecks and rods, have learned.

The Continent uses the metric system, and adult...