ALTHOUGH forecasts of wind speed are usually couched in miles per hour or "forces" of the Beaufort Scale, the average meteorologist usually thinks in petto of the wind in terms of knots. And thereby hang some tales that will not tax the holiday intellect too much.
In olden days, it seems, the speed of a ship was reckoned by throwing overboard a piece of wood - a log. Fastened to it was a piece of string with knots at regular intervals, which slipped through the sailor's hand as the ship moved forward.
The operation was timed with an hour glass, and it was a simple matter to arrange the knots so that the number counted by the sailor while the hour glass ran gave the speed of the ship in nautical miles per hour - or, as it came to be known, in "knots".
Not all measurements were defined by such precision. Length, for example, tended to be laid down in terms of the personal dimensions of the highest authority in the land - the reigning monarch. Thus it was that in 1592 the English Yard was decreed to be the length of Queen Elizabeth's "ruling arm" and was divided into three feet, "each of twelve inches, neither more nor less".
For similar reasons, every European region developed its own individual idea of what a "foot" should be, depending presumably on the physical characteristics of some local personage.
Most widely used by the 18th century - and the longest afoot in Europe - was the Parts foot, which in modern units "was 32.48cm. The shortest was the Hesse foot at only 25cm, and in between were the Swiss foot, the Brunswick foot, the Hannover foot, and half a dozen others - including the English foot we use today, measuring 30.48 centimetres.
As regard capacity, the old English system was based - somewhat unhygienically - on the mouthful. Two mouthfuls made a jigger, two jiggers a handfull or an ounce, and two handfulls a jack or jackpot. Successive doublings brought the jill, the cup, the pint, the quart, the pottle and the gallon - and so on through the bushel and the coomb up to a tun.
Charles I imposed a tax on goods sold by the jack, and later reduced the size of this measure so that the tax would produce more revenue - thus, of course, reducing the size of the jill as well.
The angry populace registered its protest in the form of what is now a well known rhyme, and which has nothing to do, it seems, with the two accident prone youngsters of the narrative:
Jack and Jill went up the hill,
To fetch a pail of water,
Jack fell down and broke his crown,
And Jill came tumbling after.