The Measure of All Things
From NSAI’s Archives and written by Oliver Power,Technical Manager/Electrical at NSAI’s National Metrology Laboratory
It’s a hard life working in metrology! Whenever you tell someone that you are a metrologist, they immediately complain about the weather or ask you what the Met Éireann’s Weather Forecasters are like, off-screen!
And yet, metrology is a very ancient pursuit. All the great early civilisations had well developed systems of weights and measures. Given its long history, it’s hardly surprising that elements of metrology have seeped into our culture. You might be surprised to hear that one of the very first things you learned in the playground derives from metrology:
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
There are three units of measurement referred to in this nursery rhyme, the jack, the jill (or gill) and the pail. The rhyme was written as doggerel verse during the reign of Charles I of England, who was, at that time, apparently, fooling around with the size of the measures used for beer and spirits in order to increase tax revenue.
Of course, it all ended badly when he lost his head, or “broke his crown” as the poem goes. The gill was in use for measuring spirits up to recently. And the “jack” or “jackpot”, referred to in the rhyme, may live on in the phrase “winning the jackpot”.
Nowadays we use the scientifically based SI units, but there is a nostalgic attachment to the older human-based units. The inch, foot, pound and pint are only very slowly giving way to the metre, kilogram and litre.
We still like to talk of horses entering the final furlong in a race, or the combined weight of a rugby scrum exceeding 130 stone.
Going back even further, in pre-Norman Ireland, the Brehon Laws laid down a system of weights and measures.
The natives of that time were a litigious bunch and many of the units referred to legal matters. The extent of land in the vicinity of a dwelling house could be measured by the faiche, which was the distance a man could throw a spear from the roof of the house. This ingenious approach combined the definition of the unit with a practical means of ensuring that it was respected. Errors could be fatal!
Long distances were measured in senchus mór which was the distance at which a certain type of handbell could be heard. This was often used to enforce “exclusion orders” of the time.
Another very old unit is the barleycorn, which is the length of a “standard” grain of barley. This may be of little interest to you, apart from the fact that you certainly own at least two items that are measured in barleycorns. This ancient unit has survived in the measurement of shoe sizes. So-called UK sizes start at size 1 for adults, which measures 7 7/8 inches (two hands’ breath). Sizes increase thereafter in intervals of one barleycorn.
Continental sizes are based on a system of measures called Paris points. To work out your size in Paris points, you have to measure the length of your foot in centimetres and divide the measurement by two-thirds. Confused? Then don’t even think about how hat sizes are measured!
So, as you can see, metrology is not all about lasers and atomic clocks. We encounter it everyday, even if we don’t always recognise it!
To find out more about the work of the National Metrology Laboratory, visit https://www.nsai.ie/national-metrology/
[Disclaimer: All reasonable effort was made to ensure that the information on this page was correct at the time of publication. Any views or opinions expressed on this page are not necessarily those of NSAI. NSAI accepts no responsibility or liability howsoever arising from the contents of this publication or any errors, inaccuracies, or omissions in the contents of the information provided therein.]
