cL predates engineering notation. AIUI, cL makes sense, as wine bottles appear in cL steps. It is a bit like cars that are 3450mm long. Who really thinks of cars in millimetres? The friendliest unit is that which will not contain trailing zeros.
On the other hand, engineering notation makes sense - except when it crashes into old logic!
Seeing the story about the discarded beer cans which were thrown away as litter when they were actually a museum exhibit
Since normal engineering notation is to express quantities in powers of one thousand, and most packaging gives volumes in ml, I wonder why the wine and beer industry settled on using cl instead.
It's a bit like car rev counters used to have the scale as "10, 20, 30, ... x 100 rpm", rather than "1, 2, 3, ... x 1000 rpm" which is much more common these days.
On 08 Oct 2024, NY wrote
I don't know the answer to that, but it's similar to the split between the architectural/building industry using millimetres, while goods sold to consumers at Homebase and such-like give the measurements in centimetres.
I mentioned this to a friend of mine who's a small-works contractor, whose response was "centimetres are evil".
it's because most people don't think in decimals. But they can think of numbers between 10 & 20.
Wikipedia reckons 1969. That makes sense to me. My school schooling ended in 1969, which was when I could finally forget foot-poundals, bushels and Angstrom units. Not to mention esus and emus - those hopelessly compromised no-mans-lands between imperial and mksa.
Did it also explain
Psychology, I suspect. You appreciate what those numbers mean. Joe Six-pack just watches the needles swing. Vroom, vroom.
But metres make more real-world sense. It is a metre from my shoulder to the tip of my other outstretched finger-tips. True, I could call it
1000mm - but I can't imagine my arm chopped into 700 slices.
Millimetres have the advantage that with most DIY things, they are small enough that they don't need to be subdivided and so you are working with integers. And yet they are large enough that you don't often need to quote more than 1000 of them.
The metric equivalent of the 4' 8.5" standard railway gauge is usually quotes as 1435 mm rather than 1.435 m, despite the normal engineering convention that quantities should always be a number in the range
1...999 x 10^N (where N is a multiple of three: 10^-6, 10^-3, 1, 10^3, 10^6).
Yes, I suppose if wine bottles were first made in 75 cl and 100 cl sizes, *before* the engineering powers-of-1000 convention was adopted, that would make sense. Even though car engine sizes and drug doses and cooking measuring jugs are usually quoted/graded in cc or ml (synonymous except to a purist) and have been for a long time. (*)
How long ago was powers-of-1000 adopted? Did it also explain rev-counters in 10 x100 rather than 1 x1000 gradations? You'd think that you would want to avoid two gauges that had similar ranges of numbers (10, 20, 30 x 100 rpm, and 10, 20, 30 mph or km/hr). But no, that's what they did until about 2000. I *think* my 1997 Peugeot 306 still had x100 notation, and certainly my 2008 Pug 308 and my wife's 2015 Honda CR-V are x1000.
(*) My parents met when they worked in hospital pharmacy in the early
60s. At that time, fluid ounces, minims and drachms (as opposed to drams) were just going out of favour and grammes and millilitres were just being introduced.
Whereas I have no problem mentally translating "2.4" (big gradation at
2, and then four smaller gradations) to 2400 (two thousand four hundred) rpm, much more readily than 24 x 100 rpm.I wonder if it was partly driven by the USA which tends to express numbers between 1000 and 9999 in hundreds rather than thousands: "thirty-seven hundred" rather than "three thousand seven hundred" as in the UK, except for numbers in the much smaller 1000-2000 range.
US distances tend to be expressed in feet rather than yards (or simple fractions or tenths of a mile) even when the numbers are large. I was once driving in Massachusetts and I saw several signs saying "road works in 10000 / 3000 / 2000 / 1000 feet". My brain went into cognitive dissonance as I tried to translate those either to yards, or else to the tenths of a mile on the car's trip meter so I could work out when I was getting close.
Yes, ultimately units have to be meaningful sizes - and preferably a single syllable - "inch" versus "centimetre".
As an aside, Thunderbird (my usenet client) seems to have done something very clever and helpful that I wasn't expecting. I wrote powers as
10 ^ 3 etc (without the spaces) and it has very nicely translated the "^ 3" into a superscript as I would write it, when it quoted my text in your reply. Nice one!
Not the answer to the question but, my wife was teaching in primary education when the UK adopted metrication. I was in engineering and happy to accept the MKS system where the metre broke down to millimetres. Apparently, the education authority opted to use centimetres, so that was taught to primary schoolchildren!
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Difficult to say. The CGS system was in common use, then the MKS system displaced it, bringing base-1000. But it happened in different places over a long period. I recall using MKS in school from 1965 and then a few years later the syllabus was switched to SI units, which were pretty much the same for most things. I definitely remember the switch from centigrade to Celsius, as sheets of upper-case Cs were distributed to stick over the cs in textbooks.
Christ on a bike. Everyone knows that CC and CL and CM are what they are and if you cant convert from meters to millimeters you certainly don't belong on UK.d-i-y and if you cant concert between imperial and metric you probably shouldn't be here either
Indeed. When I started my pharmacy course in 1965 we had to learn how to dispense prescriptions written in imperial (avoirdupois and apothecary), or metric units. Many GPs at that time had no or only little knowledge of the metric system.
This might be interesting to some:
The best unit I have ever seen (in a Physics text book, while I was at school - I finished sixth form in 1985) was related to a production process and involved an applied torque leading to a quantity produced - a ft-lb per pennyweight-fortnight.
I was educated purely in metric, but through DIY, etc. often used imperial measurements - For practical, human-scale units, I stil prefer imperial.
There was also the problem that at the time, prescriptions used Latin abbreviations such as "qs" (effectively "enough" or "as much as you need"), "bid" (twice daily), "tid" (three times daily) etc. And they were often hand-written, by busy doctors.
At least nowadays, prescriptions (AFAIK) are generally written in English, because the computerised system "knows" what the dose of a given drug is and how often patients need to take it.
I say "AFAIK" because I haven't seen a prescription for a long time: my last three GPs have each had their own on-site pharmacy so the GP sends the prescription electronically to the pharmacist without the patient seeing it.
I always thought "prn" amusing. No doubt most scripts written 50 years ago for dispensing just after midnight at Boots, Piccadilly Circus, included that instruction...
Unless it's for something unusual ("sec art"), I have a feeling that the text is pregenerated.
Even if it's off-site, the Rx is sent electronically in most cases. But I think that it would only be fitting if the electronic Rx was written using something like:
I can remember a university lecture in viscosity where the dimenional analysis resulted in length squared over time. "You could measure in in Acres per year if you wanted to."
On 08/10/2024 15:33, NY wrote: ...
My measuring jugs are marked in fluid ounces :-)
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