I remember the introduction of the pascal (vs newton per meter squared) for pressure, siemens to replace the “mho” (reciprocal ohm) and picofarads to replace micromicrofarads.

Fortunately, my first employer was dual and wanted to go metric; I served on the metrication committee. My second employer was metric. So my inability to engineer in Customary was never a real problem. Since this was very much pre-Internet, it was hard to find simple answers about Customary, like “how big is a gallon.” Sources would inter-relate pints, quarts, gallons, etc, but it was VERY hard to find a US gallon was 231 in³.

As we insisted our supply base be metric to, I never really encountered engineers who worked in Customary, although I was aware they existed. In my final assignment, I was head of technical planning and interfaced with universities, national labs, NASA, etc. I was VERY surprised at both national labs and NASA to find engineers who thought in Customary and only converted to metric because their bosses made them. At first I thought they believed we used Customary. I made clear that we didn’t, and we proceeded to have translation difficulties that precluded fruitful discussion. Although he was writing about something quite different, it reminded me of C. P. Snow’s “The Two Cultures,” two groups who couldn’t talk to each other.

On the other hand, as the US is considerably less metric than the UK, I had to learn enough Customary to “survive” in my personal life. Needing to know two systems can only be a nuisance and waste of time.

Book 1

First edition, published in 1953

“Electrical theory has been burdened with several systems of units. In 1901, it was suggested by Prof. Giorgi, an Italian scientist, that the confusion caused by these different systems could be eliminated by the adoption of the metre, the kilogramme and the second as the units of length, mass and time respectively and the adoption of one of the practical units, such as the ampere, as a fourth fundamental unit. This metre-kilogramme-second (M.K.S.) system in its rationalized form was adopted unanimously by the International Electrotechnical Commmission in 1950; and in April, 1952, the Council of the Institution of Electrical Engineers recommended that this system ‘should be employed by authors in papers submitted to the Institution and that all students of electrical engineering should become conversant with its use’. The rationalised M.K.S. system has, therefore, been adopted in this volume and, apart from the conversion table given on p. 383, no reference has been made to the C.G.S. electromagnetic and electrostatic systems.

The symbols and nomenclature are in accordance with the recommendations of the British Standards Institution and the Institution of Electrical Engineers; and for the convenience of students, the symbols and abbreviations used in this book have been tabulated on pp. …”

Third edition, published 1970

“In 1960 the General Conference of Weights and Measures recommended that the International System of Units should be universally adopted. This system is an extension and refinement of the traditional metric system. It embodies features which make it logically superior to any other system as well as being more convenient in practice: it is rational, coherent and comprehensive.

In this revised edition, references to British units have been deleted, but a Conversion Table has been added, giving the relationships between these units and the corresponding SI units. The changes also include the substitution of magnetic field strength and electric field strength for magnetising force and electric force respectively, and the use of the terms hertz, tesla and siemens. The joule is used as the unit of energy, whether mechanical, electrical or thermal, but the kilowatt hour is retained when the latter is the more convenient unit.”

Book 2

Fourth Edition, published 1969, third impression 1972

“The principal changes in this edition are concerned with nomenclature in order that the terms may be in agreement with the International System of Units (SI) adopted by the International Organisation for Standardisation and by the International Electrotechnical Commission. These changes have involved the replacement of mho by siemens, of weber per square metre by tesla, of cycle per second by hertz and of lumen per square foot by the metric unit lux representing lumen per square metre. Also, the unit of magnetomotive force is the ampere rather than the ampere-turn, and that of magnetising force (or magnetic field strength) is therefore the ampere per metre.

The joule should, in general, be adopted as the unit of energy, whether mechanical, electrical or thermal, but it is permissible to use the kilowatt hour when the latter is the more convenient unit.

The references to British units have not been deleted since these units will continue to be used-but to a diminishing extent-during the period of change-over to SI units.

In the 1972 impression, references to British units have been deleted except for a conversion table on page 695. The terms magnetising force and electric force have been replaced by magnetic field strength and electric field strength respectively; and an appendix on the generalised theory of electrical machines has been substituted for the trigonometrical and log tables. Also, for ease of reference, definitions of SI units are listed on page …”.

So there we are. In 1952 the IEE “recommended that this (metric) system ‘should be employed by authors in papers submitted to the Institution and that all students of electrical engineering should become conversant with its use’ ” (note the spelling of kilogram in the original text). By 1972 the change to SI in electrical engineering was complete.

Why then does the successor to the IEE, the Institution of Engineering and Technology (IET) now publish a periodical “E&T” that contains the usual hotchpotch of units that we in the UK are expected to tolerate ? Is there anybody out there who can provide an excuse on their behalf ?

They could use as an estimate the actual cost of the conversion in Ireland scaled up by the ratio of the number signs in the UK divided by the number of signs in Ireland.

You wouldn’t even need a calculator to figure that one out!

As for carnage, well such incidents would be comparativey rare and even then it would have to give rise to an accident before it counted as being a consequence of the change. I was not at all suprised that nothing was reported in the Irish press in 2005.

I remember the conversion in Canada well. Saturday night – all the speed limit signs in mph. Sunday morning – everything in km/h. Many cars at that time (1977) had mph-only displays, yet we still coped. Other cars had km/h-only displays, having been on sale since the beginning of that year, and, prior to the switch, we still coped. Today almost all cars have dual displays (even if, as has been mentioned here before, and certainly in my own case, the secondary km/h display is all but illegible)

The overnight switch to km/h had so little impact on safety that it was unmeasurable. IF there was any deterioration in accident rates due to confusion over the new speed limits, it was more than cancelled out by the better correlation of 10-km/h increments to prevailing road and traffic conditions. Police, for a while at least, were a bit more lenient in writing out speeding tickets, especially if you had an mph-only speedometer.

In, I would say, less than two months, people had forgotten what the old mph figures looked like – everyone had adjusted (I remember a work colleague getting a ticket in November 1977, just two months after the switch, and, in bemoaning her misfortune, never once reverted to mph).

Even more salient, the newspapers were notably completely silent on any safety concerns once it became obvious there weren’t any. It is a message that needs to be reinforced in very strong terms to counteract the use of this red herring by those who will oppose any idea of converting Britain’s road signs.

Maybe what I should be asking is what ‘networking’ and lobbying the UKMA engages in? Do they actively contact our leaders of large and high profile firms with UK based manufacturing e.g. Airbus, BMW, Honda, Rolls Royce? Has UKMA ever commissioned any research into the issue of our ‘metric muddle’ with any large employers? Has it ever carried out research in the UK among the population.

I would like to ask the UKMA what its actual strategy is to move the metrication issue on? We see a daily round of reports in the UK press that the country needs to have more scientists, innovators, engineers and skilled workers to rebuild our manufacturing base. We also see regular reports of declining numeracy in our schools. We know that as a country we are ever more reliant on overseas investments to maintain and improve our manufacturing base. To me, each of these factors on its own is a strong argument for the urgent completion of metrication. But together they are an absolutely cast-iron and compelling basis for a Government policy to complete metrication.

What is needed is for the concept of a link between the lack of metric progress and our steady decline to be floated. I am sure that if the public started to make this connection, they could possibly see the ‘bigger picture’ and the advantages of completing metrication in the UK. But who is going to move the argument forward? Is the UKMA engaged in this conversation? The only time the UKMA on TV is when they go ‘head to head’ with the BWMA. But the debate needs to progress beyond the level of the street market trader. It needs to be about the future of our country as a modern manufacturing base. It needs to be about the ability of the British people to see the ‘big picture’.

I must admit, I don’t know much about UKMA – does it have a staff & headquarters? Does it have a strategy document? How is it funded? If I knew a bit more about it and its long term plans I would be more than happy to pay a (modest!) monthly sub to try and support it?