In his recent article “Why I …”, Ronnie Cohen looked at the present to explain why he believes the UK should complete the transition to metric units. However, some of those who commented on his article also looked back. In this article, I take another look into the past and then ask if the fading of such memories might prolong the measurement muddle.
At my primary school in the early 1950s, we celebrated Empire Day (in late May), and we were taught imperial, not metric, measures. The backs of the school-issue exercise books were printed with tables of imperial measures which served only to confuse – pecks and bushels, chains and cables, fathoms and furlongs, pounds (avoirdupois), ounces (troy) and ounces (fluid), miles (statute) and miles (nautical), and on, and on. Needless to say, imperial ruled on the sports field: the 100 yard sprint, the 4 x 110 yard relay and the mile come to mind.
The first science lesson in secondary school brought a surprise. The teacher, brandishing a metre rule, told us that there was an alternative system of measures, that scientists used it, and henceforth so would we. Even so, lessons were not entirely free of the measurement muddle. When we started a subject called applied maths in the sixth form, we reverted to imperial. The poundal, a unit which was not in those tables on the back of the exercise books, put in an appearance. New factors had to be learned, like 1 pound force is 32 poundals and 60 mph is 88 ft/sec.
Foreign travel by teenagers was the exception rather than the rule in the late 1950s. So a visit to Denmark in 1959 produced another surprise. This metric system, with which we had become familiar through our science lessons, was in everyday use in homes, in shops, and on the street. And it seemed to work just as well in those situations as the imperial system did in Britain.
University compounded the educational confusion. Some subjects like structural design, fluid mechanics, and thermodynamics were taught in imperial. Stresses and pressures were measured in tons/sq ft, or pounds/sq in or pounds/sq ft depending on the application. New units were encountered, such as slugs, kips and °R. Other subjects were taught in metric, such as electrical technology. Soil mechanics managed to combine laboratory work in metric with theory and design in imperial. And on our field surveying course we came across the engineer’s chain of 100 links (literally), each one foot long, and the surveyor’s chain of 22 yards.
Then on to the world of work – a job on a construction site, and new variations on the imperial theme. The levelling staff was graduated in hundredths of feet, not inches and eighths, to facilitate the subsequent calculations, but measuring tapes were in feet, inches and fractions. Measurements of excavations were made in feet and inches, but volumes were calculated in cubic yards. Arcane tricks, doubtless going back to the Victorians, were used to convert one to the other, as pocket calculators were still unheard of.
Happily (for me at least) this muddle did not last long. In 1969, the construction industry announced it would go metric, following the lead from government. In a single leap, we would switch from imperial to SI, by-passing the metre-kilogram-second system (MKS) and metric technical units. Before long, new measuring scales and design tables were being handed out by the boss (I was in the design office by then), the first metric job arrived, I heaved a sigh of relief, and that was that. An era had ended, or so it seemed.
Today, those who are focused on their particular areas of interest and determined to resist change, including market traders and successive UK ministers of transport, try to persuade us that their inertia has little impact on the wider economy. In response, some like Ronnie point out that completion of the metric conversion in the UK would make all our lives so much easier. Others like me look back. Will our fading of memories of the measurement muddle of forty or more years ago reduce the drive to finish the job? Indeed, is there now a generation gap? And one wonders what future generations, accustomed to a metric world, will make of it all.
It is interesting to note one impact of the metric changeover on the construction industry. As the UK government foresaw in 1965, markets for design in imperial units in countries of the former British Empire shrank steadily during the 1970’s. Equipped with skills in SI, the new worldwide standard system of measurement, British consultants were able to maintain and expand their businesses abroad. Arups became established in China for example, and Norman Foster won the design competition for reconstruction of the Reichstag in Berlin and also assisted with the Millau Viaduct in France. Today, in a strange twist, British consultants find themselves takeover targets of US companies facing declining markets for design in US customary units.