A global measurement system

Dr Peter Saunders explains how the Industrial Revolution and advances in science furthered the need for an accurate universal system of measurement.

Discussion point: Even though the Industrial Revolution began in Great Britain, why do you think they wanted to stick to their own units of measurement rather than sign up to the Metre Convention?

Transcript

PETER SAUNDERS

The early 1900s saw the Industrial Revolution – so it was huge amounts of industrialisation and new technologies, new developments occurring. People were developing railways, and there was steam navigation and there was sort of massive advances – people were manufacturing huge bits of machinery. And they had to source different parts from different suppliers, so of course you always want one man’s nuts to fit another man’s bolts. All sorts of scientific things going on– scientific discoveries happening – better accuracy was required.

And so it was finally realised that they needed some universal system of measures that everybody could use. So in 1875, on the 20th of May, which is World Metrology Day, representatives from 17 countries around the world gathered together in Paris and signed what was called the Metre Convention. It is also known as the Metric Treaty. Essentially, that was an agreement to use the metric system. So originally I said there were 17 countries that signed up. Interestingly, the US was one of the first countries to sign up, even though we think the US still uses imperial units. In fact, in government and science organisations in the US, they do use the metric system – really it’s only out in industry that they use the imperial units.

If you think back to the Trafalgar Square thing – remember I said the plaques were installed in 1876 – it was the year after the Metric Treaty was signed, so obviously the UK didn’t sign it – at least not originally. They wanted to stick to their own units, but they did relent. A few years later in 1884, the UK signed the Metric Treaty. Australia signed it in 1947. Can anyone guess when New Zealand signed it? We are a member. No guesses? [1948] You’re miles out. It was 1991. It was only fairly recently that New Zealand signed it. So these days, there are 64 members of the Metric Treaty, and 43 are what they call associate members.

So as well as agreeing for everyone to use the metric system, the Metric Treaty also created an organisation called the BIPM, which is the International Bureau of Weights and Measures in Paris – there’s a photograph of the site – and the BIPM is responsible for co-ordinating worldwide metrology and sort of overseeing developments of the metric system. Interestingly, the site is just south of the Seine River near Versailles, sort of on the outskirts of Paris, but the site it is on is not technically part of France. It is independent territory, so this is an intergovernmental organisation and it sort of has its own sets of rules, but you don’t need your passport to enter the gates.

Acknowledgements

This video clip is from a recording of a presentation by the Measurement Standards Laboratory of New Zealand (MSL) in celebration of the redefinition of the International System of Units (SI), which happened on 20 May 2019. The presentation by Peter Saunders and Farzana Masouleh of MSL was filmed at Unleash Space, Faculty of Engineering, Auckland University.

Filming and editing by Jonathon Potton of Chillbox Creative. MSL produced these videos to share the story of metrology development.