If the current Government implement their proposals to remove the requirement to use metric units for trade, it will be the first reversal of metrication in the UK and probably the first reversal in Europe since the days of Napoleon over 200 years ago.
France was the first country to introduce the metric system to replace a bewildering number of different measurement systems used across the country. They introduced it during the French Revolution in the late eighteenth century. This was accompanied by a public education campaign to familiarise the general public with the new measurements. The French Emperor Napoleon saw the metric system as an inconvenience and the populace continued to use the old measurements. For these reasons, Napoleon issued the imperial decree of 12 February 1812. He introduced the mesures usuelles (customary measures) where old units were redefined with rational metric sizes.
Under the mesures usuelles, the following units were redefined as follows:
- toise (fathom) = exactly 2 metres
- aune (ell) = exactly 120 centimetres
- boisseau (bushel) = exactly an eighth of a hectolitre
- livre (pound) = exactly 500 grams
In the mesures usuelles system, these newly defined units plus the litre, the metric unit we are all familiar with, were divided as follows:
- The toise (fathom) was divided into 6 pieds (feet) and 72 pouces (inches). The pouce was divided into 12 lignes (lines).
- The aune (ell) was divided into the demi aune (half an ell) and the tiers aune (third of an ell).
- The litre was divided into demis (halves), quarts (quarters or fourths), huitièmes (eighths) and seizièmes (sixteenths).
- The boisseau (bushel) was divided into the double-boisseau (double bushel), demi-boisseau (half bushel) and quart-boisseau (quarter bushel).
- The livre (pound) was divided into 16 onces (ounces), each once was divided into 8 gros and each gros was divided into 72 grains (grains).
Ever since the Weights and Measures (Metric System) Act legalised metric measures for ‘contracts and dealings’ in 1864, the UK has never gone backward on metrication. The UK has made erratic progress on metrication, sometimes making a lot of progress, such as the 1960’s and 1970’s after the start of the UK Metrication Programme in 1965, and making little or no progress at other times, for example, since the year 2000.
It is hard to think of other reversals of metrication because they are rare. John Frewen-Lord has commented on Canada’s reversal of metrication under huge pressure from the USA when Brian Mulroney was Prime Minister of Canada. You can read his comments in these past MV articles:
The outcome of these measures was to make Canada’s unsatisfactory situation worse. Like the UK, Canada is still in a measurement muddle. It is not an example to follow nor is Napoleon’s imperial decree of mesures usuelles.
If the Government is looking at mesures usuelles as an important precedent, they will be disappointed to learn that the reversal of metrication was not permanent and ended in one generation. Twenty-five years after Napoleon’s imperial decree, King Louis Philippe I revoked the use of traditional and customary measures by the law of 4 July 1837. This came into force in 1 January 1840 and the metric system was fully reinstated. This ended the use of mesures usuelles.