OVER the centuries, man has shown remarkable ingenuity in trying to answer that age old question, "How long is a piece of string?" At first the solution was usually sought by looking at the human body.
The ancient Egyptians, for example, used the "cub it" based on the length of the arm from the elbow to the finger tips. In Scotland on the other hand, so to speak King David I laid down around AD 1150 that an "inch" should be one third of the combined width of "the thumbs of three men; that is to say a mekill (big) man, a man of reasonable stature, and of a lytell man",
Across the border in 1592, it was decreed that the English yard was to be the length of Queen Elizabeth's "ruling arm". And, similarly, every European region developed its own individual idea of what a "foot" should be the shortest was the Hessischer Fuss at only 25cm, while the longest in Europe was the Paris foot at 32.48 cm.
As early as the 17th century, European scientists had recommended a decimal system of weights and measures.
But it was not until the fall of the Bastille in France that the political climate became right for its inception. A distinguished committee of five was established in 1790 to look into the matter and 202 years ago today, on April 7th, 1795, the newly devised "metre" was adopted as the official unit of length in the Republic.
The metre was defined as one 10 millionth part of the distance from the North Pole to the Equator - along the meridian of longitude running through - the city of Paris.
This was hailed as a natural unit, but later investigations showed that this distance, unfortunately, varies slightly, so the metre had to be redefined in less grandiose terms: it was specified as the distance between two marks on a platinum iridium bar to be stored in the Observatory of the International Bureau of Weights and Measures at St Cloud, near Paris.
This it remained until 1960, when it was further re defined in keeping with the modern age as 1,650,763.73 wavelengths in vacuo of the orange red line of the spectrum of krypton 86.
Napoleon's conquests, temporary though they may have been, facilitated the adoption of the metre in other European countries, and from those it spread around the world.
It is interesting, however, that in keeping with their revolutionary origins, the metre and the metric system were often adopted by countries during periods of political upheaval - notable examples being Latin America, China and the Soviet Union.