Fascination for the Ten

The most obvious dimension of the objects that surround us is the length. To measure it, taking a pattern length as a unit is enough. The election is arbitrary and every extension could be used. For example, the foot size. If we walk from one edge of a room to the other, making sure that the heel of the right foot always touches the end of the left one and always walking on a straight line, we should know how many feet are from one wall to the other. But if a friend does the same thing, we shall obviously find some differences: he likely has larger or smaller feet than yours and, therefore, the result of the measurement won't be the same. The room would have more or less feet of theirs than ours. Imagine that this example is repeated by many different people, so each measurement would be different. So, due to these discrepancies, it is required to have a "foot" of reference, a patterned foot.

"Use of the New Measures"




Let's take, for instance, the foot of the most important person. Perhaps a king's foot? Indeed, it could be made a mold from the king's feet, make thousands of copies of it and send all of them to all places of the kingdom to be able to proclaim "this is the good foot", "it is the right foot", "every disciple will use from now on the same measure". But in this situation, the patterns made from the king's foot must be very well preserved, so that they don't wear off and, also the replicas had to be extremely exact to avoid confusion. And what would happen if the king died? Probably, the new king would consider fair and necessary to substitute the "patterned foot" by his own, of course, and the process of making molds of his foot and making thousands of copies would have to be repeated, and all lengths which had been measured by the former king's foot, would have to be measured one more time, and this process had to be done with every new king, principal, bishop or any other mortal that could provide lengths.

Everything explained above could seem nowadays as a type of story for kids, and undoubtedly, it is. However, it is a fiction that has its element of truth. Very soon, the different countries and states discovered that the measuring patterns couldn't depend on anthropomorphic dimensions, so it was established as measures canonical lengths, pre-arranged, registered in some holy or very important place, but always arbitrary. The result was that each community, each city, each region, each state, disposed of a system of measures. The yards, the toises, the stadiums, the miles, the leagues, were all taken as units of length. What was the relation between them? Did they mean the same on earth and sea? In a community or in another? It is easy to imagine that the answer to all of these questions was a "No". The discrepancies between patterns of measure affected the trading, the prices of things, the inheritances, the establishment of boundaries, property rights, and so on.

Therefore, it is not a surprise what happened at the end of the 18th century in France. In the spring of 1789, on May 5, the General States of the French Kingdom met in Versailles. Called by king Louis the 16th, the representatives of all of those French social states had accumulated for months lots of notebooks filled with complaints, directed to the French court, asking to solve several problems in their societies. Among all of the presented complaints, it stood out one that nowadays doesn't seem to be really revolutionary, but at the time it was: the creation of a unique system of weights and measurements that would apply to all the French Kingdom, based on a natural magnitude, in other words, that didn't depend on any human contingency whatsoever. They asked for a universal unit of measure.

But, where could be found a natural measure of length that could be used as a reference? What relation should that measure had with its multiples and submultiples? It was not the first time that something of these characteristics was asked, something that meant eliminating the differences between regions, consolidated since the old feudalist system. The commissions of the Académie Royal des Sciences de Paris had previously been demanded the creation of a system of measures that wasn't linked to any tradition, had previously failed for the same purpose.

The representatives of the General States considered a priority problem to count with a system based on a unit of measure which didn't depend on human's will. Which could it be? Who and how would it be determined? Would this new unit have multiples and submultiples? Who would be able to carry out such work? So, politicians turned to the best scientists of the time. The process of decision-making wasn't exactly easy. In the first phase, they only compiled the etalons, the different measures of length and weight that existed back then in the Kingdom. From all French provinces, arrived in Paris the measures to be used as a reference, in order to establish the equivalents between the old and the new system.

In the Rapport sur le choix d'une unité de mesure, that Condorcet presented to the Académie Royal des Sciences, on March 19, 1791, it was suggested the measuring of a meridian segment, and it was also suggested as new unit of length: the ten-millionth part of the quadrant from the equator to the North Pole. The base of the system of multiples and submultiples would be the ten. The segment that should be measured was a meridian arc of 9 and a half degrees, specifically the one that goes from Dunkirk to Barcelona. This way, a new international dimension emerged to join two communities that laid at sea level. Moreover, the parallel of 45 degrees cut this meridian arc into two nearly equal parts.

The project had to meet the following proceedings:

  1. Establishing the differences in latitude between Dunkirk and Barcelona
  2. Measuring the bases
  3. Working out the triangulation from Dunkirk to Barcelona
  4. Observing the pendulum at the triangles' bases.  
  5. Verifying the weight of a volume of distilled water at 0 degrees Celsius (32 degrees Fahrenheit) according to the new units of volume. 
  6. Establishing the equalities between the old and the new units
After several frustrating attempts to form sub-commissions for boosting the projects, the Académie Royal des Sciences appointed two astronomers to carry out the tasks, Pierre François André Mechain and Jean-Baptiste Joseph Delambre. The former one focused on the Spanish part, that is, on working out the triangulation from Barcelona, and the latter one initiated the works in Dunkirk. The efforts were prolonged for 7 years and the narration of these would constitute one of the heroic scientific stories from the revolutionary period. 

Finally, a decree on December 10, 1799, determined which were the new units: of length, the meter, and of weight, the kilo; these had to be fabricated on platinum and they had to be spread throughout the entire Republic. Nowadays, the exact same copies of those measures are preserved in Paris. This decimal metric system was adopted very rapidly among the French and it was slowly spread throughout Central Europe and most of the new American republics. 

It was established not only measures but also systems of multiples and submultiples. The new form of measuring was related to the decimal numeric system. The multiples were the result of multiplying by powers of ten the pattern meter and the submultiples, the result of dividing by ten. The Republic started this way to use a decimal system.  

And what to do with measuring time, which traditionally was sexagesimal?

The next revolutionary step consisted of the renovation of the way of counting the hours. For the French revolutionaries, it was absurd that the day had 24 hours divided into periods of 12. Once conquered the meter, that subdivision of the time seemed very vulgar, and it induced the scientists to remember the "old regime", the old world. Also, the sexagesimal base was not natural because the Republic had to be decimal. Taking all of these things into account, the schedule should be entirely decimal: a day divided into groups of 10 hours; an hour, ten minutes, a minute decimal multiple from seconds. 

Up to this day, one can observe decimal clocks in Parisian museums and in some private collections. However, the Republic was never able to change the traditional system of time. Can you imagine the project of substituting all public clocks from all official buildings, from all churches,? converting all watches owned by private people into useless pieces of metal? the industrial effort which would mean fabricating such quantity of decimal clocks? The rhythm of the days, the references from ancient times had to be translated into the new decimal system of time. That was nearly impossible. 

Imperial System of Weights and Measures

When talking about the metric system often emerges the question of why this system hasn't been imposed in all places of the world, a system so rational, so easy to remember and to use, so "natural". Why an important part of the population hasn't showed the fascination for the number ten? Why the miles, the yards, the inches are still used, instead of the centimeters, meters, and kilometers? Why the gallons were not substituted by the liters?

These are questions that cause one to think about the Anglo-Saxon world, which didn't adopt the metric system even though their numeric system is also decimal as, with some exceptions, people had 10 toes and 10 fingers. This is why, the world where the French system has triumphed (the entire European continent, a large part in America, Africa, and Asia), considers the Anglo-Saxon world an anomaly. However, that opinion doesn't agitate the supposed "freaks". Instead, they make fun of it. 

Answering the question of why the British didn't welcome the decimal metric system is as difficult as responding to any negative question. However, there are some clues about this decision. Great Britain was already a large empire that was expanding its borders when the new decimal system showed up and started to be slowly adopted by the continent. They disposed of an imperial system of measures, well arranged, relatively safe and the trade made use of this system with outstanding efficacy. Also, they knew that every political system constituted in the form of an empire, had its domain based on the imposition of a system of weights and measures to the colonies. In fact, even the hated American colonies had adopted the system after having achieved independence. 

Once a system of measures, whatever it is, proves its efficacy, it is difficult to find reasons to migrate to other system, unless it threatens the aim for which it was created: to facilitate the interior communications between both sides on trading, industry, and law and the disposal of a reasonable translation capacity of the other systems. During the 19th century, those European and American nations, which adopted the metric system found advantages in doing so, as they were used to using local and confusing systems of units. That was not the case for the British Empire, where the imperial system had proved its efficacy. In fact, nowadays exist two systems, the decimal and the imperial, coexist and their communication abilities have allowed them to be compatible with each other. They both have become important features of the cultural idiosyncrasy of their communities.