The Metric Revolution

When a French traveler visiting the Soviet Union shortly after World War I lavished praise on the universal applications and benefits of the meter, his Russian hosts laughed in disbelief at the foreigner’s stupidity: “As if the centimeter could measure our Russian roads!” This would be as much folly as making Russian vodka out of French grain.

We don’t understand the Russians’ reaction. Today we think of weights and measurements—if we think of them at all—as something natural and neutral. They are simply categories used to facilitate trade and calculations with no inherent values or ideology of their own. Yet our notion of weights and measures would have been extremely alien and troubling not only to those dumbfounded Russians but to most people throughout time. Measurements are the result of historic processes, social struggles and conceptual revolutions.

Most measures have been anthropomorphic. People measured with their arms (the fathom), their hands (span), their feet (feet), and their elbows (the el). They also measured according to their strength, sight or hearing. Nomads in the Sahara Desert, to whom the distance to the next oasis was a matter of life or death, used categories such as a stick’s throw, a bowshot, the distance one could see from level ground, and how far one could see from a camel’s back. Latvians used the distance one could hear a bull bellow.

Agricultural peoples measured their land by its usefulness, not abstract dimensions. In France the argent was the area that one man with two oxen could plow in a day. This of course would vary according to terrain, rocks and trees. Many other measures similarly were scaled to the amount of human labor needed to prepare land for harvest. In pre-capitalist societies with no functioning land market, this was the relevant calculation.

Productivity figured in places ranging from Brazil and Colombia to France and Italy to Japan. A unit of land was often determined by the amount of seed it produced. Thus the same unit might cover very different dimensions of territory and indeed might vary from year to year. For subsistence farmers, the size of the harvest was a much more important statistic than the dimensions of land worked.

These measures, even sometimes when they had the same name, varied tremendously in size. One department of France had nine different sizes of argent; the largest was five times the size of the smallest.

The use of very many different weights and measures resulted in good part from small, compartmentalized economies with little intercourse and strong senses of tradition. Local measures were the product of local feuds and struggles, were understood locally, and helped people define who they were and who was the “other.” Change was considered subversive; new measures were seen as means of cheating producers or consumers who were not familiar with them. Populations were barely numerate and did not even all use the same numerical system. In the early modern world, systems based on 20 (the number of toes and fingers) were more common than systems based on 10. Anything more than simple division was mysterious, so translating from one measure to another was extremely difficult and suspect.

The plethora of measuring systems was not simply a result of folk wisdom (or ignorance), however. For thousands of years weights and measures were seen as attributes of justice and sovereignty. Authority meant the power to define the scales. When the definer of measures was also the tax collector and lender, abuse often followed.

In pre-revolutionary China there were two dou that differed by more than a third. Officials often used the larger to collect peasant dues and the smaller when lending grain. Under feudalism each lord set his own standards and his court judged them. This complexity was compounded in places such as Silesia where in addition to the multitude of small seigniorial potentates, there were church and municipal authorities, each with their own weights and measures.

The definition of measures sometimes varied intentionally to hide price differences. Great changes in price were unsettling for pre-capitalist peoples to whom difference might mean the difference between life and death. Often they responded not by going to a different seller, but by revolting. To avoid this, merchants often varied the measures. In pre-metric Europe, an apothecary’s pound was minuscule, the spice merchant used a larger pound and the butcher a larger one yet. In the Piedmont of Italy in 1826, merchants agreed on using the libra. However, for sugar, coffee and groceries it weighed 12 Milanese ounces, for candles 14 ounces, good quality meat and cheese used 32 ounces. Bread, the most important and politically charged food in early modern Europe, was sold by the loaf. The price remained the same, but like today’s candy bars, the size of the loaf varied substantially depending on the price of grain. As the Polish historian Witold Kula insightfully observed: “It is reasonable to look upon the whole process, within limits, as a safety valve or a buffer against social reaction to market developments.”

The first three major efforts to unify measures were by-products of attempts by the Greeks, Romans and Charlemagne to spread and solidify their empires. The need to expand tax collection drove these attempts. But since they did not reflect or create any revolution in local perceptions, they largely failed.

Success only came at the end of the eighteenth century when French revolutionaries created and spread the metric system. Based on impersonal and unvarying astronomical calculations (the meter is one ten-millionth of the distance along a meridian from the equator to the pole) rather than local anthropomorphic usages, the meter required a revolution in thought: acceptance of the notion that all people are equal before the law, that is, that the law-giver or measurer not be arbitrary; and development of the process of commodification. As goods became produced for a distant market they lost the distinctiveness bestowed by the individual producer or consumer, becoming mass products with common attributes that could be measured.

As goods became commodities and their attributes were abstracted in measurable quantities, they became fungible, commensurate. This protected peasants from arbitrary local officials or merchants but destroyed the business of many international traders. Only the traders had been able to understand the plethora of local weights and measures and had been able to translate between them. Once their skills were no longer needed, their pivotal position was taken over by large-scale importers in the biggest consuming markets. Measures ceased symbolizing local history and traditions, struggles and victories, and became the mundane boxes and scales we think so little about today.