Milton explained that rhyme was “the Invention of a barbarous Age, to set off wretched matter and lame Meter,” so of course he didn’t need it. No more do I need his explanation, only his phrase, to introduce a delightful book, Les Origines du Système Métrique (The Origins of the Metric System), by Adrien Favre, Professeur au Lycée du Toulouse—which means a high-school teacher in a provincial city, then of a couple of hundred thousand people, far from Paris—published in 1931.

“Before the establishment of our Metric System,” he begins, “there reigned in France, among the units of measure, an incredible confusion.” Naming twenty-two of them, he invites us to think of Rabelais’s lists, and then reveals that the twenty-two were merely the subdivisions of the agrarian measures in one area of the country, Haute-Garonne—a place where, while the measures themselves had only five different names, these designated forty-three different actual measures.

He goes on to quote the great Lavoisier. “One is terrified when one considers that in the subdivision of Péronne alone, which is moderate in extent, there are seventeen different journaux; that the majority of these journaux are composed of perches of different sizes; that the pieds which enter into the composition of these perches not only are not of the same length, but even contain different numbers of pouces, which are themselves not of the same length.” Here a journal is an agrarian unit, somewhat larger than an acre (originally, what might be worked in a day, or journée), and pied and pouce are respectively the French foot and inch, similar to the English.

Such examples can be multiplied almost beyond measure, and what is true of length and area is equally true of volume and weight. If the names make us think of Rabelais, the want of system recalls Descartes’s account, at the beginning of the second part of his Discourse on the Method, of ancient cities which have grown up without rational plan: their irregularity, inharmonious juxtaposition of buildings, and crooked streets look like the work of chance. Paris was one of those, until Baron Haussmann corrected it in the nineteenth century, the age in which the newly established Metric System was doing away with the absurd wealth of local units. The old city had charm and character, but was dangerous and insalubrious; the old Rabelaisian measures not only terrified scientists like Lavoisier, but presented extraordinary obstacles to commerce. Hence “‘The thought of establishing in France the unity of weights and measures is perhaps,’ says Dareste, ‘as old as the monarchy.’ But in this matter, the history of the efforts of the monarchy is the history of the good will shown powerless,” for the problem of what units to choose and how to impose them on France—the place of which De Gaulle asked, “How can you govern a country which has two hundred and forty-six varieties of cheese?”—was measurelessly complex. Only with the fall of the king was the rule of a single system of measures put in place.