The Weird Origin of ‘Chronometer’ and What It Means for Watches Today

Humpty Dumpty famously says, in Alice In Wonderland, that words are nothing more than pieces in a game, where you can change the rules any time you want. “When I use a word,” he says, “it means just what I choose it to mean – neither more nor less.” To which Alice replies, tactfully if skeptically, “The question is…whether you can make words mean so many different things.” In all of watchmaking there’s probably no word that this applies more to than “chronometer,” which first burst on the scene in 1714 – or so many people think – and has been shape-shifting ever since.

Now, you don’t have to spend much time around fake watches before you figure out pretty quick that a chronometer is not a chronograph. The latter, of course, is basically a combination of a fake watch and a stopwatch; the former, at least nowadays, is a watch which – assuming it comes from an ISO-standards compliant country, which Switzerland is – has been certified by an independent examination board and found to meet certain minimum standards.

That officiating body today is the (in)famous Controle Officiel Suisse des Chronomètres, better known to Watch Idiot Savants the world over simply as the COSC. In its current form the COSC has been around since 1973, but prior to that, testing took place at the so-called Bureaux officiels de controle de la marche des montres, which in horological literature are generally more concisely referred to as the BO agencies. There were different numbers of these at different periods in history; one of the oldest, in Bienne, was founded in 1877. It was these agencies that were responsible for providing independent testing of replica watches uk seeking chronometer certification, until they were put under central administration and dubbed the COSC in 1973.

COSC standards for mechanical watches are pretty straightforward. For most watch enthusiasts, the most relevant standard is the one for average daily rate over a 10 day testing period; for a watch to pass, it must maintain an average daily rate of -4/+6 seconds. Rolex used to get flak now and again for calling its watches “superlative” chronometers on the dials, but in 2015, the Crown introduced the new Day-Date 40, along with a new Superlative Chronometer internal certification, requiring a daily rate of -2/+2 maximum per day. In 2016, Rolex announced it would extend this to all Rolex watches moving forwards.

That’s the gist of it for the 20th and 21st centuries. In the 19th century, however, as you go back, you start to see the meaning of the word change as you look further and further back at its usage and evolution.

Above is a key-wound, high-grade pocket watch made by Girard-Perregaux for the English market, dating to about 1860. We looked at the technical features of this watch last January, and one of those features is directly relevant to the history of the term “chronometer” (which you can see engraved on the movement dust cover above – with the English rather than French spelling, as this was an English market watch).

That technical feature is the escapement of the watch, which is what’s called a detent escapement. The detent escapement was, as far as we know, invented by French horologist Pierre LeRoy in 1748, although the first practical version of the escapement was the pivoted detent escapement of John Arnold in 1775. Arnold’s contemporary in England, Thomas Earnshaw, was responsible for developing the version of the detent escapement that came to be most widely used, and below you can see the basic layout of the spring detent escapement, as it’s shown in the 1896 edition of Britten’s Clock and Watchmaker’s Handbook.

It’s kind of fascinating to think, though, that the two earliest known uses of the word came from such different contexts. One was a serious text on the evidence for a divine hand in the structure of the universe. But the other, almost-first use of a word that became synonymous with precision timekeeping, and which represents a major marketing point for every brand that uses it today, was in what may have been a satire.