Once upon a time, the chronograph was a marvel of mechanical ingenuity. I know, it’s hard to imagine that these days, given that every watch brand worth the name (and plenty that aren’t) have their own spin on the stopwatch functionality of a chronograph. Despite being one of the most common and genuinely useful things a watch can do, it’s also one of watchmaking’s more complicated, one that has been developed over centuries to the point that we take it for granted today. So, as we delve into the history of the chronograph and how they work, let’s start with the big question…
Who Invented the Chronograph?
Louis Moinet’s pioneering chronograph, Compteur de Tierces (1816)
Tragically, Louis Moinet has only been credited with inventing the chronograph or rather more correctly a compte-tierces (thirds counter), since 2012. Instantly recognisable to a modern audience, the remarkable pocket watch from 1816, arguably the first chronograph in history, ran at an almost incomprehensible 30Hz – 216,000 vibrations per hour – and was able to record intervals of 1/60th of a second. From the dial layout to the use of start/stop and reset pushers, this was, for all intents and purposes, the first chronograph.
Rather confusingly, the first literal chronograph was invented a few years later by either Nicolas Reiussec or Frederick Fatton (a student of Abraham-Louis Breguet), depending on where your loyalties lie. Both claim to have built the first inking chronograph, a device that marks the dial with an ink spot to record the elapsed time in seconds (hence chrono-graph).
Longines developed the calibre 13.33Z, the first ever chronograph movement to be placed inside a wristwatch (1913)
At this point in history, chronographs were either pocket watches with start/stop functionality or boxed-up specialised timers. In terms of wristwatches, the first was Longines in 1913, with a monopusher and stopwatch function accurate to 1/5 of a second, before Gaston Breitling took the reins with the first separate chronograph pusher just two years later.
Breitling Chronograph Advert (1933)
There’s some fogginess around the first recorded two-pusher, flyback chronograph, as there often is with historical movements, with a Longines potentially in the running. It’s generally accepted that the first was from Willy Breitling (son of Gaston), who in 1933 Breitling created the two-pusher chronograph that has since become the norm across the watch industry, still 90 years on. Although early watchmaking records being what they are, that’s not necessarily the case. In 2020 a Longines 13.33Z was discovered that was both an earliest two-button chronograph and the earliest flyback, predating the brand’s own patent. As Longines, unlike Breitling, made their own movements at the time, this is easily believable.
How Does A Chronograph Work?
Longines 13ZN Chronograph (1936), image credit: Analog:Shift
Chronographs tend to share a similar mode of action – one or more pushers, usually either side of, or incorporated into, the crown, and used to control the start/stop and reset of the timekeeping mechanism. In what has become the standard layout, the top pusher controls the start, releasing the brake that is attached to the seconds counter and resetting the hammers (to prime it for the stop function). Most importantly, it engages with the gear train, via a clutch system or rocking pinion, to start the recording period.
A. Lange & Söhne calibre L951.5 uses a column wheel
In order to function in the correct order, the watch needs to ‘know’ where it is in the start/stop/reset series of actions. This can be controlled by a column wheel (a crenelated turret-shaped piece) that interacts with the coupling clutch/pinion to operate the chronograph. The coupling dips in and out of the crenelations as the top pusher is depressed, engaging the running of the chronograph, or disengaging the gears, and is held in place by a detent spring.
Many owners of classic column wheel movements, such as the Valjoux 72, describe the smooth action of this mechanism, especially when compared to the simpler lever cam calibres, like the Valjoux 7750. The latter has a rocking pinion and cam that needs to be pushed into place, and can often feel much heavier to use.
Valjoux 7750 calibre uses a rocking pinion and cam that needs to be pushed into place
While there is much to be said for the column wheel, and its use of either a horizontal or vertical clutch (where the start/stop/reset cams are stacked into a single unit), the Valjoux 7750 and similar chronograph calibres have a lot going for them. Their components can also be manufactured relatively simply, and potentially more cheaply, especially when compared to the more complex, vertical elements of the column wheel and its associated teeth. The accuracy of these two types of mechanism is also broadly similar – although there are some important differences.
A. Lange & Söhne Datograph ref. 403.041F uses a horizontal clutch, image credit: Sothebys
The chronograph function uses the same gear train as the watch to drive the sweep seconds hand and the minute counter via a series of wheels. In watches using a horizontal (or lateral) clutch, an intermediate wheel engages with the fourth wheel; this is an indirect coupling between a moving and a stationary wheel, and therefore has the potential to ‘stutter’ when the start pusher is depressed. This may lead to a decrease in accuracy, as the teeth on each wheel need to mesh in order to drive the chronograph, and this additional drag can impact the watch’s timekeeping and (potentially) cause damage to the fourth wheel. This hasn’t stopped Patek Philippe or A. Lange & Söhne using a horizontal clutch – the latter in the superlative L951.1.
In chronographs with a vertical clutch, there is a permanent connection, and the clutch is more akin to one you might find in a car. This removes some of the disadvantages of a lateral clutch, and is more accurate, although these movements tend to be more complicated (employing a series of springs) and therefore more expensive and difficult to service. Given most watches run at four hertz, however, it’s unlikely that many people will be able to notice this improvement in timing ability.
What is the Future of Chronographs?
The Agenhor Carpe Diem is the only timepiece made by Agenhor himself that uses the AGH-6361 movement, a clock made for Only Watch 2017
Perhaps the most interesting development for chronograph history in recent years has come from Agenhor SA, which developed the catchily-named AGH-6361 ‘Agengraphe’ automatic chronograph in 2017 – subsequently adopted by other high end watch brands like MB&F. This calibre was designed from the ground up to remove the perceived weaknesses inherent in all chronographs, such as those mentioned previously, and uses a column wheel and form of lateral clutch that is unlike anything else produced to date. As with the vertical clutch, this annular movement uses friction to drive the chronograph, using a toothless wheel to push against a second toothless wheel on the fourth wheel. This pressure is maintained by a rather beautiful ‘tulip’ spring, that maintains the appropriate amount of pressure to transmit the energy to drive the chronograph.
While this calibre is almost bewilderingly complicated to describe, it is also rather beguiling. This extends to the dial layout and use of hands, which are all centrally mounted, including the elapsed time, due to the ingenious ring-shaped movement (and hidden peripheral automatic rotor). The Agengraphe represents, perhaps, a ‘best of all possible worlds’ solution to almost every question that’s ever been asked of a chronograph.
