Skip to content
The Encyclopedia of Horology

Complication · Timing

Chronograph

Partially verified

A watch with an independent stopwatch function layered on top of ordinary timekeeping, started, stopped and reset by pushers, typically displaying elapsed seconds and minutes (and sometimes hours) on subsidiary dials.

Definition

A watch with an independent stopwatch function layered on top of ordinary timekeeping, started, stopped and reset by pushers, typically displaying elapsed seconds and minutes (and sometimes hours) on subsidiary dials.

Historical origin

Early timing devices attributed to Louis Moinet (an example dated to around 1816, per Moinet's own records, is described by some historians as the first chronograph) and to Nicolas Rieussec, who patented a chronograph mechanism in 1822 for timing horse races; both attributions are discussed in the literature and the exact 'first' remains debated.

How it works

A chronograph adds a separate friction-driven chronograph wheel to the going train, engaged and disengaged by a clutch (commonly a horizontal coupling wheel or, in more modern designs, a vertical clutch). Pressing the start pusher engages the clutch so the chronograph seconds hand begins to run.

A column wheel or cam-based switching mechanism coordinates the start, stop and reset functions, ensuring the various levers (coupling, hammer, brake) move in the correct sequence and cannot jam if pushers are pressed out of order.

Stopping disengages the clutch and applies a brake to halt the chronograph hand instantly; the reset pusher drops hammers onto heart-shaped cams (coeur pieces) on the chronograph seconds and minute-counter arbors, snapping them back to zero.

Pocket watch context

Chronograph pocket watches were widely produced from the mid-nineteenth century for sporting, medical (pulsometer) and railway timing use, often as separate 'stop watches' rather than combined timekeeping-and-timing pieces.

Wristwatch context

One of the most commercially important wristwatch complications, ranging from simple two-register chronographs to elaborate column-wheel, vertical-clutch and flyback designs used in motorsport, aviation and diving contexts.

Identification

  • Two pushers flanking the crown (start/stop and reset)
  • A running seconds/minute-counter subdial layout distinct from ordinary small seconds
  • Column wheel visible on the movement as a small fluted turret, versus a flatter cam-switching mechanism

Servicing notes

Chronograph mechanisms are among the most failure-prone complications to service badly — incorrect reassembly of the column wheel, hammers or clutch commonly causes a jumping or non-resetting hand. This work should always go to a watchmaker with specific chronograph experience.

General guidance only. Complicated mechanisms should be assessed and serviced by a qualified watchmaker or clockmaker specialist, not adjusted at home.

Photographs

Pocket Chronograph (48709445542)
Pocket Chronograph (48709445542) — Auckland Museum Collections from Auckland, Aotearoa New Zealand, CC BY 2.0. Wikimedia Commons file page
Pocket Chronograph (48708940993)
Pocket Chronograph (48708940993) — Auckland Museum Collections from Auckland, Aotearoa New Zealand, CC BY 2.0. Wikimedia Commons file page
Pocket Chronograph (48709439862)
Pocket Chronograph (48709439862) — Auckland Museum Collections from Auckland, Aotearoa New Zealand, CC BY 2.0. Wikimedia Commons file page

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Moinet, L., attribution discussed in Habsburg/auction-house horological histories
  2. Rieussec, N., 1822 French patent record
  3. Attribution of the 'first' chronograph is disputed between Moinet and Rieussec in the secondary literature.

Where sources disagree, the disagreement is stated rather than resolved silently.