Cronographs: watches needed to measure and to “write” time intervals

Etymology of the word “chronograph”: from ancient Greek “chronos”, the time”, and “graphein”, to write.

Do you think this is only a metaphor of the clock’s hands ability to draw the time thanks to its movement? Actually, there is less poetry and more rationality than expected.

The word chronograph was introduced to describe the first clock able to measure time fractions. It was produced in Paris in 1820 by the French watchmaker Rieussec. Differently from contemporary chronographs, time measurement was not supported by the start and stop of the second’s hand… mechanically too difficult at that age. The time interval was measured thanks to the ink signs on the dial left by the second’s hand.

The chronograph’s second hands had a small opening on which some ink was stored. To measure the length of an event it was necessary to push a button that forced the second’s hand to touch the dial, signing it with an ink dot. While the second’s hand followed its run, the passed time from the black dot could be red.

Certainly the reset mechanism was not as efficient as the current is… in order to make a second time measurement, it was necessary to open the clock and to clean the dot on the enameled dial.

One of Reussiec clocks is exhibited at the Patek Philippe Museum in Geneva.

Tags: Did you know... Watch history