I Machinery & Historical Background

Fig. 1 Brevet d’invention d’Abraham-Louis Breguet,Mécanisme d’horlogerie nommé échappement à force constante - Papier. 0,365 x 0,555 x 0,01 cm, 1798. Paris, Institut National de la Propriété Industrielle, inv. 1BA146 © Institut National de la Propriété Industrielle

Fig. 2 Swiss 14K gold minute repeater moonphase calendar chronograph circa 1890. 

The mechanism of a watch requires three elements: 

          1- a source of energy: from the earliest designs onwards, a timekeeping mechanism relies on the fundamental pull of gravity. For the clock the was a pendulum allowed a continuous and periodic supply of energy. For the watch, a winded spring stored energy in the tension of the spring which provided energy for a couple of months. 

          2- a brake and release mechanism: this was usually mediated by a cog, allowing the distribution of energy to be translated into successions of small motions as repeated series of starts and stops

          3- a regulating device: often called an escapement, this piece an integral part in equalizing the intervals of the start and stop motion, and was the central focus of scientific research for precision in the 18th and 19th centuries

The illustration Fig. 1 features an instructive illustration of a recently improved version of escapement, that of a constant energy escapement. One can see the metal rods pressed against the teeth of the central cog: the latter is the regulating device while the former is the brake and release mechanism. The metal rod accumulates a certain potential of energy to the point where it pushes against the tooth until it's flicked and the cog shifts over to the next tooth. 

These three crucial elements of the portable timekeeper was formally invented in the Middle Ages. The pieces merely had a minute hand to tell time with a 30 plus or minus accurate time, if the watch worked well. 


Introduced in 1675, the balance spring transformed the character of the watch, allowing a more accurate reading of time, fluctuating only by seconds. The two hands that we are familiar with today were brought to surface by 1680, as well as many other systems such as sun-and-moon dials, “wandering-hour” and calendars watches. This trend continued throughout the centuries, as illustrated in Fig. 2. The watch here above is a circa 1890 multifunctional pocket watch, including a chronometer, minute repeater, a moonphase calendar, and indicates the days of the week, date and month.

Horology by the end of the 17th century was proved indispensable for many fields, including astronomy, navy, even the military, where they used watches to calculate the rate of a flying cannon-ball…  

Royalty was the first to commoditize watches. The first kinds are said to be des tours de force, that is, to “impress and impose, not to tell time.” This technology, in its premature complexity, attracted royalty for its ornamental and conceptual aspects more than its practical function. Elizabeth I had a watch fitted into a ring with a tiny alarm that announced the hours by scratching her finger, reminding the queen her monarchic privilege of having time on her hands, literally.