Glossary

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Tachometer
Instrument for measuring speed. In watchmaking, a timer or chronograph with a graduated dial on which speed can be read off in kilometres per hour or some other unit (see timer).

Terminage
French term denoting the process of assembling watch parts for the account of a producer.

Termineur
French term for an independent watchmaker (or workshop) engaged in assembling watches, either wholly or in part, for the account of an «établisseur» or a «manufacture», who supply the necessary loose parts.

Tin glazing
In contrast to conventional barrel polishing, in which the parts to be polished are placed in a rotating barrel full of stones, in the case of tin glazing, the movement parts are polished using a tin rod, which is moved by hand evenly across the surfaces to be polished.

Tourbillon
Device invented to eliminate errors of rate in the vertical positions. It consists of a mobile carriage or cage carrying all the parts of the escapement, with the balance in the centre. The escape pinion turns about the fixed fourth wheel. The case makes one revolution per minute, thus annulling errors of rate in the vertical positions.

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Vibration
Movement of a pendulum or other oscillating element, limited by two consecutive extreme positions. The balance of a mechanical watch generally makes five or six vibrations per second (i.e. 18,000 or 21,600 per hour), but that of a high-frequency watch may make seven, eight or even ten vibrations per second (i.e. 25,200, 28,800 or 36, 000 per hour).