# Watch glossary: T.

TACHOMETER or TACHYMETER
Function measuring the speed at which the wearer runs over a given distance. The tachometer scale is calibrated to show the speed of a moving object, such as a vehicle, over a known distance. The standard length on which the calibration is based is always shown on the dial, e.g. 1,000, 200 or 100 meters, or-in some cases-one mile. As the moving vehicle, for instance, passes the starting point of the measured course whose length corresponds to that used as the basis of calibration, the observer releases the chronograph hand and stops it as the vehicle passes the finishing point. The figure indicated by the hand on the tachometer scale represents the speed in kilometers or miles per hour.
A scale on the dial, flange, or bezel of a chronograph that, in conjunction with the second hand, gives the speed of a moving object. A tachymeter takes a value determined in less than a minute and converts it into miles per hour. For example, a wearer could measure the time it takes a car to pass between two mile markers on the highway. When the car passes the second marker, the second hand will be pointing to the car's speed in miles per hour on the tachymetric scale.
TANK WATCH
A rectangular watch designed by Louis Cartier. The bars along the sides of the watch were inspired by the tracks of tanks used in World War I.
TELEMETER
Telemeter scale allows to measure the distance of a phenomenon that is both visible and audible. The chronograph hand is released at the instant the phenomenon is seen; it is stopped when the sound is heard, and its position on the scale shows, at a glance, the distance in kilometers or miles separating the phenomenon from the observer. Calibration is based upon the speed at which sound travels through the air (approx. 340 meters or 1115 feet per second). During a thunderstorm, the time that has elapsed between the flash of lightning and the sound of the thunder is registered on the chronograph scale.
THIRD WHEEL
Wheel positioned between the minutes and seconds wheels.
TIMER
Instrument used for registering intervals of time (duration, brief times), without any indication of the time of day.
TIME ZONES
The 24 equal spherical zones unto which the surface of the Earth is conventionally divided, each limited by two meridians. The distance between two adjacent zones is 15░ or 1 hour. Each country adopts. the time of its zone, except for countries with more than one zone. The universal standard time is that of the zero zone whose axis is the Greenwich meridian.
TITANIUM
Titanium is an environmentally friendly, natural metal that is 40% stronger and 30% lighter than stainless steel. It is hypoallergenic because it is nickel-free. It is perfect for water sport enthusiasts as it is extremely resistant to salt water and other forms of corrosion and able to withstand extreme temperatures. Many titanium watches are further enhanced with a glass coating for increased scratch resistance.
TONNEAU
Particular shape of a watchcase, imitating the profile of a barrel, i.e. with straight, shorter, horizontal sides and curved, longer, vertical sides.
TOURBILLON
Device invented in 1801 by A. L. Breguet. This function equalizes position errors due to changing positions of a watch and related effects of gravity. Balance, balance spring and escapement are housed inside a carriage, also called a cage, rotating by one revolution per minute, thus compensating for all the possible errors over 360░. In a tourbillon (from the French word for whirl), the entire escapement is mounted on an epicyclic train in a "cage" and rotated completely on its axis over regular periods of time, usually once a minute. Although this device is not absolutely necessary for accuracy purposes today, it is still appreciated as a complication of high-quality watches.
TRAIN
All the wheels between barrel and escapement.
TRITIUM
Slightly radioactive material that collects light energy and is used to coat hands, numerals, and hour markers on watch dials in order to make reading the time in the dark possible. Watches bearing tritium must be marked as such, with the letter T on the dial near 6 o'clock. It is gradually being replaced by nonradioactive materials such as Superluminova and Traser due to medical misgivings and expected governmental regulation of its use.
TWO-TONE
A term use to indicate that a watch has both "silver" and "gold" tone color which may or may not be genuine gold or silver.

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## Related Questions:

### how do I use the moveable outer numbered ring on the t49825dh?

The numbered bezel can be used by divers to measure elapsed time on their oxygen supply. Place the zero where the minute hand is now and you'll know when 20 or 30 minutes have passed when the minute hand reaches bezel number 20 or 30.

In the same way, you can use the bezel to tell when 30 minutes have passed on your parking meter if you simply put the 0 on the minute hand when you leave the car. When the minute hand reaches the 30 mark, a half hour will have passed.

Typically, the bezel only turns counterclockwise to keep the wearer from bumping and changing the elapsed time number. On some less expensive watches, the numbered bezel does not turn and is decorative only.

Oct 23, 2014 | Timex Tiex en T49825DH Expedition Military...

### How to use Tachymeter in PL-12777JSBS model

Hi John
this model does not have a tachymeter only day date function on sub dials. there is a similar model 10962j which uses the same case this has the tacho function.

Dec 01, 2013 | Police Navy MF Mens Watch...

### HOW USE TACHYMETER & WHAT TACHYME3TER MEANS

A Tachymeter helps you estimate the speed you are going.

It uses the basic formula that speed = Distance/time

To use tachymeter, simply start the chronograph or stopwatch when the object measured passing the starting line. When the object reaches the next mile or kilometer marker, stop the chronograph or stopwatch. The point on the tachymeter scale that adjacent to the second hand of the watch indicating the speed (in miles per hour or kilometers per hour) of object traveling between the two points.

For example, we want to measure the average speed of a vehicle is moving. Start the chronometer or stopwatch function when the car passes the starting line, and stop the timer after the vehicle traveled exactly 1 mile or 1 kilometer. Then look at where the chronometer hand (the second hand of the watch) is pointing to, and get the reading or value of the corresponding number at the tachymeter bezel or dial. Let's say the stopwatch stop at 3 o'clock position, meaning 15 seconds had elapsed for the car to travel 1 mile or 1 kilometer. At 3 o'clock position, the tachymetre value shows that number of 240, which means the average speed of the vehicle was 240 mph or km/h.

### Source(s):

http://www.mydigitallife.info/2006/12/10...

Apr 02, 2013 | DKNY NY5045 Watch for Men

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