Box chronometers

[Dr. Jon]

Are box chronometers watches or clocks?

The arguements are that they watches are they are fully portable and use spring power and spring regulation.

Many clock people regard Chelsea "clocks" as watches.

On the other hand there are carraige clocks and simple ones to my knowledge have always been considered clocks. To my knowledge no one has worn a box chronometer as a personal time piece. These factors suggest that they are clocks.

I also know some clock types who regard anything with wood on it as a clock.

Either way I really like them.

[Dr. Jon]

Are box chronometers watches or clocks?

The arguements are that they watches are they are fully portable and use spring power and spring regulation.

Many clock people regard Chelsea "clocks" as watches.

On the other hand there are carraige clocks and simple ones to my knowledge have always been considered clocks. To my knowledge no one has worn a box chronometer as a personal time piece. These factors suggest that they are clocks.

I also know some clock types who regard anything with wood on it as a clock.

Either way I really like them.

[Andy Dervan]

Hi Jon,

Chelsea would like to think of their products as clocks ala Chelsea Clock Co. not Chelsea Watch Co. Their products run 8+ days on a winding rather than slightly over one day as a watch.

Box chronometers and deck watches are considered clocks - you can't carry them around on your wrist or around your neck like you suggest.

However, pocket chronometers (highly accurate pocket watches) exist that supposedly have almost equivalent performance to box chronometers. They were used by mainly European military.

Andy Dervan

[D.H. Grace]

Jon and Andy,

I think part of the classification problem stems from the two timepiece descriptors most commonly used in the English language--watch and clock.

"Clock" derives from the French word for "bell". Timepieces that are able to announce the time using sound rather than sight all fall under the definition of "clock", regardless of escapement type, portability, etc. That's also why watches that strike the hour, and don't just repeat on demand, are called "clock watches".

Timepieces that are based on clock technology, but do not have the ability to strike the time are also referred to as clocks in common parlance. Hence, John Harrison's "sea clocks" H1 through H3 are referred to as clocks, because they're pendulum based and derived from his clock technology. Similarly, non-striking carriage clocks, even though some are small enough that you could wear them on your wrist, are called clocks because they were intended to tell time and are just simplified versions of their striking brethren. The same goes for Chelseas, even if they don't strike or have pendulums. They're still firmly in the clock category.

That said, people who are not terribly interested in fine timepieces, or the language, often use the word "clock" as a blanket term when it shouldn't be. Most old clock makers would shudder to hear astronomical regulators and other stationary precision timekeepers referred to as "clocks". The makers themselves were careful to distinguish between timekeepers and ordinary instruments that just told the time. That's one of the reasons it's not unusual to see the word "timekeeper" emblazoned on astro dials or early chronometer dials. It was a loud reminder that these instruments were different from ordinary timepieces--they were designed to "keep" time rather than tell it.

Box chronometers have very little in common with common clocks. Since H-4, their technological basis has been watch derived. The only difference between pocket chronometers and box chronometers is the way the watch-based movements are housed. There are box chronometers with tiny movements and pocket chronometers with 70 or 80 mm movements. The gimballed housing of the box chronometer usually produces the most stable rate, although the other mountings have advantages in certain environments. A pocket chronometer in a deck box mounting can perform better in situations where harmonic vibrations might cause a gimbal to rock. Similarly, pocket watch cases serve well in climates like the polar regions where body warmth helps alleviate extreme temperature fluctuations.

Like pendulum-based precision regulators, though, chronometers are designed to "keep" time rather than tell it. This distinguishes them from ordinary watches. Chronometers are not, I repeat NOT, accurate (despite what the NAWCC museum's website text might claim). They're precise. You can't just look at the hands on a box chronometer dial and instantly know what time it is in Greenwich, or anywhere else. On a good chronometer the hands might display a time that's inaccurate by hours. Even on the most accurate chronometer, to derive the time, you have to know the instrument's rate, the number of days it has run since it was rated, and then do the math. That's because precision is what counts if you're trying to "keep" the time. It's also why the best descriptive term for the box chronometer is "portable precision timekeeper".

Big auction houses, museums and the like are usually careful enough with the language to list chronometers as precision timekeepers. If forced to choose between watch or clock as the only classifications, though, boxed chronometers would generally fall under the former category and astro regulators under the latter.

At least that's the way I see it.

Regards,

David

[Dr. Jon]

Thanks for the thoughful and informative replies.

[Ralph]

....and then there are the German's. While in the process of buying a precision regulator (timepiece) from a German firm, the english correspondence kept referring to it as a watch. The shipping quote was remarkably low and it worried me that I was going to get something different than what I thought I was buying. I kept trying to clarify what I was buying (for a friend) and they kept assuring me that everything was fine and we were indeed talking about the same item.

Well, everything went smooth and I received the "watch" a few days later, air shipped, for extremely fair money....custom crated and all.

The uncrated "watch" stood proud, a full 6' tall.

Ralph

[Tom McIntyre]

David, I think everyone in the world except scientists has trouble with precision vs. accuracy. I know quite a few scientists who get confused regularly.

Precision also arises in the expression of a measurement and the common sophomore error of division leading to false precision with results expressed to 6 decimal places that are only really precise to the units.