Horological Meandering

nickd
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Thoughts

Hi Narsi,

I'm a bit confused about some of the points in the info you quote.  For example, I'm not at all sure that variations in gravity are a major, or even a minor, concern for wristwatches.  Given that movements like the Lemania 5100 are known to be able to pull many Gs, and that watches have been worn into space with no apparent timing problems, I don't see how it can be that much of a factor.  Gravity certainly is a problems for ultra-precision clocks, but we're talking of fractions of a seconds per year, not seconds per day, and it's due to a very specific effect - the pendulum rod being microscopically lengthened or shortened by changes in gravity.  The key point in clocks is that as they never move, and as the pendulum is pulled on by gravity, there's a very definite connection between the change in gravity and change in rate.  In a watch that's being worn, and hence moving all the time, I don't see an analagous constant physical change that would cause a different, stable rate.

I wonder if there are translation problems.  The sentence "Typically a chronometer certification certifies the deviation of the watch in various positions and temperature changes. " doesn't make sense to me.  The certificate gives absolute figures and average (mean) figures, and it rates these against a standard, so I don't know how "deviation" comes into it.

Similarly, the sentence "Thus it is not the deviation but the consistency of the rate of change or deviation that determines if a watch can be termed to be running accurately." strikes me as odd.  Consistency of rate of change of what?   You normally talk of rate of change of daily rate or similar, but I realy don't understand it in this context.

I think the final sentence is trying to say something like "The absolute rate is not important, but it's the consistency of the rate that determines if a watch can be said to be running accurately", and I'd have no problem with this statement.

Sorry to be nit-picking, but I found it very confusing.

nick