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I certainly didn't intend to argue the performance of a marine
chronometer against a railroad watch from almost a century earlier.  I
was merely responding to a comment that a professional mariner owned a
railroad watch and "swore by it" with a specification for such a
watch.   Thanks for taking the time to do a comparison of specifications.

Lu

Alexandre E Eremenko wrote:
> Dear Lu,
>
> This specification does not tell us much on comparison
> of railroad watches with chronometers.
> Let us compare the essential parameters.
> (I use the certificate of a Soviet chronometer of
> "Class II" made in 1980-s.
>
>
>> */American made 18 or 16 size /* (Soviet made)
>> /*Fitted with 17 or more jewels [21 was most common] (21)
>> /*Temperature compensated*/      (Yes)
>> /*Adjusted to 5 positions*/  (Jimbals. No need to adjust)
>> /*Lever Set*/                (No setting)
>> /*Timed to +/- 30 sec/week*/ (3.5 sec per day)
>> /* Plain white dial *//*having:*/   (Yes)
>> /*Black Arabic numerals*/           (Yes)
>> /*Each minute delineated*/ (Yes, and each second).
>>
>
> Additional parameters in specification:
> average deviation of daily rate: 0.35 sec.
> rate recovery:                    2 sec.
> maximal variation of the daily rate: 2.3 sec.
> secondary error of compensation:   1.2 sec.
>
> Let me explain these parameters.
> Chronometers were tested for 5
> consecutive periods of 5 days each,
> each period under constant temperature, and the
> temperatures were: 36, 20, 4, 20, 36 (Celsius).
> The rate deviation was recorded for every day.
> Now it is clear what the average rate deviation is,
> just the average of these 25 numbers.
> Rate recovery is the average rate on the fifth period
> minus average rate of the first period (they are at the
> same temperature).
> Maximal variation is the maximal difference of rates
> in two consecutive days.
> And "secondary error in compensation" is the
> average rate at 36 and at 4 degrees, minus the
> average rate at 20 degrees.
> (I would call this last quantity "non-linearity of
> the temperature compensation").
>
> Alex.
>
> P.S. I don't know how to reproduce this testing at home.
> To let it run 5 days in a refrigerator? :-)
>
>
> >
>

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