NavList:

Dear list members,
I think that of all (archeo)-navigation topics, chronometers were not
discussed
on this list in all detail.
I recently purchased one (a late Soviet one), and I have many
questions.

1. In the general books about chronometers (NOT the navigation books)
they say that it is not important that a chronometer shows "exact
time".
The important feature is the "constancy of rate". For example, if a
chronometer
shows 24 hours and 1 second for each 24 hours period, this is a good
chronometer,
because you can have an easy correction formula:
True time=(Chronometer time) minus (the number of days since the last
checkong) seconds.
My question: what was the normal practice in XIX and early XX century.
Did they routinely determine the daily rate and then used a linear
correction formula
True time=(chronometer time) plus (the daily rate) times (the number
of days since the last checking) plus constant?

Or they just tried to regulate a chronometer to have zero daily
deviation and then used
the time it shows as the true time? Somehow I cannot find the answer
in the navigation manuals
and even in Chauvenet.

2. Since I bought my chronometer, I put it on test, that is I wind it
regularly and check against
a good electronic watch. (The electronic watch I check every month
against GMT on the internet).
The experiment (which is running for about 1 month already) shows that
the chronometer is
slow by 1.4 seconds every day in the average, and if I add this
correction, the chronometer
time is accurate within 1 second most of the time. Is this a good
chronometer?

The factory certificate says that the maximal daily "going" has to be
at most 3.5 sec, and
this particular one showed 1.3 seconds on the factory test.

3. There was a funny story of purchasing this chronometer (from
Russia) which I can tell if there
is any interest:-)

Alex.

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