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Thank you very much for your quick answer, Mr. Huxtable. It was very useful. 
You have deciphered my e-mail address well.

Please, can you send me your reply once more to my e-mail address? I haven't 
obtained it from the list - maybe the server was not accustomed to me in the 
first hours of my presence. The reaction of Jared Sherman reached me already.

And another request and probably more demanding one - you have mentioned in 
the past weeks that you had collected a list of printing errors in Cotter's 
"History of Nautical Astronomy", and you offered it to the list members. Can 
I ask for it, if it is not difficult for you? Thank you very much. In my 
opinion, Cotter's treatment of very popular Dunthorne's method for clearing 
L.D. isn't correct, among other things.

Upon second thought, I suppose that there must have been an important turning 
point in the history of relations of L.D. and chronometer - the introduction 
of the temperature corrections for the chronometr rates. Lecky speaks of them 
as of a rather new concept in his "Wrinkles" from 1881, so they might have 
been commonly introduced in 1870 or so. (I am waiting for Gould's book on the 
history of chronometer via interlibrary services.) After that, the 
chronometer time may have been correct within twelve seconds even after 
several months offshore without any check - provided that no mechanical 
failure took place. L.D. could only discover such potential failure then, not 
more.

But before, even the best chronometer in the best condition could deviate for 
one minute during one month of great temperature differences to the 
temperature, for which its standard rate had been established. After two 
months of deep-sea navigation, chronometer and L.D. became equivalent in 
their reliability.


Jan Kalivoda

   

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