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One small, additional note:  By the last quarter of the 19th century,
"railroad watches" were universally carried by American railroad
conductors and engineers (and as early as the 1850s on some railroads).
  These were essentially chronometer- accuracy (the standard was
actually 30 seconds per week) pocket watches.  For them to be
inexpensive enough that a railroad could require a an engineer or
conductor to own one at his own expense required the creation of an
American precision- instrument manufacturing infrastructure (from the
late 19th century onward, watches were required to be of American
manufacture although the earliest ones (ca 1850) were of British
manufacture).  Cost, according to one source, was about $25 (a LOT less
than 500 pounds sterling!).   A 1911 Scientific American advertisement
by the Waltham Watch Company mentions that Shackelton and Perry both
carried their railroad watches.

Lu Abel


Frank Reed wrote:
> Jim, you wrote:
> "One book I read of late  regarding chronometers initially after Harrison's
> time commented that a  chronometer would cost about 500 pounds sterling, a
> sizable sum compared to a  ship at about 1500. So, chronometers were
> expensive.Then you need at least 3 if  you want a reasonably simple way to check how
> consistent the rates are holding,  so more expense."
>
> Just as an incidental comment here, there were other  methods of proving your
> chronometer's accuracy, even assuming you didn't do  lunars and couldn't
> afford multiple chronometers. Ships almost always traded  longitudes when they met
> on the high seas. Also, there are numerous small  islands that can serve as
> longitude checks (assuming we are late enough in the  19th century that plotted
> positions can be trusted).
>
> And you  asked:
> "So, that is a long winded approach to getting to the question. What  was the
> experience with chronometers like for the average seafaring navigator  when
> mechanical chronometers were the order of the day?"
>
> In America, the  dividing line is around 1835 [based on the evidence I have
> seen so far.  additional evidence might convince me to shift this date but I
> very much doubt  the shift would be larger than ten years in either direction].
> Before this date,  most vessels got their longitude by dead reckoning (not
> just a rote calculation,  but also including other factors) and their latitude by
> Noon Sun. On a long  voyage, the reckoning might be checked a few times every
> two weeks by lunars,  but the DR was the "principal" longitude, and
> navigators took it very seriously.  After about 1835, a majority of American vessels
> were starting to carry  chronometers. In whaling logbooks from the early 1840s,
> it is not uncommon to  see references to two chronometers being carried. They
> still used lunars in the  era, taking them for a few days in a row every two
> weeks as a check on the  chronometer-based longitude. By 1855 or so, lunars
> were essentially history, and  chronometers were considered completey reliable
> for practical use. As I have  mentioned previously on this list, there was
> apparently no "lunars era" when  lunars were the principal method of getting
> longitude. They were always a check,  and a very valuable one, on the primary
> method, whether it was dead reckoning or  longitude by chronometer.
>
> In Britain, and in particular in the Royal  Navy, subtract 25 to 30 years
> from the dates above. For a specific case, one  "Lt. Ashe" writing in 1849 to the
> Royal Astronomical Society noted that he had  seen only a single instance of
> lunars being used to check chronometers in twenty  years at sea. Chronometers
> were not only widely available in the Royal Navy but  widely trusted by 1830.
> By contrast, British ocean-going merchant vessels seem  to have been closer to
> the American schedule.
>
> You also wrote:
> "Slocum  for example opted for an old tin clock instead of his chronometer
> and gives me  the impression that on those occasions that he did use celestial
> navigation that  it was almost as if he were checking his celestial navigation
> against his dead  reckoning as opposed to the other way round. He was always
> confident that he new  where he was and how to approach those various
> landfalls. He didn't need a fancy  expensive chronometer to get by although he was
> clearly as familiar with  celestial navigation as I would assume most navigators
> would be at that time. I  get the impression that sailors of the day were more
> tuned in to all the  elements affecting dead reckoning and relied on it
> heavily which may be a bigger  reason for the slow acceptance of the LOP."
>
> Yes, that's a good point.  Dead reckoning was far more popular and more
> successful than many modern  navigation histories (mostly anecdotal histories)
> would lead us to believe. And  navigators believed in their dead reckoning. Even
> in the 1850s, I have seen  examples of commercial vessels sailing to Java using
> nothing but dead reckoning  for longitude. As for Slocum, he had an
> advantage. He could choose his season  and his timing. As Slocum proved, you can sail
> around the entire world using  nothing but latitude by Noon Sun and dead
> reckoning longitude. Of course, if you  have to do that every day and you have a
> cargo to deliver on schedule, your luck  will eventually run out.
>
> -FER
> 42.0N 87.7W, or 41.4N  72.1W.
> www.HistoricalAtlas.com/lunars
>
>

   

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