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From: Frank Reed (no email)
Date: Wed Jan 07 2004 - 04:50:20 EST
A week ago, Trevor K, you wrote:
"No Frank, that was not remotely clear."
Well, I do apologize. I must say that I accept it as *axiomatic* that it
takes two to have a misunderstanding, so some of this was my fault. I really
thought I was very clear at the outset that I was talking about the lag between
Spring Tides and New Moon/Full Moon.
You added:
"which any reasonable person would take to mean that what you intended by
"phase lag" was _not_ the same thing as the lag between New or Full Moon and the
date of highest spring tides. It is not a matter of my reading of your posting
but one of your posting itself being, at best, misleading."
But Trevor, you understood what I was talking about a few days earlier. I
still can't see how things went so badly wrong by Christmas Eve.
You added [for brevity, I'm quoting only the concluding comment]:
"That is not impossible. It might be a chance consequence of the shapes of
the marine basins around northwest Europe. But the odds of it happening must be
incredibly small."
Maybe, but I don't see it. There are quite a few so-called "phase
inequalties" which cover wide regions (wide regions with "full circle" variations in the
actual tide phase numbers). I don't understand what you find odd about them
and the fact that they exist.
You also wrote:
"I understand, Frank, that you have been caught posting an elementary error
and are now unwilling to accept responsibility."
No, TK. I did not post an 'elementary error'.
And you added:
"You did not write that "early navigational manuals claim" or that "Bowditch
thought". You posted that "In western Europe, the tide "wave" progresses up
the coast". That is, quite simply, false."
Yikes. No, it isn't. The tide in western Europe DOES progress up the coast.
It was one of the false leads in early tidal analysis (very naturally based on
European tides) that caused some long-lasting confusion with respect to global
tides. There are quite a few references to this in Cartwright's "Tides: A
Scientific History". Checking just now, the first reference to this was from
Bacon, of all people, and it was still a common description in the 19th century.
This "sea lore" stuff has had a continuing conservative impact on mariners for
generations.
Further along you wrote:
"I'll accept that, in this case, your words could be interpreted as meaning
"The early hints from Laplace were thought to explain differences along an
idealized rectangular east-west channel such as the English Channel" (though I'm
not sure that even someone in Laplace's day would have been so misguided as to
think that). But I doubt that I was alone in reading your words as meaning
"The early hints from Laplace can explain differences along an idealized
rectangular east-west channel such as the English Channel"."
This raises a more general issue. WE ONLY EXCHANGE WORDS HERE. I put this in
caps because it really IS a big deal. If you interpolate between other
people's words, you are adding meaning that is not present. Your specific "reading"
of my words does matter, since this is the essence of communication. But if you
insert words that I did not write, your "reading" may have more to do with
you than with me.
You asked:
"You had, after all, been invoking the real tides of the Channel and your
supposition that Bowditch had learnt from accounts of the real tides of the area.
Why invoke Laplace's theoretical treatment unless you supposed that it had
some connection with observed tidal phenomena?"
As I already noted, *I* did not "invoke Laplace's theoretical treatment".
George Huxtable invoked Laplace's theoretical treatment (and, in retrospect,
probably because of a sentence in Cartwright, but I can't be sure). To repeat, it
was not me who brought it up so asking why I invoked this treatment just
doesn't seem relevant.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
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