> "Harry" <harald.vanlin...@epfl.ch> schrieb im Newsbeitrag
> news:43328457$1@epflnews.epfl.ch...

> > "Martin Ouwehand" <see....@end.of.post.ch> wrote in message
> > news:43313e74$1@epflnews.epfl.ch...
> >> In article <1126626847.877636.161...@g43g2000cwa.googlegroups.com>,
> >>  "Juan R." <juanrgonzal...@canonicalscience.com> writes:

> >> Another example: "the Lorentz transformation replaces the real electron
> >> in motion by an ideal electron at rest."

> It seems to me like a debate about words: Einstein also uses "ruhendes
> System" (= system at rest) because of didactic reasons, and Poincaré used
> ether because of didactic reasons and because he has known, that this is
> allowed.

> >> It is definitely not the same as
> >> Einstein's. For instance in his 1908 article (available from
> >> http://www.soso.ch/wissen/hist/SRT/srt.htm -- BTW thank you Homo Lykos
> >> for the link !),

> > BTW, also that german link reminds us of the fact that Poincare spoke
> > about real clocks and not just about mathematical manipulations:
> > "Im zweiten Büchlein findet man als Kapitel 2 wieder seine Arbeit von
> > 1898 über die Zeitmessung, wo er das Konzept der Relativität der
> > Gleichzeitigkeit erstmals deutlich formuliert hat"

> >> I understand from his arguments around pages 565-566
> >> that he uses the following transformation:

> >> x' = (x - v * t) / sqrt(1 - v^2/c^2)        (Lorentz contraction)
> >>         t' = t - (v * x) / (c^2 - v^2)              ("local time")

> >> (x', t') is what is actually measured by an observer in motion with
> >> respect to the ether, (x, t) are the coordinates in the ether frame
> >> (beware that in his formula for the local time, he expresses x in term
of
> >> x', resulting in a slightly different formula). With the help of this
> >> transformation, he is able to explain the null result of the Michelson
> >> experience: the time of travel of a light pulse along a given distance
> >> doesn't depend on the direction. But the transformation rule for the
> >> speed of light (last equation on page 566 -- BTW there is a misprint: t
> >> should be replaced by tau) is:

> >> c' = c * sqrt(1 - v^2/c^2)

> Such a nonsense you don't find on page 566.

> My interpretation (for the present) of this (strange) page 566:

> 1. This paper is written in a popular manner (almost no equations and
> no real proofs, he don't makes use of setting V = 1 as in his papers of
> 1905)

> 2. His "popular proof" of Michelson/Morley seems to me with respect to his
> own theory of 1905 incorrect.

> Especially strange for me:

> " Supposons que la différence entre le temps vrai et le temp local en un
> point quelconque soit égale à l'abscisse de ce point multipliée par la
> constante: e/(V sqrt(1-e^2)) "

> Poincaré gives no explanation for this (and speaks only of supposons(=we
> suppose)) and I - at least in this moment - can't understand it.

> 3. If it is really only a (strange) error - as I believe now - it's not
> possible to derive any conclusions.

> >> which doesn't respect the principle of relativity (by measuring the
speed
> >> of light in different frames, it's possible to tell which is moving
> >> fastest whith respect to the ether.)

> > - I did not see the misprint (duration= t, apparent duration= tau), but
> > the last AB on the copy certainly was AB'.

> No

> >> do you know of an earlier reference where
> >> Poincaré actually mentions it *in words* and says something like "Hey !
> >> motion has an influence on the *rate* of clocks !" ?

> > I also don't remember having seen that he expressed that in words.
> > Maybe Einstein was the first to verbally point out that the effect on
> > clocks implies that "moving clocks" "go more slowly"?

> I think too, that Einsteins (popular) explanations of all these things
were
> clearer and more specific then the explanations of Poincaré; but from
> Poincaré Einstein had first learned these more philosophical ideas about
> space and time. Now I copy older citations of Poincaré in this context:

> The strong general statement of 1898 in La Mesure du Temps:

> " La simultanéité de deux événements, ou l'ordre de leur succession,
> l'égalité de deux durées, doivent être définies de telle sorte que
l`énoncé
> des lois naturelles soit aussi simple que possible. "

> More specifically 1904 in St. Louis (Bull. des Sciences Mathématiques,
> deuxième Série, tomé XXVIII):

> " .... Pour un observateur, entraîné lui-même dans une translation dont il
> ne se doute pas, aucune vitesse apparente ne pourrait non plus dépasser
> celle de la lumière; et ce serait là une contradiction, si l'on ne se
> rappelait que cet observateur ne se servirait pas des mêmes horloges qu'un
> observateur fixe, mais bien d'horloges marquant le "temps local". "