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Re: cathode rays - historical question



Mais oui.
On Sun, 6 Apr 2003, Bernard Cleyet wrote:

You also have "played with" the paddle wheel in the beam?

bc

Jack Uretsky wrote:

Hi all-
I quote excerpts from Richtmeyer and Kinnard, "Introduction to
Modeern Physics" (McGraw-Hill 1947) p.80:
"Previous to 1897, many studies had been made ot that beautiful
phenomena, the discharge of electricity through rarified gases...The
"something" which, under these conditions, seems to proceed from the
cathode and to cause the phosphorescene of the glass was early called
'cathode rays'...Finally, in 1895, Perrin caught the rays in an insulated
chamber connected to an electroscope and proved that they carried negative
charge."
It is most unlikely that a wave interpretation would have been
given to cathode ray phenomena because the electron beam is not
coherent, and therefore would not display diffraction or interference
patterns when, e.g., passed through a slit. A popular demonstration in
the thirties, in fact, was to place objects in the beam (such as crosses
or other shapes) and show the sharp images at the downstream end of the
beam. Many of your labs still have this equipment (I played with some at
College of DuPage, Illinois) about a decade ago.
Regards,
Jack

On Sun, 6 Apr 2003, Mark Sylvester wrote:

The debate in the latter part of the 19th century about the nature of
cathode rays, leading to J.J. Thompsons discovery of the electron: was it
primarily a wave vs particle question, or was the issue whether the
negative charge came attached to discrete particles as opposed to a
continuous fluid (bearing in mind that the atomic theory was not fully
accepted by the physics community in that period), or is there essentially
no distinction between the concepts of waves and continuous fluid (in that
anything not a particle had to be wavelike)?

Mark



Mark Sylvester
UWCAd
Duino Trieste Italy


--
"What did Barrow's lectures contain? Bourbaki writes with some
scorn that in his book in a hundred pages of the text there are about 180
drawings. (Concerning Bourbaki's books it can be said that in a thousand
pages there is not one drawing, and it is not at all clear which is
worse.)"
V. I. Arnol'd in
Huygens & Barrow, Newton & Hooke


--
"What did Barrow's lectures contain? Bourbaki writes with some
scorn that in his book in a hundred pages of the text there are about 180
drawings. (Concerning Bourbaki's books it can be said that in a thousand
pages there is not one drawing, and it is not at all clear which is
worse.)"
V. I. Arnol'd in
Huygens & Barrow, Newton & Hooke