I would like a detailed description of the apparatus used by Marie
Alfred Cornu to measure the speed of light.  His apparatus is an
improvement to one by Fizeau.  The nature of these improvements is of
interest to me.

The description should be detailed enough to enable a repetition of
the experiment.  The distances between components in the actual
experiment is also required.  The description should also either
contain a diagram, or enough detail so that an artist could render
one.

The ideal answer would be an English translation of Cornu's
publication detailing the experiment, including any diagrams.

DETAIL:

The first successful measurement of the speed of light using an
earthbound apparatus was carried out by Hippolyte Fizeau in 1849.
Fizeau's experiment was conceptually similar to those proposed by
Beeckman and Galileo. A beam of light was directed at a mirror several
thousand metres away. On the way from the source to the mirror, the
beam passed through a rotating cog wheel. At a certain rate of
rotation, the beam could pass through one gap on the way out and
another on the way back. But at slightly higher or lower rates, the
beam would strike a tooth and not pass through the wheel. Knowing the
distance to the mirror, the number of teeth on the wheel, and the rate
of rotation, the speed of light could be calculated. Fizeau reported
the speed of light as 313,000 kilometres per second. Fizeau's method
was later refined by Marie Alfred Cornu (1872) and Joseph Perrotin
(1900).

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Clarification of Question by hagaba-ga on 13 Mar 2005 02:05 PST

Please include bibliographical references used in compiling the answer.

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Request for Question Clarification by leli-ga on 13 Mar 2005 08:24 PST

Dear hagaba

Good news and bad news: I've found detailed drawings attached to 300
pages of Cornu's report of his experiment, but everything's in French,
and references to the diagrams are scattered within the text.

Would you be happy with an answer referring you to all this?

I realise you were hoping this would be available in English, but
unfortunately there is far too much text for me to offer a
translation. I could certainly help with the words on the drawing of
the site of the experiment. Indeed I would do more if I knew how to
pick out an excerpt of particular interest to you.

By the way, the mechanical drawings of the apparatus are unlabelled,
except for letters which show when the same item appears from a
different perspective.

Please let me know if you'd like an answer showing you how to access
this material online.

Thanks - Leli