See the presentation (. pdf File) Thursday January 12th 2006 at the time of the conference "Epistemology and history of sciences and technology in the training of the Masters" with the IUFM of Antony.

In 1672-1673, astronomer Richer was charged by the newly founded French Academy of Science with a scientific expedition. He was to go to a place close to the equator, in Guyana. In its first report to the Academy Richer wrote:
"One of the most considerable observations I made, is that the length of the seconds pendulum was shorter in Caïenne than in Paris"

This statement was a point of departure for the recreation of original Richer’s experiments. The re-enactments took place in the College Leon Gontran Damas of Cayenne and ENS-Lyon, during the festival of science in October 2004.

The students made a thorough study of the historical text of Richer’s mission and the accounts of the scientists implied in the experiments in France (Huygens, Picard and Cassini). However, there were some difficulties with the replication of the "pendulum of Richer". It has been therefore decided that another attempt will take place on Tuesday October 24, 2006 by high-school pupils in both Lyon and Cayenne, who will be working together through a videoconference facilities.

This event will have historical introduction: this will be based on explaining the advancement of Richer in Cayenne (scientific context of the end of the XVII century science, the history of scientific development in the field, instruments used and observations results). At the same time, we will cover our re-enactment of the experiment.

Moreover two days of continuous professional development training is proposed for the professors of physics, which will take place on Monday 23^rd and Tuesday 24^th October 2006 at the Academy of Lyon. This course will further examine the topics related to gravitation, the shape of the Earth and is planned in conjunction with the conference on Sciences of the Earth “Formaterre”.

A measurement of longitude by the method of eclipses of Jupiter’s satellites, (as suggested by Galileo, developed by Cassini, and certainly used by Richer) will take place simultaneously in France and in Cayenne (in January and June 2007).

The professors who participate in this project will measure the parallax of Mars at the time of its next opposition on December 24^th, 2007, just like Richer and Cassini once did. This aspect of the project can be further developed by the participating professors, particularly if they founded.

Translation: Snezana Lawrence
http://www.mathsisgoodforyou.com/