The Tour Saint-Jacques dominates Paris and offers an exceptional panorama, It also was the place of experimentations of Blaise Pascal.

Vestige of a church

Standing a few dozen meters from the banks of the Seine, and anchored in the heart of its personal square, the Tour Saint-Jacques dominates the capital from the top of its 62 meters and offers a view exceptional panorama. This other great Parisian lady remains unknown to Parisians, the kind of monument that we know by heart, without knowing much about it. Erected between 1509 and 1523, the tower is the only vestige of the Saint-Jacques-de-la-Boucherie church, built in the 16th century and destroyed in 1797, a sanctuary which was the meeting point and starting point for the pilgrimage of Saint -Jacques de Compostela. In 1648, Blaise Pascal wanted to carry out an experiment on gravity.

An experiment on gravity

At that time, it was openly admitted that one could not obtain a vacuum. However, Galileo had noticed that the fountain workers of Florence could not raise water above 10.33 meters. One of his students, Torricelli, pondered the question. He explained the phenomenon, using a tube, filled with mercury, giving birth to the barometer, in 1643. However, not much publicity was given to this discovery. Also, the experiment was repeated in Rouen in 1644.

A success for Blaise Pascal

Two years later, Pascal reproduced it using water and red wine in September 1648. At the same time, he asked his brother-in-law to do the same at the top of the Puy de Dôme, at the same time as him. On the strength of his success, he did it again in Saint Jacques, on October 8, 1648. Also, in memory of this experience, the restorer of the Tour Saint Jacques, Théodore Ballu, placed a statue representing Pascal. He entrusted to Mr. Cavelier, this great representation, which one can always see today while passing at the foot of the tower, at the level of the street of Rivoli