  The Pascal family moved residence frequently, for political and financial reasons. They transferred initially to Paris in November 1631, although Étienne was forced to return seven years later to his original home in what had meantime become Clermont-Ferrand, because he expressed public dissent about the crown's fiscal policies. France had declared war on Spain in 1635, and this intermittent campaign lasted for most of Blaise Pascal's life. The international and local political context in which Pascal lived, together with very public disputes between competing religious and theological traditions in which he participated, helped determine the issues to which he contributed philosophical comments in the 1640s and 1650s. For example, following the revolt of the Nu-Pieds in Normandy in July 1639, Pascal's father was awarded a new post as a tax collector in Rouen, to which he moved in 1639; his son, Blaise, followed in 1640. While still in Paris, he had written the short Essai pour les coniques (1640) and, despite his youth, had been introduced to the Mersenne circle by his father as a promising young mathematician. Later at Rouen he developed the first prototype of his calculating machine (1645), and began to experiment with mercury barometers. Pascal's introduction to barometric experiments occurred by chance when the royal engineer, Pierre Petit (1598–1667), passed through Rouen in September 1646 and informed both Pascals, father and son, about Evangelista Torricelli's experiments in Italy. Pascal performed experiments with mercury barometers initially in Rouen and Paris, and published Expériences nouvelles touchant la vide in 1647. Since he was too ill to do so himself, he arranged for his brother-in-law, Florin Périer, to conduct on his behalf one of the most famous experiments of the scientific revolution on the puy-de-Dôme, in the Auvergne.