Its tribal deity, the god of the mountain, the Puy de Dome, rechristened in Roman phrase Mercurius Dumias, was famous far beyond its territory.
In 1647 he published his Nouvelles experiences sur le vide, and in the next year the famous experiment with the barometer on the Puy de Dome was carried out for him by his brother-in-law Perier, and repeated on a smaller scale by himself at Paris, to which place by the end of 1647 he and his sister Jacqueline had removed, to be followed shortly by their father.
But the suspicions aroused by his conduct found further confirmation when he caused himself - or allowed himself - to be nominated bishop of Le Puy by Benedict XIII.
This experiment was made by himself in a tower at Paris, and was carried out on a grand scale under his instructions by his brother-in-law Florin Perier on the Puy de Dome in Auvergne.
The plateau type was most extensively developed during the formation of the Calciferous Sandstone; the puy type was of somewhat later date.
It contains many mountains volcanic in origin (Plomb du Cantal, Puy de Dome, Mont Dore), fertile valleys such as that of Limagne, vast pasturelands, and numerous medicinal springs.