Giovanni Battista Baliani

Giovanni Battista Baliani, born in Genoa and living from 1582 to 1666, was an Italian mathematician, physicist and astronomer, governor of Savona in 1647 to 1649 and captain of the archers of the Republic of Genoa. For some twenty-five years he corresponded with Galileo about the most innovative scientific theories and experiments of the time. On 27 July 1630 he wrote to Galileo about a siphon led over a hill about 21 metres high that failed to work, the water in its limb sinking to about 10 metres above the reservoir, which Galileo explained by the power of a vacuum. At Savona he repeated Galileo's Tower of Pisa experiment with more precise measurements that showed the effect of air resistance, and he showed the heat generated by a pot of water rotated at high speed. His main work is De motu naturali gravium.