in] of the New Physics. 65 



observations on the heavens, but also his important physical 

 work, Be vi percussionis. But what he set his mind chiefly to 

 do was to write a treatise on animal motion, De motu animalium, 

 embodying the results of the anatomical and physiological 

 inquiries in which he had been so long engaged, and to the 

 prosecution of which he had so fruitfully stimulated others. 

 Although the work was not to see the light for many years, 

 much of it apparently was written before he left Pisa. 



For he did leave Pisa. It seems strange that he should 

 desire to leave such a centre of light to live once more in an 

 out of the way and provincial seat of learning. He pleaded as 

 his reasons the ungenial climate of Pisa and the desire for 

 more leisure and quiet ; others thought it was his inconstant 

 temper and his repeated quarrels with his colleagues that led 

 him, in 1668, after twelve years' stay at Pisa to accept an 

 invitation to return to his old University at Messina. Here if 

 he had more leisure, his intellectual activity at least in spite of 

 his increasing years shewed no signs of being on the wane. 

 He published his important treatise on ' The natural move- 

 ments depending on gravity,' he investigated an eruption of 

 Etna, he busied himself in literary and antiquarian studies, 

 and all the while he continued working on what he felt to be 

 his great effort, the treatise on animal motion. 



In 1674, being concerned, or being suspected of being 

 concerned, in a political conspiracy to free Sicily from the rule 

 of Spain, he left Messina for the last time and fled an exile to 

 Rome. There was at that time living in Rome that remarkable, 

 I ought perhaps to say notorious woman Christina (daughter of 

 Gustavus Adolphus of Sweden), who after bearing the burdens 

 of the crown for ten years (for at her father's death in 1644 she 

 succeeded to the throne) threw them on one side in 1654, in 

 order that, free from political cares, she might devote herself to 

 the charms of travel and of intellectual culture, and to other 

 pleasures of private life. She, playing the part of Lady 

 Bountiful in science, held a little academy of her own, and 

 when Borelli, a needy, or well-nigh needy exile arrived at Rome, 

 she took him under her protection. He earned the assistance 

 which she gave him by acting as her physician and also by 

 f. l. 5 



