thought and observation, and controversy has arisen as to the exact merits of each; but Pascal has himself so candidly explained5 how far he was indebted to his great Italian predecessors, and how far he made original experiments of his own, that both his relation to them and his own work stand clearly apparent.
It had been found by the engineers engaged in the construction of fountains for Cosmo dei Medici in Florence that they could not raise water in an ordinary pump more than thirty-two feet above the reservoir. The water, having reached this height, would rise no higher. Galileo was appealed to for a solution of the difficulty.6 Imbued with the ancient notion that Nature abhors a page 30vacuum, and that this was, as then prevalently believed, the explanation of the water following the elevation of the piston in the pump, the philosopher replied in effect that there