The unexpected successes won by the young philosopher in a very short time in the realm of science, soon showed that his course had now been turned into the proper channel. Galileo’s father, who, almost crushed with the burden of his family, could with difficulty bear the expense of his son’s residence at the University, turned in his perplexity to the beneficence of the reigning Grand Duke, Ferdinand de’ Medici, with the request that, in consideration of the distinguished talents and scientific attainments of Galileo, he would grant him one of the forty free places founded for poor students at the University. But even then there were many who were envious of Galileo in consequence of his unusual abilities and his rejection of the traditional authority of Aristotle. They succeeded in inducing the Grand Duke to refuse poor Vincenzo’s petition, in consequence of which the young student had to leave the University, after four years’ residence, without taking the doctor’s degree.[17] In spite of these disappointments, Galileo was not deterred, on his return home, from continuing his independent researches into natural phenomena. The most important invention of those times, to which he was led by the works of Archimedes, too little regarded during the Middle Ages, was his hydrostatic scales, about the construction and use of which he wrote a treatise, called “La Bilancetta.” This, though afterwards circulated in manuscript copies among his followers and pupils, was not printed until after his death, in 1655.