This system gave to the planters far greater leisure than they had possessed in the earlier part of the colony's existence, and they made use of this leisure to cultivate their minds and to diversify their interests. It is only in this way that we can fully explain why the aristocrat surrounded himself with a large library, indulged in the delicate art of music, beautified his home with handsome paintings, and revelled in the dance, in races or the fox hunt. This too explains why there grew up amid the plantations that series of political philosophers that proved so invaluable to the colonies in the hour of need. Jefferson, Henry, Madison, Marshall, Randolph, would never have been able to give birth to the thoughts that made them famous had they been tied down to the old practical life of the planters of early days. The old instinct had been distinctly lacking in the philosophical spirit. As Hugh Jones says, the planters were not given to prying into the depths of things, but were "ripe" for the management of their affairs. With the greater leisure of the 18th century this spirit changed entirely, and we find an inclination among the aristocrats to go to the bottom of every matter that came to their attention. Thus John Randolph was not only a practical statesman and a great orator, he was a profound thinker; although Thomas Jefferson was twice president of the United States, and was the author of the Declaration of Independence, it is as the originator of a political creed that he has the best claim to fame; John Marshall, amid the exacting duties of the Supreme Court, found time for the study of philosophy. In men less noted was the same spirit. Thus Robert Carter of Nomini Hall in his love for music, did not content himself with acquiring the ability to perform on various instruments, but pried into the depths of the art, studying carefully the theory of thorough bass.[134] He himself invented an appliance for tuning harpsichords.[135] This gentleman was also fond of the study of law, while he and his wife often read philosophy together.[136] Fithian speaks of him as a good scholar, even in classical learning, and a remarkable one in English grammar. Frequently the gentlemen of this period spent much time in the study of such matters as astronomy, the ancient languages, rhetoric, history, etc.