In 1837 he visited Europe for purposes of travel and general improvement, and remained there for three years, returning in 1840. As the result of this sojourn, he added to his previous classical and legal knowledge an extensive and accurate acquaintance with the leading languages and literature of modern Europe. Possessed of a memory remarkable for its extent and accuracy, all these varied treasures were arranged in his mind where they could be found at a moment's notice. We have heard of his being present once at a dinner, among the Cambridge _élite_, when Longfellow repeated some French verses, which he said had struck him by their euphony and elegance, but to which he could not at the moment assign the name of the author. Sumner immediately rose from the table, took down a volume of Voltaire, and without a moment's hesitation turned to the passage. He has sometimes been accused of a sort of pedantry in the frequent use of classical and historical illustration in his speeches, but the occurrence of these has been the result of a familiarity which made their use to him the most natural and involuntary thing in the world. In the outset of Sumner's career it was sometimes said of him that he was a brilliant theorizer, but that he would never be a practical politician. His mind, indeed, belongs to that class whose enthusiasms are more for ideas and principles than for men. He had the capacity of loving the absolute right, abstracted from its practical uses. There was a tendency in his mind to seek ideal perfection and completeness. In study, his standard was that of the most finished scholarship; in politics and the general conduct of life it was that of the severest models of the antique, elevated and refined by Christianity. He returned to his native city at a time when the intention in good faith to be an ideal patriot and Christian, was in the general estimation of good society, a mark of a want of the practical faculties. The Whig party, in whose ranks, by birth and tradition, he belonged, looked upon him as the son of their right hand; though they shook their heads gently at what seemed to them the very young and innocent zeal with which he began applying the weights and measures of celestial regions to affairs where, it was generally conceded, it would be fatal to use them.