"It was a speech which, for beauty, eloquence, and convincing argument, I never heard equalled. With the utmost candor, with a power of argument not to be answered, with an array of facts which cannot be met, he examined the position occupied by Cass and Taylor. Refraining from all abuse, on the contrary dealing out praise where praise is due, he yet showed most conclusively that on the great question, the only question of importance now in issue, neither of these candidates could be trusted. He then spoke in a most beautiful manner of our candidate, Martin Van Buren, and his position. Extenuating nothing in his former action or opinion, he spoke of him _as he now is_, the true exponent of the glorious principles of the Buffalo Platform, which he called the Second Declaration of Independence. Mr. Sumner spoke for three hours, and to the close the hall was crowded. The bitterest opponents speak in the highest terms of the speech and the meeting." Another hearer at Amherst, writing in another newspaper, is equally enthusiastic "For three hours the multitude was swayed to and fro by his resistless eloquence. No description can do justice to the address. Its framework was logic and high moral principle, ornamented with refined and classical allusions and glowing images. Through the whole he was interrupted by long and hearty cheers. Toward the close he expressed a fear that he was detaining his audience too long (the clock was then striking midnight) but he was answered by cries from all parts of the house, 'Oh, no! go on! go on! talk all night!'" This introduction may explain what ensued. Mr. Sumner was nominated for Congress, and, under the circumstances, did not feel authorized to decline. Earnestly urging others to active support of the cause, he could not refuse the post assigned to himself. His letter accepting the nomination, after giving reasons for the step, proceeds to consider at some length the philosophy of parties and the necessity for the new organization in which he was enlisted. The nomination was communicated to him in a letter, which is given below, with his answer. The result will appear in the sequel. "BOSTON, October 23, 1848. "CHARLES SUMNER, ESQ. "DEAR SIR,--At a meeting of the Ward, County, and District Convention of the Free-Soil Party of Suffolk, held on Thursday last, it being proposed to go into a nomination of candidate for Representative to Congress, and nominations being called for, your name, and yours only, was placed upon the list.