Mr. Rogers, the President of the Young Men’s Republican Union, nominated for chairman of the meeting Hon. Abijah Mann, Jr., which nomination was unanimously accepted. Mr. Mann, on taking the chair, said that they had now to listen to the voice of one who had stood up manfully for freedom of speech, not only against open foes, but even against the opposition of some of his colleagues. [_Applause._] He was here to-night to maintain this same right to free speech, and to express his views of the political condition of the country. It gave him pleasure to introduce to the audience Hon. Charles Sumner, of Massachusetts. Mr. Sumner, on taking the stand, was again greeted with loud and prolonged cheers. After tendering acknowledgments for the generous and cordial reception, and regretting his inability to express all he felt, he proceeded with his speech, which was thus described by the _Evening Post_:-- “Mr. Sumner was as happy in the manner as he was forcible in the matter of his speech. His commanding person, his distinct utterance, and his graceful elocution combined with the eloquence of his words in keeping the immense auditory to their seats for two hours, without a movement, and almost without a breath, save when the applause broke forth. It is the first time that Mr. Sumner has spoken in public since he was laid low in the Senate House, and New York, by this grand demonstration, has shown its eagerness to welcome him to the field of so many former triumphs.” In this speech Mr. Sumner sought to popularize his argument in the Senate on the Barbarism of Slavery, with an application to the Presidential election, and at the same time to reassert the positions he had there taken. Its influence was increased by the circulation it enjoyed. Besides the _Tribune_, _Times_, _Herald_, and _World_, which printed it in full, there was a pamphlet edition of more than fifty thousand copies circulated by the Young Men’s Republican Union. The Secretary of the Republican Central Committee of California wrote, that this Committee, after publishing a large edition of the “Barbarism of Slavery,” published ten thousand copies of the New York speech, which was “read with that attention which the subject elucidated by you readily commands.” Among letters with regard to it, two are preserved as friendly voices. Hon. W. H. Seward wrote from Auburn:-- “Your speech, in every part, is noble and great. Even you never spoke so well.” Another friend, who had not agreed with Mr. Sumner at an earlier period, George Livermore, the intelligent merchant of Boston, devoted to books as well as business, being in New York at the time, heard the speech, and, in a letter dated at the Fifth Avenue Hotel, wrote:--