After the celebration of the opening of the New York and Erie Railroad, noticed in our Record of last month, President FILLMORE returned to Washington by way of Rochester, Albany, New York, and Philadelphia. He reached the seat of Government on the 24th of May, after an absence of twelve days. Mr. WEBSTER remained behind for a few days, and delivered, at Buffalo, Syracuse, and Albany, a series of elaborate speeches, setting forth his views of the state of public affairs, and explaining and vindicating his course and principles. He expressed his entire and hearty concurrence in all the prominent measures adopted by the Administration. The question, as far as related to the North, was not one of Union or Disunion; but whether the Constitution should be so administered that all the members of the Confederacy could remain within it. He disclaimed, most emphatically all idea of concession; the South should not have a hair's-breadth of concession from him; but he would maintain, to the utmost of his power, and in the face of all danger, the rights, under the Constitution, of the South as well as of the North; "and God forsake me and my children, if I ever be found to falter in one or the other." He gave a sketch of the historical relations of slavery to the Constitution; and insisted that the meaning and intent of the clause providing for the return of fugitives from labor, was so plain and evident, that not an attorney could be found who could raise a doubt about it. It was assumed in many quarters, that if a colored man comes to the North, he comes as a freeman; but, according to the Constitution, if he comes as a fugitive from service or labor, he is not a freeman, and must be delivered up, upon claim of those who are entitled to his services. There was not a man who held office under the General or State Government who was not bound by solemn oath to support and carry out this clause of the Constitution. Mr. W. asserted most emphatically, that he was and ever had been opposed to the admission of new slave territory into the Union, believing that it was beyond the power and against the provisions of the Constitution. He would never consent that there should be one foot of slave-territory beyond what the old Thirteen States had at the time of the formation of the Union. He was not in Congress at the time of the acquisition of Louisiana and Florida. But when the project of the annexation of Texas was about to be brought forward, he had gone out of his way, in a speech at New York, in 1837, to denounce, in advance the annexation of Texas as slave territory to the United States. He then expressed the opinion that the people of the United States would not, and ought not to consent to bring this territory into the Union. But he had proved a false prophet. The State of New York consented to it, and the vote of her Senators decided the question. In Congress, before the final consummation of the deed, he fought against