On taking the chair, Mr. Sumner made the speech below, and then introduced Richard H. Dana, Jr., Esq., of Boston, a delegate to the Buffalo Convention, who reported what had been done there. He was followed by John A. Andrew, Esq., who moved a series of resolutions affirming the principles declared at Buffalo and ratifying the nominations. The reading of these was continually interrupted by applause. Mr. Sumner then introduced David Dudley Field, Esq., of New York, who insisted at length upon the prohibition of slavery in the Territories. Then came Rev. Joshua Leavitt, representing the Liberty Party, now dissolved in the Free-Soil Party. The meeting was singularly auspicious. FELLOW-CITIZENS, FRIENDS OF FREEDOM:-- Grateful for this cordial welcome, I must consider it offered, not to myself, but to the cause, whose humble representative I am. It is the cause, the good old cause of Freedom, so familiar to early echoes of this hall, which justly awakens your regards, irrespective of men. We are nothing; the cause is everything. And why, in this nineteenth century, are we assembled here in Faneuil Hall, to vow ourselves to Freedom? Because Freedom is now in danger. The principles of our fathers, of Washington, Franklin, and Jefferson, nay, the self-evident truths of the Declaration of Independence, are assailed. Our Constitution, which was the work of Freedom-loving men, which was watched by Freedom's champions, which, like the Ark of the Covenant, was upborne by the early patriarchs of our Israel, is now prostituted to the uses of Slavery. A body of men, whose principle of union was unknown to the authors of the Constitution, have seized the government, and caused it to be administered, not in the spirit of Freedom, but in the spirit of Slavery. This combination is known as the Slave Power.