DEAR SIR,--It would give me pleasure to mingle with my fellow-citizens at Middleborough in pledges of earnest support to our candidates recently nominated at Chicago, but duties here will keep me away. Be assured, however, of the sympathy, which I offer more freely because I find in the Platform declarations full of glorious promise. Our victory will be worth having, only as it is a victory of principle; but such a victory I expect. Because I believe that our candidates hate the _five-headed_ Barbarism of Slavery, and will set their faces against all its irrational and unconstitutional pretensions, I am earnest for their success. Accept my thanks for the honor of your invitation, and believe me, dear Sir, Faithfully yours, CHARLES SUMNER. F. M. VAUGHAN, Esq., Secretary, &c., &c. REFUSAL TO COLORED PERSONS OF RIGHT OF PETITION. NOTES OF UNDELIVERED SPEECH IN THE SENATE, ON RESOLUTION REFUSING TO RECEIVE PETITION FROM CITIZENS OF MASSACHUSETTS OF AFRICAN DESCENT, JUNE 15, 1860. June 5, 1860, Mr. Sumner presented a petition of citizens of Massachusetts, of African descent, praying the Senate to suspend the labors of the Select Committee appointed to investigate the facts of the late invasion and seizure of public property at Harper’s Ferry, and that all persons now in custody under the proceedings of such Committee be discharged, which was duly referred to the Select Committee. * * * * * June 15, Mr. Mason submitted a report from the Committee, accompanied by the following resolution:-- “_Resolved_, That the paper purporting to be a petition from ‘citizens of the Commonwealth of Massachusetts, of African descent,’ presented to the Senate by Charles Sumner, a Senator of Massachusetts, on the 5th of June, instant, and on his motion referred to a Select Committee of the Senate, be returned by the Secretary to the Senator who presented it.” This resolution was never called up for consideration, but it stands on the Journal of the Senate in perpetual testimony of the assumption of the Slave Power and its tyrannical hardihood. Anticipating its discussion, Mr. Sumner prepared the notes of a speech upon it, which are here preserved precisely as sketched at the time. It is difficult to treat this proposition, proceeding from a Committee of the Senate, except as you would treat a direct proposition of Atheism. “The fool hath said in his heart, There is no God”; but it was only in his heart; the fool in Scripture did not openly declare it. Had he openly declared it, he would have been in a position hardly more offensive than your Committee.