I have received your kind invitation to be present at Cleveland, on the 13th inst., to celebrate the anniversary of the great “Ordinance” which excluded slavery forever from, and secured freedom forever to the North-western Territory. If I could tell you how deeply I sympathize with you in this movement, and how much my soul desires, not merely to celebrate, but to hallow the event, you would then believe me when I say, that I have had a sharp struggle not to forego all considerations of business and of health, for the purpose of joining in your festival. I regard the Ordinance which redeemed a territory of more than _two hundred and sixty thousand square miles_, from the unspeakable sin and curse of slavery, and consecrated it to freedom, as one of the grandest moral events in the annals of mankind. Without that Ordinance, the Declaration of Independence itself, in its application to that vast and fertile region, would have been deprived of its power to confer blessing and prosperity upon it; and it is a fact never to be forgotten, that the original Declaration and the original Ordinance were both drawn up by the same great champion of human rights, whose hatred of slavery grew strong and deep by his personal knowledge of its wrongs and its calamities. Without the Ordinance, the Revolution itself, in its application to that territory, and the treaty of 1783, by which its ample domain was secured to the Union, would have been shorn of their glory, and robbed of their value. Without the Ordinance, the discovery of this Western continent, so far as that territory constitutes a part of it, would have given us no occasion to remember the name of Columbus with gratitude. Without the Ordinance, it would have been better, at the creation of the world, that all that part of it which now constitutes your five beautiful and flourishing states, with a residuum of space large enough for still another, had been left as a “Dead Sea,” whose bitter and poisonous waters would not have allowed a live thing to swim beneath its surface, nor to fly above it, nor a green thing to grow by its shores. And without the Ordinance, it is no irreverence to say, that even the omnipotent Spirit of God, working through natural laws, for human progress and human blessedness, would have met with bafflings and threatenings in its operations and influences for the redemption of the race. Accept, gentlemen, the assurance of my sympathy and regard. HORACE MANN. Messrs. J. C. VAUGHAN, } Committee. THOMAS BROWN, } LETTER ACCEPTING THE NOMINATION OF THE FREE SOIL CONVENTION FOR REPRESENTATIVE TO THE THIRTY-SECOND CONGRESS. WEST NEWTON, Oct. 24, 1850. HON. C. F. ADAMS;