SIR--I have the honor to acknowledge the receipt of your note of the 12th instant, conveying to me the information of your appointment (in connection with colleagues expected soon to arrive), by a Convention of the colored people of the United States and the Canadas, 'Commissioners,' under the name of 'The Niger Valley Exploring Party'; and of your arrival near this Government. You have also been pleased to signify, that you will duly appreciate any aid, oral, documentary or in the form of an official Commissioner this Government may feel disposed to afford you, in facilitation of the enterprise. In reply, I have to express my deep regret, that the receipt of your very interesting note is on the very eve of my leaving this city on an official visit to the leeward counties, which will, for the present, deprive me of the pleasure I had anticipated of an interview with you on the very interesting and highly important objects of your mission. The Hon. John N. Lewis, Secretary of State, with whom I will converse on the subject matter of your note before leaving, will be pleased to grant you an audience; and will, with pleasure, meet your wishes, so far as he can consistently. Please be reassured of the deep interest I feel in your very laudable enterprise; and that, if it were not for very important despatches received last week from the county of Maryland, which make it absolutely necessary that I should delay no time in reaching there, I would defer my departure a couple of days for the express purpose of consultation with you in person. I have the honor to be most respectfully, Your very obedient servant, To M. R. Delany, Esq., &c. STEPHEN A. BENSON * * * * * Monrovia, July 13, 1859 Martin R. Delany, Esq.: DEAR SIR--The undersigned, citizens of the city of Monrovia, having long heard of you and your efforts in the United States to elevate our down-trodden race, though those efforts were not infrequently directed against Liberia, are glad to welcome you, in behalf of the community to these shores; recognizing, as they do in you, an ardent and devoted lover of the African race, and an industrious agent in promoting their interests. And they take this opportunity of expressing to you their most cordial sympathy with the enterprise which has brought you to these shores, sincerely praying that your endeavors may be crowned with complete success. The undersigned, further, in the name and behalf of the members of this community, respectfully request that you would favor the citizens with a lecture to-morrow evening, or on any other evening you may choose to appoint, at half-past seven o'clock, on any subject you may be pleased to select.