THE following Sermon was preached on Sunday evening, May 26, 1850, before a large assembly of intelligent and respectable citizens of Charleston, at the dedication of a Church erected for the religious instruction of the Negroes. This building has been put up under the supervision of the Second Presbyterian Church. The congregation worshipping in it are under the ecclesiastical watch and control of the Session of that Church, into which will be received all those who may become Church members. There is, therefore, no separate ecclesiastical organization of this congregation. The Rev. JOHN B. ADGER is their Minister, and his successors will, from time to time, be appointed by the Session of the Second Church and by the Presbytery of Charleston. This commodious edifice is in the Gothic style—a model of neatness and simplicity. Its shape being that of a capital T, the transepts or wings are appropriated to the use of white persons and are entered by separate doors. The cost of this Church, including the lot and a small building in the rear, for Sunday School purposes, has been about $7,700. A balance of about $1,700 remained due at the dedication, but since that time it has been all paid, and the undertaking stands a pleasing monument of the Christian zeal of our community for the sound and thorough religious training of their slaves.