SIR,--It is my duty to communicate to you a piece of information, although I cannot say I have confidence in it myself. A French gentleman, one of the refugees from St. Domingo, informs me that two Frenchmen, from St. Domingo also, of the names of Castaing and La Chaise, are about setting out from this place for Charleston, with a design to excite an insurrection among the negroes. He says that this is in execution of a general plan, formed by the Brissotine party at Paris, the first branch of which has been carried into execution at St. Domingo. My informant is a person with whom I am well acquainted, of good sense, discretion and truth, and certainly believes this himself. I inquired of him the channel of his information. He told me it was one which had given them many pre-admonitions in St. Domingo, and which had never been found to be mistaken. He explained it to me; but I could by no means consider it as a channel meriting reliance; and when I questioned him what could be the impulse of these men, what their authority, what their means of execution, and what they could expect in result; he answered with conjectures which were far from sufficient to strengthen the fact. However, were anything to happen, I should deem myself inexcusable not to have made the communication. Your judgment will decide whether injury might not be done by making the suggestion public, or whether it ought to have any other effect than to excite attention to these two persons, should they come into South Carolina. Castaing is described as a small dark mulatto, and La Chaise as a Quarteron, of a tall fine figure. I have the honor to be, with great respect, your Excellency's most obedient, and most humble servant. TO DR. EDWARDS. PHILADELPHIA, December 30, 1793.