The governor of Liberia has lately made a voyage to England and France, and entered into treaties of amity and commerce with them; and he has obtained naval forces from them, to abolish this traffic in human beings. At the same time, we are affording guaranties to the same traffic. Virginia and Maryland are to the slave trade what the interior of Africa once was. The Potomac and the Chesapeake are the American Niger and Bight of Benin; while this District is the great government barracoon, whence coffles are driven across the country to Alabama or Texas, as slave ships once bore their dreadful cargoes of agony and woe across the Atlantic. The very race, then, which were first stolen, brought to this country, despoiled of all the rights which God had given them, and kept in bondage for generations, at last, after redeeming themselves, or being restored to their natural liberty in some other way, have crossed the ocean, established a government for themselves, and are now setting us an example which should cause our cheeks to blister with shame. Sir, there is an idea often introduced here and elsewhere, and made to bear against any restriction of slavery, or any amelioration of the condition of the slave, which I wish to consider. It was brought odiously and prominently forward the other day, by the gentleman from Pennsylvania, [Mr. CHARLES BROWN.] The idea is, that the slaves are in a better condition in this country than they would have been at home. It is affirmed that they are brought under some degree of civilizing and humanizing influences amongst us, which they would not have felt in the land of their fathers.