BEAUTIES OF THE PECULIAR INSTITUTION--A FEW WELL-SUBSTANTIATED FACTS. A Mr. P----, deceased, of Gallatin, Tenn., for years a slave-trader, had children both by his wife and her body-servant, a beautiful mulatto woman--thus making, generally, the additions to his family in _duplicate_. One of his illegitimate daughters--a beautiful, hazel-eyed mulatto girl--is now the waiting-maid of his widow. This bright mulatto girl is married to a slave belonging to a prominent member of Congress from Tennessee, and has a son, a particularly apt and intelligent boy, whom the rebel women used to send around the camps, head-quarters, and street corners, to obtain the latest news, and report the same to them. Although but eight years old, he was too shrewd to remain quietly a slave. When the daughter of a Federal officer opened a little school, to teach a few contrabands, he came, and learned very rapidly. But his intellectual growth was suddenly stopped by the interference of his _grand_mother, who followed him to the school one day, and dragged him from the room in a perfect rage, threatening to kill him if he ever dared enter a _free_-school again, at the same time declaring to him that "he was not President Lincoln yet." Another instance: The wealthy and prominent Colonel G----, of Gallatin, Tenn., a very _respectable_ and _high-toned_ gentleman, who is reputed a _kind-hearted_ and benevolent man, _remarkably lenient_ toward his slaves, whose praise is in the mouths of our Northern soldiers for his kind hospitalities, finding that his slaves, in view of the coming difficulties, did not increase fast enough for profit, called them all together on the 1st of January, 1862, and said to them: "Now, wenches, mind, every one of you that aint 'big' in three or four months, I intend to sell to the slave-trader." He afterward chuckled over it, adding that it "brought them to terms." Comment needless.