The foregoing advertisements are sufficient for our purpose, scores of similar ones may be gathered from the newspapers of the slave states every month. To the preceding testimony of slaveholders, published by themselves, and vouched for by their own signatures, we subjoin the following testimony of other witnesses to the same point. JOHN M. NELSON, Esq., a native of Virginia, now a highly respected citizen of highland county, Ohio, and member of the Presbyterian Church in Hillsborough, in a recent letter states the following:-- "In Staunton, Va., at the horse of Mr. Robert M'Dowell, a merchant of that place, I once saw a colored woman, of intelligent and dignified appearance, who appeared to be attending to the business of the house, with an _iron collar_ around her neck, with horns or prongs extending out on either side, and up, until they met at something like a foot above her head, at which point there was a bell attached. This _yoke_, as they called it, I understood was to prevent her from running away, or to punish her for having done so. I had frequently seen _men_ with iron collars, but this was the first instance that I recollect to have seen a _female_ thus degraded." Major HORACE NYE, an elder in the Presbyterian Church at Putnam, Muskingum county, Ohio, in a letter, dated Dec. 5, 1838, makes the following statement:-- "Mr. Wm. Armstrong, of this place, who is frequently employed by our citizens as captain and supercargo of descending boats, whose word may be relied on, has just made to me the following statement:-- "While laying at Alexandria, on Red River, Louisiana, he saw a slave brought to a blacksmith's shop and a collar of iron fastened round his neck, with two pieces rivetted to the sides, meeting some distance above his head. At the top of the arch, thus formed, was attached a large cow-bell, the motion of which, while walking the streets, made it necessary for the slave to hold his hand to one of its sides, to steady it. "In New Orleans he saw several with iron collars, with horns attached to them. The first he saw had three prongs projecting from the collar ten or twelve inches, with the letter S on the end of each. He says iron collars are quite frequent there." To the preceding Major Nye adds:-- "When I was about twelve years of age I lived at Marietta, in this state: I knew little of slaves, as there were few or none, at that time, in the part of Virginia opposite that place. But I remember seeing a slave who had run away from some place beyond my knowledge at that time: he had an iron collar round his neck, to which was a strap of iron rivetted to the collar, on each side, passing over the top of the head; and another strap, from the back side to the top of the first--thus inclosing the head on three sides. I looked on while the blacksmith severed the collar with a file, which, I think, took him more than an hour."