On the appearance of this article, containing the above novel declaration of the preponderance of numbers of the colored races in the world, a learned officer of the university was waited upon in the city, on one occasion, and earnestly inquired of concerning the correctness of the statement, desiring, if it were incorrect, to contradict it at once. It was never contradicted. After the return of Mr. Frederick Douglass from England, in the summer of 1846, he visited Pittsburg, where he concluded to form a copartnership in a printing establishment with him. Disposing of his interest in the Mystery, we next find him aiding, by means of his talents and energy, the sustaining of a paper issuing from Rochester, New York, known as the North Star, the early name of the subsequent Frederick Douglass paper. To advance the interest of this, he travelled, holding meetings, and lecturing, so as to obtain subscribers, and endeavored to effect a permanent establishment of a newspaper, as a general organ of the colored people, on a secure basis, by raising an endowment for it, being convinced that this alone would insure its successful continuance. The winter of 1848-9 found him in the eastern part of Pennsylvania, taking part in anti-slavery meetings and conventions, ably seconded by the eloquent Charles L. Remond, to whom, he says, the anti-slavery cause of New England is much indebted for the breaking down of the stupid prejudice, which once existed on the land and water transportations, against colored persons. One of the means resorted to--so zealous were the colored people to sustain the rising North Star--was the holding of fairs in Philadelphia, supported by a number of the most influential colored ladies of that city. At the first of these, December, 1848, it was, that William and Ellen Craft, now in England, the first victims selected under the atrocious Fugitive Slave Law (enacted later), made their appearance, and under circumstances so peculiar as to become historic on both sides of the Atlantic. They were introduced by him to the visitors at the fair in an appropriate address, and in such a way that their mode of escape was carefully concealed, but which was afterwards communicated to the Liberator by an anti-slavery man. Through this their whereabouts became known to Dr. Collins, of Macon, Georgia, and as soon as the enactment was completed, a few years after, he immediately, through his agents sent north, placed all Boston under obligation to arrest them. Hundreds of special or assistant marshals were appointed in the midst of a government which thundered her volleys of welcome to the Hungarian governor, a fugitive from Austrian tyranny! And now, in all our broad free America, there was no place of security from southern slavery for these.