This is a political book. The Fugitive Slave Law was enacted by Congress in September, 1850, received the signature of HOWELL COBB, [of Georgia, ] as Speaker of the House of Representatives, of WILLIAM R. KING, [of Alabama, ] as President of the Senate, and was 'approved, ' September 18th, of that year, by MILLARD FILLMORE, Acting President of the United States. The authorship of the Bill is generally ascribed to James M. Mason, Senator from Virginia. Before proceeding to the principal object of this tract, it is proper to give a synopsis of the Act itself, which was well called, by the New York Evening Post, 'An Act for the Encouragement of Kidnapping. ' It is in ten sections.