This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Fugitive (Lat. fugire, to flee), literally, one who flees away. Under this head might bo considered two classes of cases: 1, that of fugitives from justice, by which is meant those who flee from one jurisdiction to another to escape prosecution or punishment for crime (see Extradition); 2. that of persons fleeing to avoid compulsory labor for others. It was one of the compromises of the constitution of the United States that "no person held to service or labor in one state, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor, but shall be delivered up on claim of the party to whom such service or labor may be due." (Art. iv., § 2.) Although the word slave was not here employed, the purpose was to provide for the reclamation of slaves fleeing from their masters; and in 1793 an act was passed by congress to give effect to the provision by means of the arrest of any person claimed as a fugitive from slavery, and his return to the state from which he was found to have fled, after a summary judicial hearing.
The repugnance to the institution of slavery on the part of large numbers of people in the northern states rendered this act of little practical value, and another was passed in 1850 with more stringent provisions. Some of these were exceedingly obnoxious, especially that which gave a larger fee to the judicial officer when the person arrested was adjudged to be a slave than when decided to be free, and that which required all persons to assist when called upon in the arrest and return of the person claimed. Although many persons were remanded under this act, the hostility to slavery which was created, or at least intensified by it, probably led to the giving of assistance in a larger number of escapes than had ever been made before, and the act became of little service. A widespread organization to assist fugitives to their liberty became known popularly as the "underground railroad," and a great many persons were aided by it. The act was repealed after the civil war broke out, and the constitutional provision became unimportant after slavery was abolished.