Attempted insurrections, such as that in South Carolina in 1822 and that in Virginia in 1831 in which many whites and blacks were killed, only produced harsher laws and more cruel punishments, until finally the slave became convinced that his only salvation lay in running away.  The North Star was his beacon light of freedom.  A few thousand made their way southward through the chain of swamps that skirt the Atlantic coast and mingled with the Indians in Florida.  Tens of thousands made their way northward along well recognized routes to the free States and to Canada:  the Appalachian ranges with their far-spreading spurs furnished the friendliest of these highways; the Mississippi Valley with its marshlands, forests, and swamps provided less secure hiding places; and the Cumberland Mountains, well supplied with limestone caves, offered a third pathway.  At the northern end of these routes the “Underground Railway"[11] received the fugitives.  From the Cumberlands, leading through the heart of Tennessee and Kentucky, this benevolent transfer stretched through Ohio and Indiana to Canada; from southern Illinois it led northward through Wisconsin; and from the Appalachian route mysterious byways led through New York and New England.

How many thus escaped cannot be reckoned, but it is known that the number of free negroes in the North increased so rapidly that laws discriminating against them were passed in many States.  Nowhere did the negro enjoy all the rights that the white man had.  In some States the free negroes were so restricted in settling as to be virtually prohibited; in others they were disfranchised; in others they were denied the right of jury duty or of testifying in court.  But in spite of this discrimination on the part of the law, a great sympathy for the runaway slave spread among the people, and the fugitive carried into the heart of the North the venom of the institution of which he was the unhappy victim.

Meanwhile the slave trade responded promptly to the lure of gain which the increased demand for cotton held out.  The law of 1807 prohibiting the importation of slaves had, from the date of its enactment, been virtually a dead letter.  Messages of Presidents, complaints of government attorneys, of collectors and agents called attention to the continuous violation of the law; and its nullity was a matter of common knowledge.  When the market price of a slave rose to $325 in 1840 and to $500 after 1850, the increase in profits made slave piracy a rather respectable business carried on by American citizens in American built ships flying the American flag and paying high returns on New York and New England capital.  Owing to this steady importation there was a constant intermingling of raw stock from the jungles with the negroes who had been slaves in America for several generations.