The tributaries flowing into the Ohio River from Virginia and Kentucky furnished convenient channels of escape for many slaves. The concurrent testimony of abolitionists living along the Ohio is to the effect that streams like the Kanawha River bore many a boat-load of fugitives to the southern boundary of the free states. It is not a mere coincidence that a large number of the most important centres of activity lie along the southern line of the Western free states at points near or opposite the mouths of rivers and creeks. On the Mississippi, Ohio and Illinois rivers north-bound steamboats not infrequently provided the means of escape. Jefferson Davis declared in the Senate that many slaves escaped from his state into Ohio by taking passage on the boats of the Mississippi.[224] [224] See p. 312, Chapter X. Abolitionists found it desirable to have waterway extensions of their secret lines. Boats, the captains of which were favorable, were therefore drafted into the service when running on convenient routes. Boats plying between Portland, Maine, and St. John, New Brunswick, or other Canadian ports, often took these passengers free of charge.[225] Thomas Garrett, of Wilmington, Delaware, sometimes sent negroes by steamboat to Philadelphia to be cared for by the Vigilance Committee.[226] It happened on several occasions that fugitives at Portland and Boston were put aboard ocean steamers bound for England.[227] William and Ellen Craft were sent to England after having narrowly escaped capture in Boston.[228] [225] Letters of Brown Thurston, Portland, Me., Jan. 13, 1893, and Oct. 21, 1895. [226] For letters from Mr. Garrett to William Still, of the Acting Committee of Vigilance of Philadelphia, notifying him that fugitives had been sent by boat, see Still's _Underground Railroad Records_, pp. 380, 387. [227] Letter of S. T. Pickard, Portland, Me., Nov. 18, 1893. [228] Still, _Underground Railroad Records_, p. 368; Wilson, _Rise and Fall of the Slave Power_, Vol. II, p. 325; _New England Magazine_, January, 1890, p. 580.