Serious remonstrances, addressed to the citizens of the northern states, and their representatives : being an appeal to their natural feelings & common sense : consisting of speculations and animadversions, on the recent revival of the slave trade, in the American republic : with an investigation relative to the consequent evils resulting to the citizens of the northern states from that event : interspersed with a simplified plan for colonizing the free negroes of the northern, in conjunction with those who have, or may emigrate from the southern states, in a distant part of the national territory : considered as the only possible means of avoiding the deleterious evils attendant on slavery in a republic /